The British Columbia Building Code | Note to Part 9 | Housing and Small Buildings Pt 1

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Notes to Part 9

Housing and Small Buildings

A-9.1.1.1.(1) Application of Part 9 to Seasonally and Intermittently Occupied Buildings. The British Columbia

Building Code does not provide separate requirements which would apply to seasonally or intermittently occupied buildings. Without

compromising the basic health and safety provisions, however, various requirements in Part 9 recognize that leniency may be

appropriate in some circumstances. With greater use of “cottages” through the winter months, the proliferation of seasonally occupied

multiple-dwelling buildings and the increasing installation of modern conveniences in these buildings, the number and extent of

possible exceptions is reduced.

Energy Efficiency

Clause 9.36.1.3.(5)(b) exempts seasonally occupied residential buildings such as summer cottages from the requirements of

Section 9.36. Cottages intended for continuous or regular winter use such as ski cabins are required to conform to Section 9.36.

Thermal Insulation

Article 9.25.2.1. specifies that insulation is to be installed in walls, ceilings and floors which separate heated space from unheated

space. Cottages intended for use only in the summer and which, therefore, have no space heating appliances, would not be

required to be insulated. Should a heating system be installed at some later date, insulation should also be installed at that time in

accordance with Article 9.25.1.1. and the insulation tables in Section 9.36. However, if the building were not intended for

continuous or regular winter use, it may still be exempted from the remainder of the energy efficiency requirements in

Section 9.36.

Air Barrier Systems and Vapour Barriers

Articles 9.25.3.1. and 9.25.4.1. require the installation of air barrier systems and vapour barriers only where insulation is installed.

Dwellings with no heating system would thus be exempt from these requirements. In some cases, seasonally occupied buildings

that are conditioned may be required to conform to the air and vapour barrier requirements of Section 9.25, but not to the air

barrier and other requirements of Section 9.36.

Interior Wall and Ceiling Finishes

The choice of interior wall and ceiling finishes has implications for fire safety. Where a dwelling is a detached building, there are

no fire resistance requirements for the walls or ceilings within the dwelling. The exposed surfaces of walls and ceilings are required

to have a flame-spread rating not greater than 150 (Subsection 9.10.17.). There is, therefore, considerable flexibility, even in

continuously occupied dwellings, with respect to the materials used to finish these walls. Except where waterproof finishes are

required (Subsection 9.29.2.), ceilings and walls may be left unfinished. Where two units adjoin, however, additional fire

resistance requirements may apply to interior loadbearing walls, floors and the shared wall (Article 9.10.8.3., and

Subsections 9.10.9. and 9.10.11.).

Plumbing and Electrical Facilities

Plumbing fixtures are required only where a piped water supply is available (Subsection 9.31.4.), and electrical facilities only

where electrical services are available (Article 9.34.1.2.).

A-9.3.1.7. Ratio of Water to Cementing Material. While adding water to concrete on site may facilitate its distribution

through formwork, this practice can have several undesirable results, such as reduced strength, greater porosity, and more propensity to

shrinkage cracking. The ratio of water to cementing material is determined according to weight. For example, using Table 9.3.1.7.,

the maximum water-cement ratio of 0.45 for a 20 mm coarse aggregate would require 18 kg (or 18 L) of water (1 L of water

weighs 1 kg).

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.3.2.1.(1) Grade Marking of Lumber. Lumber is generally grouped for marketing into the species combinations

contained in Table A-9.3.2.1.(1)-A. The maximum allowable spans for those combinations are listed in the span tables for joists,

rafters and beams. Some species of lumber are also marketed individually. Since the allowable span for the northern species

combination is based on the weakest species in the combination, the use of the span for this combination is permitted for any

individual species not included in the Spruce-Pine-Fir, Douglas Fir-Larch and Hemlock-Fir combinations.

Facsimiles of typical grade marks of lumber associations and grading agencies accredited by the Canadian Lumber Standards (CLS)

Accreditation Board to grade mark lumber in Canada are shown in Table A-9.3.2.1.(1)-B. Accreditation by the CLS Accreditation

Board applies to the inspection, grading and grade marking of lumber, including mill supervisory service, in accordance with

CSA O141, “Softwood Lumber.”

The grade mark of a CLS accredited agency on a piece of lumber indicates its assigned grade, species or species combination, moisture

condition at the time of surfacing, the responsible grader or mill of origin and the CLS accredited agency under whose supervision the

grading and marking was done.

Canadian lumber is graded to the “Standard Grading Rules for Canadian Lumber,” published by the National Lumber Grades

Authority. These rules specify standard grade names and grade name abbreviations for use in grade marks to provide positive

identification of lumber grades. In a similar fashion, standard species names or standard species abbreviations, symbols or marks are

provided in the rules for use in grade marks.

Grade marks denote the moisture content of lumber at the time of surfacing. “S-Dry” in the mark indicates the lumber was surfaced at

a moisture content not exceeding 19%. “MC 15” indicates a moisture content not exceeding 15%. “S-GRN” in the grade mark

signifies that the lumber was surfaced at a moisture content higher than 19% at a size to allow for natural shrinkage during seasoning.

Each mill or grader is assigned a permanent number. The point of origin of lumber is identified in the grade mark by use of a mill or

grader number or by the mill name or abbreviation. The CLS certified agency under whose supervision the lumber was grade marked

is identified in the mark by the registered symbol of the agency.

Table A-9.3.2.1.(1)-A

Species Designations and Abbreviations

Forming Part of Note A-9.3.2.1.(1)

Commercial Designation of Species or Species

Combination

Abbreviation Permitted on Grade

Stamps

Species Included

Douglas Fir – Larch D Fir – L (N) Douglas Fir, Western Larch

Hemlock – Fir Hem – Fir (N) Western Hemlock, Amabilis Fir

Spruce – Pine – Fir

S – P – F or

Spruce – Pine – Fir

White Spruce, Engelmann Spruce, Black Spruce, Red

Spruce, Lodgepole Pine, Jack Pine, Alpine Fir, Balsam Fir

Northern Species North Species

Any Canadian softwood covered by the

“Standard Grading Rules for Canadian Lumber”

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Table A-9.3.2.1.(1)-B

Facsimiles of Grade Marks Used by Canadian Lumber Manufacturing Associations and Agencies

Authorized to Grade Mark Lumber in Canada

Forming Part of Note A-9.3.2.1.(1)

Facsimiles of Grade Mark Association or Agency

Alberta Forest Products Association

www.albertaforestproducts.ca

Canadian Mill Services Association

www.canserve.org

Canadian Softwood Inspection Agency Inc.

www.canadiansoftwood.com

Central Forest Products Association Inc.

c/o Alberta Forest Products Association

www.albertaforestproducts.ca

GG00056B

A.F .P .A.

–

NLG

GG00062B

CMSA

KD-HT

NLGA

GG00098A

D-HTD - H T

D FIRFIR-

(

)

GAGA

CSI

GG00058B

NLGA

-HTHT

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Council of Forest Industries

www.cofi.org

Macdonald Inspection Services Ltd.

www.gradestamp.com

Maritime Lumber Bureau

www.mlb.ca

Newfoundland & Labrador Lumber Producers’ Association

www3.nf.sympatico.ca/nllpa

Table A-9.3.2.1.(1)-B (continued)

Facsimiles of Grade Marks Used by Canadian Lumber Manufacturing Associations and Agencies

Authorized to Grade Mark Lumber in Canada

Forming Part of Note A-9.3.2.1.(1)

Facsimiles of Grade Mark Association or Agency

GG00057B

S-P-F

NLGA

NLGANLGA

KD-HT

D FIRD FIR - - L(N)L(N)

GG00064B

No. 2

S - P - F

NLGA

S-P-F

No.1

KD-HT

NLGA

GG00065B

GG00066B

NLGAN L G A

NO.NO.

000

KD HTKD HT

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-Table 9.3.2.1. Lumber Grading. To identify board grades, the paragraph number of the NLGA “Standard Grading Rules

for Canadian Lumber” under which the lumber is graded must be shown in the grade mark. Paragraph 113 is equivalent to the

WWPA “Western Lumber Grading Rules” and paragraph 114 is equivalent to the WCLIB “Standard Grading Rules.” When graded

in accordance with WWPA or WCLIB rules, the grade mark will not contain a paragraph number.

Northwest Territories Forest Industries Association

Ontario Forest Industries Association

www.ofia.com

Ontario Lumber Manufacturers’ Association

(Home of CLA Grading and Inspection)

www.olma.ca

Pacific Lumber Inspection Bureau

www.plib.org

Quebec Forest Industry Council

(Conseil de l’industrie forestière du Québec)

www.qfic.gc.ca

Table A-9.3.2.1.(1)-B (continued)

Facsimiles of Grade Marks Used by Canadian Lumber Manufacturing Associations and Agencies

Authorized to Grade Mark Lumber in Canada

Forming Part of Note A-9.3.2.1.(1)

Facsimiles of Grade Mark Association or Agency

GG00067B

10 10

NLGA

GRN

CONST S

GG00059B

CLA

100

S-P-F

NLGA

KD-HT

GG00068B

O.L.M.A. 09

1 1

NLGA

GG00069B

NO. 1

0 0

NLGA RULES

GG00070B

477477

S-P-FS-P-F

KD-HTKD-HT

NLGANLGA

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.3.2.8.(1) Non-Standard Lumber. NLGA 2014, “Standard Grading Rules for Canadian Lumber,” permits lumber to

be dressed to sizes below the standard sizes (38 × 89, 38 × 140, 38 × 184, etc.) provided the grade stamp shows the reduced size.

This Sentence permits the use of the span tables for such lumber, provided the size indicated on the stamp is not less than 95% of

the corresponding standard size. Allowable spans in the tables must be reduced a full 5% even if the undersize is less than the

5% permitted.

A-9.3.2.9.(1) Protection from Termites.

Figure A-9.3.2.9.(1)-A

Known termite locations

Note to Figure A-9.3.2.9.(1)-A:

(1) Reference: J.K. Mauldin (1982), N.Y. Su (1995), T. Myles (1997).

Manitoba

Northwest

Territories

Nunavut

Yuko n

P.E.I.

EG02049A

British

Columbia

Quebec

Hudson

Bay

New

Brunswick

Nova

Scotia

Newfoundland

Areas in which specific

locations with termites

have been identified.

Alberta

Saskatchewan

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.3.2.9.(1)-B

Clearances under structural wood elements and visibility of supporting elements where required to permit inspection for

termite infestation

Note to Figure A-9.3.2.9.(1)-B:

(1) For the height of structural wood elements not directly above finished ground, see Article 9.23.2.3.

A-9.3.2.9.(3) Protection of Structural Wood Elements from Moisture and Decay. There are many above-ground,

structural wood systems where precipitation is readily trapped or drying is slow, creating conditions conducive to decay. Beams

extending beyond roof decks, junctions between deck members, and connections between balcony guards and walls are three examples

of elements that can accumulate water when exposed to precipitation if they are not detailed to allow drainage.

A-9.3.2.9.(4) Protection of Retaining Walls and Cribbing from Decay. Retaining walls supporting soil are considered

to be structural elements of the building if a line drawn from the outer edge of the footing to the bottom of the exposed face of the

retaining wall is greater than 45° to the horizontal. Retaining walls supporting soil may be structural elements of the building if the line

described above has a lower slope.

Figure A-9.3.2.9.(4)

Identifying retaining walls that require preservative treatment

Retaining walls that are not critical to the support of building foundations but are greater than 1.2 m in height may pose a danger of

sudden collapse to persons adjacent to the wall if the wood is not adequately protected from decay. The height of the retaining wall or

cribbing is measured as the vertical difference between the ground levels on each side of the wall.

A-9.4.1.1. Structural Design. Article 9.4.1.1. establishes the principle that the structural members of Part 9 buildings must

• comply with the prescriptive requirements provided in Part 9,

• be designed in accordance with accepted good practice, or

• be designed in accordance with Part 4 using the loads and limits on deflection and vibration specified in Part 9 or Part 4.

Usually a combination of approaches is used. For example, even if the snow load calculation on a wood roof truss is based on

Subsection 9.4.2., the joints must be designed in accordance with Part 4. Wall framing may comply with the prescriptive requirements

in Subsections 9.23.3., 9.23.10., 9.23.11. and 9.23.12., while the floor framing may be engineered.

EG02050B

supporting elements visible

to permit inspection

(1)

clear height of 450 mm between

structural wood elements and

finished ground directly below

≥ 450 mm

wall

height

< 45˚: retaining wall may be

supporting the building

> 45˚: retaining wall is

supporting the building

EG02051A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Design according to Part 4 or accepted good engineering practice, such as that described in CWC 2014, “Engineering Guide for

Wood Frame Construction,” requires engineering expertise. The CWC Guide contains alternative solutions and provides information

on the applicability of the Part 9 prescriptive structural requirements to further assist designers and building officials to identify the

appropriate design approach. The need for professional involvement in the structural design of a building, whether to Part 4 or Part 9

requirements or accepted good practice, is defined by provincial and territorial legislation.

A-9.4.2.1.(1) Soft Conversion from Imperial Units. The conversion table at the end of the Code provides factors for the

conversion of millimeters to inches. However, not all metric measurements stated in the Code are exact conversions. For example,

while the dimensions given for wood framing members are the exact dimensions of the milled product – i.e., what is commonly

referred to as a “2 × 4” is actually 1.5 in. × 3.5 in., which, in mm, is 38 × 89 – the metric dimensions given for spacing between

framing elements are actually soft conversions:

It remains common construction practice to arrange joists, rafters and studs in 12, 16 or 24 in. increments so as to properly align them

with the edges of sheathing materials. It is therefore assumed that structural elements will be spaced according to the actual

metric equivalents.

A-9.4.2.2. Application of Simplified Part 9 Snow Loads. The simplified specified snow loads described in

Article 9.4.2.2. may be used where the structure is of the configuration that is typical of traditional wood-frame residential

construction and its performance. This places limits on the spacing of joists, rafters and trusses, the spans of these members and

supporting members, deflection under load, overall dimensions of the roof and the configuration of the roof. It assumes considerable

redundancy in the structure.

Because very large buildings may be constructed under Part 9 by constructing firewalls to break up the building area, it is possible to

have Part 9 buildings with very large roofs. The simplified specified snow loads may not be used when the total roof area of the overall

structure exceeds 4550 m

. Thus, the simplified specified snow load calculation may be used for typical townhouse construction but

would not be appropriate for much larger commercial or industrial buildings, for example.

The simplified specified snow loads are also not designed to take into account roof configurations that seriously exacerbate snow

accumulation. This does not pertain to typical projections above a sloped roof, such as dormers, nor does it pertain to buildings with

higher and lower roofs. Although two-level roofs generally lead to drift loading, smaller light-frame buildings constructed according to

Part 9 have not failed under these loads. Consequently, the simplified calculation may be used in these cases. Rather, this limitation on

application of the simplified calculation pertains to roofs with high parapets or significant other projections above the roof, such as

elevator penthouses, mechanical rooms or larger equipment that would effectively collect snow and preclude its blowing off the roof.

The reference to Article 9.4.3.1. invokes, for roof assemblies other than common lumber trusses, the same performance criteria

for deflection.

The specific weight of snow on roofs, , obtained from measurements at a number of weather stations across Canada varied from about

1.0 to 4.5 kN/m

. An average value for use in design in lieu of better local data is  =3.0 kN/m

. In some locations the specific weight

of snow may be considerably greater than 3.0 kN/m

. Such locations include regions where the maximum snow load on the roof is

reached only after contributions from many snowstorms, coastal regions, and regions where winter rains are considerable and where a

unit weight as high as 4.0 kN/m

may be appropriate.

A-9.4.2.3.(1) Accessible Platforms Subject to Snow and Occupancy Loads. Many platforms are subject to both

occupancy loads and snow loads. These include balconies, decks, verandas, flat roofs over garages and carports. Where such a platform,

or a segregated area of such a platform, serves a single dwelling unit, it must be designed for the greater of either the specified snow

load or an occupancy load of 1.9 kPa. Where the platform serves more than one single dwelling unit or an occupancy other than a

residential occupancy, higher occupancy loads will apply as specified in Table 4.1.5.3.

Table A-9.4.2.1.(1)

Imperial Unit Exact Metric Conversion Soft Metric Conversion Used in Code

12 in. 305 mm 300 mm

16 in. 406 mm 400 mm

24 in. 610 mm 600 mm

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.4.2.4.(1) Specified Loads for Attics or Roof Spaces with Limited Accessibility. Typical residential roofs are

framed with roof trusses and the ceiling is insulated.

Residential trusses are placed at 600 mm on centre with web members joining top and bottom chords. Lateral web bracing is installed

perpendicular to the span of the trusses. As a result, there is limited room for movement inside the attic or roof space or for storage of

material. Access hatches are generally built to the minimum acceptable dimensions, further limiting the size of material that can be

moved into the attic or roof space.

With exposed insulation in the attic or roof space, access is not recommended unless protective clothing and breathing apparatus

are worn.

Thus the attic or roof space is recognized as uninhabitable and loading can be based on actual dead load. In emergency situations or for

the purpose of inspection, it is possible for a person to access the attic or roof space without over-stressing the truss or causing

damaging deflections.

A-Table 9.4.4.1. Classification of Soils. Sand or gravel may be classified by means of a picket test in which a 38 mm by

38 mm picket beveled at the end at 45° to a point is pushed into the soil. Such material is classified as “dense or compact” if a man of

average weight cannot push the picket more than 200 mm into the soil and “loose” if the picket penetrates 200 mm or more.

Clay and silt may be classified as “stiff” if it is difficult to indent by thumb pressure, “firm” if it can be indented by moderate thumb

pressure, “soft” if it can be easily penetrated by thumb pressure, where this test is carried out on undisturbed soil in the wall of a

test pit.

A-9.4.4.4.(1) Soil Movement. In susceptible soils, changes in temperature or moisture content can cause significant expansion

and contraction. Soils containing pyrites can expand simply on exposure to air.

Expansion and Contraction due to Moisture

Clay soils are most prone to expansion and contraction due to moisture. Particularly wet seasons can sufficiently increase the

volume of the soil under and around the structure to cause heaving of foundations and floors-on-ground, or cracking of

foundation walls. Particularly dry seasons or draw-down of water by fast-growing trees can decrease the volume of the soil

supporting foundations and floors-on-ground, thus causing settling.

Frost Heave

Frost heave is probably the most commonly recognized phenomenon related to freezing soil. Frost heave results when moisture

in frost-susceptible soil (clay and silt) under the footings freezes and expands. This mechanism is addressed by requirements in

Section 9.12. regarding the depth of excavations.

Ice Lenses

When moisture in frost-susceptible soils freezes, it forms an ice lens and reduces the vapour pressure in the soil in the area

immediately around the lens. Moisture in the ground redistributes to rebalance the vapour pressures providing more moisture in

the area of the ice lens. This moisture freezes to the lens and the cycle repeats itself. As the ice lens grows, it exerts pressure in the

direction of heat flow. When lenses form close to foundations and heat flow is toward the foundation – as may be the case with

unheated crawl spaces or open concrete block foundations insulated on the interior – the forces may be sufficient to crack

the foundation.

Adfreezing

Ice lenses can adhere themselves to cold foundations. Where heat flow is essentially upward, parallel to the foundation, the

pressures exerted will tend to lift the foundation. This may cause differential movement or cracking of the foundation. Heat loss

through basement foundations of cast-in-place concrete or concrete block insulated on the exterior appears to be sufficient to

prevent adfreezing. Care must be taken where the foundation does not enclose heated space or where open block foundations are

insulated on the interior. The installation of semi-rigid glass fibre insulation has demonstrated some effectiveness as a separ

ation

layer to absorb

the adfreezing forces.

Pyrites

Pyrite is the most common iron disulphide mineral in rock and has been identified in rock of all types and ages. It is most

commonly found in metamorphic and sedimentary rock, and especially in coal and shale deposits.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Weathering of pyritic shale is a chemical-microbiological oxidation process that results in volume increases that can heave

foundations and floors-on-ground. Concentrations of as little as 0.1% by weight have caused heaving. Weathering can be

initiated simply by exposing the pyritic material to air. Thus, building on soils that contain pyrites in concentrations that will

cause damage to the building should be avoided, or measures should be taken to remove the material or seal it. Material

containing pyrites should not be used for backfill at foundations or for supporting foundations or floors-on-ground.

Where it is not known if the soil or backfill contains pyritic material in a deleterious concentration, a test is available to identify its

presence and concentration.

References:

(1) Legget, R.F. and Crawford, C.B. Trees and Buildings. Canadian Building Digest 62, Division of Building Research, National

Research Council Canada, Ottawa, 1965.

(2) Hamilton, J.J. Swelling and Shrinking Subsoils. Canadian Building Digest 84, Division of Building Research, National

Research Council Canada, Ottawa, 1966.

(3) Hamilton, J.J. Foundations on Swelling and Shrinking Subsoils. Canadian Building Digest 184, Division of Building

Research, National Research Council Canada, Ottawa, 1977.

(4) Penner, W., Eden, W.J., and Gratten-Bellew, P.E. Expansion of Pyritic Shales. Canadian Building Digest 52, Division of

Building Research, National Research Council Canada, Ottawa, 1975.

(5) Swinton, M.C., Brown, W.C., and Chown, G.A. Controlling the Transfer of Heat, Air and Moisture through the Building

Envelope. Small Buildings – Technology in Transition, Building Science Insight ’90, Institute for Research in Construction,

National Research Council Canada, Ottawa, 1990.

A-9.4.4.6. and 9.15.1.1. Loads on Foundations. The prescriptive solutions provided in Part 9 relating to footings and

foundation walls only account for the loads imposed by drained earth. Drained earth is assumed to exert a load equivalent to the load

that would be exerted by a fluid with a density of 480 kg/m

. The prescriptive solutions do not account for surcharges from saturated

soil or additional loads from heavy objects located adjacent to the building. Where such surcharges are expected, the footings and

foundation walls must be designed and constructed according to Part 4.

A-9.5.1.2. Combination Rooms. If a room draws natural light and natural ventilation from another area, the opening

between the two areas must be large enough to effectively provide sufficient light and air. This is why a minimum opening of 3 m

required, or the equivalent of a set of double doors. The effectiveness of the transfer of light and air also depends on the size of the

transfer opening in relation to the size of the dependent room; in measuring the area of the wall separating the two areas, the whole

wall on the side of the dependent room should be considered, not taking into account offsets that may be in the surface of the wall.

The opening does not necessarily have to be in the form of a doorway; it may be an opening at eye level. However, if the dependent

area is a bedroom, provision must be made for the escape window required by Article 9.9.10.1. to fulfill its safety function. This is why

a direct passage is required between the bedroom and the other area; the equivalent of at least a doorway is therefore required for direct

passage between the two areas.

A-9.5.5.3. Doorways to Rooms with a Bathtub, Shower or Water Closet. If the minimum 860 mm hallway serves

more than one room with identical facilities, only one of the rooms is required to have a door not less than 760 mm wide.

If a number of rooms have different facilities, for example, one room has a shower, lavatory and water closet, and another room has a

lavatory and water closet, the room with the shower, lavatory and water closet must have the minimum 760 mm wide door.

Where multiple rooms provide the same or similar facilities, one of these rooms must comply with the requirement to have at least one

bathtub or shower, one lavatory and one water closet. Where the fixtures are located in two separate rooms served by the same hallway,

the requirement for the minimum doorway width would apply to both rooms.

If the minimum 860 mm hallway does not serve any room containing a bathtub, shower and water closet, additional fixtures do not

need to be installed.

A-9.6.1.1.(1) Application. The scope of this Section includes glass installed on the interior or on the exterior of a building.

A-9.6.1.2.(2) Mirrored Glass Doors. CAN/CGSB-82.6-M, “Doors, Mirrored Glass, Sliding or Folding, Wardrobe,” covers

mirrored glass doors for use on reach-in closets. It specifies that such doors are not to be used for walk-in closets.

A-Table 9.6.1.3. Glass in Doors. Maximum areas in Table 9.6.1.3.-G for other than fully tempered glazing are cut off at

1.50 m

, as this would be the practical limit after which safety glass would be required by Sentence 9.6.1.4.(2).

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.7. Windows, Doors and Skylights. This section applies only to windows, doors and skylights as defined in the scope of

the standards referenced in Article 9.7.4.2. Other glazed products, such as site-built windows, curtain walls or sloped glazing, are

required to conform to Part 5.

It is also permitted for fenestration products within the scope of the NAFS standard to conform to Part 5. This option is typically used

for windows and doors that are impractical to subject to the testing requirements of NAFS due to their size or for custom

configurations.

A-9.7.3.2.(1)(a) Minimizing Condensation. The total prevention of condensation on the surfaces of fenestration products is

difficult to achieve and, depending on the design and construction of the window or door, may not be absolutely necessary.

Clause 9.7.3.2.(1)(a) therefore requires that condensation be minimized, which means that the amount of moisture that condenses on

the inside surface of a window, door or skylight, and the frequency at which this occurs, must be limited. The occurrence of such

condensation must be sufficiently rare, the accumulation of any water must be sufficiently small, and drying must be sufficiently rapid

to prevent the deterioration of moisture-susceptible materials and the growth of fungi.

A-9.7.4. Design and Construction. Garage doors, sloped glazing, curtain walls, storefronts, commercial entrance systems,

site-built or site-glazed products, revolving doors, interior windows and doors, storm windows, storm doors, sunrooms and

commercial steel doors are not in the scope of NAFS.

All windows, doors and skylights installed to separate conditioned space from unconditioned space or the exterior must also conform

to Section 9.36.

A-9.7.4.2.(1) Standards Referenced for Windows, Doors and Skylights.

General

Doors between an unconditioned garage and a dwelling unit are considered to be in scope of the standard referenced in this

Sentence. Although the standard refers to windows in “exterior building envelopes”, a note to the definition of “building

envelope” clarifies that for the purpose of application of the standard, in some cases a building envelope may consist of 2 separate

walls (such as a wall between garage and dwelling unit as well as the exterior wall of the garage itself).

A door leading to the exterior from an unconditioned garage is also within scope of the referenced standard, as it is also part of the

exterior building envelope. However, because the scope of the BC Building Code takes precedence, these doors are not required to

conform to “NAFS”. This Subsection of the Code does not apply to a door separating two unconditioned spaces.

Canadian Requirements in the Harmonized Standard

In addition to referencing the Canadian Supplement, CSA A440S1, “Canadian Supplement to AAMA/WDMA/CSA

101/I.S.2/A440, NAFS – North American Fenestration Standard/Specification for Windows, Doors, and Skylights,” the

Harmonized Standard, AAMA/WDMA/CSA 101/I.S.2/A440, “NAFS – North American Fenestration Standard/Specification

for Windows, Doors, and Skylights,” contains some Canada-specific test criteria.

Standards Referenced for Excluded Products

Clause 1.1, General, of the Harmonized Standard defines the limits to the application of the standard with respect to various

types of fenestration products. A list of exceptions to the application statement identifies a number of standards that apply to

excluded products. Compliance with those standards is not required by the Code; the references are provided for information

purposes only.

Label Indicating Performance and Compliance with Standard

The Canadian Supplement requires that a product’s performance ratings be indicated on a label according to the designation

requirements in the Harmonized Standard and that the label include

• design pressure, where applicable,

•

negative design pressure, where applicable,

• water penetration test pressure, and

• the Canadian air infiltration and exfiltration levels.

It should be noted that, for a product to carry a label in Canada, it must meet all of the applicable requirements of both the

Harmonized Standard and the Canadian Supplement, including the forced entry requirements.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Water Penetration Resistance

For the various performance grades listed in the Harmonized Standard, the corresponding water penetration resistance test

pressures are a percentage of the design pressure. For R-class products, water penetration resistance test pressures are 15% of

design pressure. In Canada, driving rain wind pressures (DRWP) have been determined for the locations listed in Appendix C.

These are listed in the Canadian Supplement. The DRWP given in the Canadian Supplement must be used for all products

covered in the scope of the Harmonized Standard when used in buildings within the scope of Part 9.

To achieve equivalent levels of water penetration resistance for all locations, the Canadian Supplement includes a provision for

calculating specified DRWP at the building site considering building exposure. Specified DRWP values are, in some cases, greater

than 15% of design pressure and, in other cases, less than 15% of design pressure. For a fenestration product to comply with the

Code, it must be able to resist the structural and water penetration loads at the building site. Reliance on a percentage of design

pressure for water penetration resistance in the selection of an acceptable fenestration product will not always be adequate.

Design pressure values are reported on a secondary designator, which is required by the Canadian Supplement to be affixed to the

window.

As an alternative to the above noted provision in the Canadian Supplement for calculating specified DRWP, the Water Resistance

values listed in Table C-4 of Appendix C may be used.

Uniform Load Structural Test

The Harmonized Standard specifies that fenestration products be tested at 150% of design pressure for wind (specified wind load)

and that skylights and roof windows be tested at 200% of design pressure for snow (specified snow load). With the change in the

British Columbia Building Code 2006 to a 1-in-50 return period for wind load, a factor of 1.4 rather than 1.5 is now applied for

wind. The British Columbia Building Code has traditionally applied a factor of 1.5 rather than 2.0 for snow. Incorporating these

lower load factors into the Code requirements for fenestration would better reflect acceptable minimum performance levels;

however, this has not been done in order to avoid adding complexity to the Code, to recognize the benefits of Canada-US

harmonization, and to recognize that differentiation of products that meet the Canadian versus the US requirements would add

complexity for manufacturers, designers, specifiers and regulatory officials.

The required design pressure and Performance Grade (PG) rating of doors and windows has been listed for each of the geographic

locations found in the Code in Table C-4. These may be used as an alternative to the specified wind load calculations in the

Canadian Supplement.

Condensation Resistance

The Harmonized Standard identifies three test procedures that can be used to determine the condensation resistance of windows

and doors. Only the physical test procedure given in CSA A440.2, “Fenestration Energy Performance” can be used to establish

Temperature Index (I) values. Computer simulation tools can also be used to estimate the relative condensation resistance of

windows, but these methods employ different expressions of performance known as Condensation Resistance Factors (CR). I and

CR values are not interchangeable.

Where removable multiple glazing panels (RMGP) are installed on the inside of a window, care should be taken to hermetically

seal the RMGP against the leakage of moisture-laden air from the interior into the cavity on the exterior of the RMGP because the

moisture transported by the air could lead to significant condensation on the interior surface of the outside glazing.

Basement Windows

Clause 12.4.2, Basement Windows, of the Harmonized Standard refers to products that are intended to meet Code requirements

for ventilation and emergency egress. The minimum test size of 800 mm × 360 mm (total area of 0.288 m

) specified in the

standard will not provide the minimum openable area required by the Code for bedrooms (i.e. 0.35 m

with no dimension less

than 380 mm) and the means to provide minimum open area identified in the standard is inconsistent with the requirements of

the Code (see Subsection 9.9.10. for bedroom windows). The minimum test size specified in the standard will also not provide

the minimum ventilation area of 0.28 m

required for non-heating-season natural ventilation (see Article 9.32.2.2.).

Performance of Doors: Limited Water Ingress Control

While the control of precipitation ingress is a performance requirement for exterior doors, side-hinged doors can comply with the

referenced standard, AAMA/WDMA/CSA 101/I.S.2/A440, “NAFS – North American Fenestration Standard/Specification for

Windows, Doors, and Skylights,” when tested at a pressure differential of 0 Pa (0.0 psf) or higher, but less than the minimum test

pressure required for the indicated performance class and performance grade. Such doors are identified with a “Limited Water”

(LW) rating on the product label.

Conditions suitable for the installation of an LW rated door are identified in Sentence 9.7.4.2.(2).

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.7.4.3.(2) Performance Requirements. If the option of calculating design pressure performance grade and water

resistance values using the Canadian Supplement is chosen, the DRWP values in Table A.1 of that standard must be used for all

buildings within the scope of Part 9 of the BC Building Code. This requirement applies whether the windows, doors and skylights are

designed to conform to Article 9.7.4.2. or to Part 5.

A-9.7.5.2.(1) Forced Entry Via Glazing in Doors and Sidelights. There is no mandatory requirement that special glass

be used in doors or sidelights, primarily because of cost. It is, however, a common method of forced entry to break glass in doors and

sidelights to gain access to door hardware and unlock the door from the inside. Although insulated glass provides increased resistance

over single glazing, the highest resistance is provided by laminated glass. Tempered glass, while stronger against static loads, is prone to

shattering under high, concentrated impact loads.

Figure A-9.7.5.2.(1)

Combined laminated/annealed glazing

Laminated glass is more expensive than annealed glass and must be used in greater thicknesses. Figure A-9.7.5.2.(1) shows an insulated

sidelight made of one pane of laminated glass and one pane of annealed glass. This method reduces the cost premium that would result

if both panes were laminated.

Consideration should be given to using laminated glazing in doors and accompanying sidelights regulated by Article 9.6.1.3., in

windows located within 900 mm of locks in such doors, and in basement windows.

Underwriters’ Laboratories of Canada have produced ULC-S332, “Burglary Resisting Glazing Material,” which provides a test

procedure to evaluate the resistance of glazing to attacks by thieves. While it is principally intended for plate glass show windows,

it may be of value for residential purposes.

A-9.7.5.2.(6) Door Fasteners. The purpose of the requirement for 30 mm screw penetration into solid wood is to prevent the

door from being dislodged from the jamb due to impact forces. It is not the intent to prohibit other types of hinges or strikeplates that

are specially designed to provide equal or greater protection.

A-9.7.5.2.(8) Hinged Doors. Methods of satisfying this Sentence include either using non-removable pin hinges or modifying

standard hinges by screw fastening a metal pin in a screw hole in one half of the top and bottom hinges. When the door is closed,

the projecting portion of the pin engages in the corresponding screw hole in the other half of the hinge and then, even if the hinge pin

is taken out, the door cannot be removed.

A-9.7.5.3.(1) Resistance of Windows to Forced Entry. Although this Sentence only applies to windows within 2 m of

adjacent ground level, certain house and site features, such as balconies or canopy roofs, allow for easy access to windows at higher

elevations. Consideration should be given to specifying break-in resistant windows in such locations.

This Sentence does not apply to windows that do not serve the interior of the dwelling unit, such as windows to garages, sun rooms or

greenhouses, provided connections between these spaces and the dwelling unit are secure.

One method that is often used to improve the resistance of windows to forced entry is the installation of metal “security bars.”

However, while many such installations are effective in increasing resistance to forced entry, they may also reduce or eliminate the

usefulness of the window as an exit in case of fire or other emergency that prevents use of the normal building exits. Indeed, unless

such devices are easily openable from the inside, their installation in some cases would contravene the requirements of

Article 9.9.10.1., which requires every bedroom that does not have an exterior door to have at least one window that is large enough

and easy enough to open that it can be used as an exit in case of emergency. Thus an acceptable security bar system should be easy to

open from the inside while still providing increased resistance to entry from the outside.

1 x 6 mm laminated glass

1 x 6 mm annealed glass

spacer

EG00315B

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.8.4. Tread Configurations. The Code distinguishes four principal types of stair treads:

• rectangular treads, which are found in straight flights;

• tapered treads, which are found in curved flights, (the term tapered tread also includes winders)

; and

winders are described in Note A-9.8.4.6.See Figure A-9.8.4.-A.

Figure A-9.8.4.-A

Types of treads

Articles 9.8.4.1. to 9.8.4.8. specify various dimensional limits for steps. Figure A-9.8.4.-B illustrates the elements of a step and how

these are to be measured.

Figure A-9.8.4.-B

Elements of steps and their measurement

Rectangular treads

Tapered treads

Winders

EG02055D

30º

45º

EG00689A

tread depth:

measured nosing to riser

run:

measured

nosing to nosing

rise:

measured

nosing to nosing

top of nosing

with rounded or

bevelled edge

6 mm to 14 mm

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.8.4.6. Winders. Where a stair must turn, the safest method of incorporating the turn is to use a landing. Within a dwelling

unit, however, where occupants are familiar with their environment, winders are an acceptable method of reducing the amount of

floor area devoted to the stair and have not been shown to be more hazardous than a straight run of steps. Nevertheless, care is required

to ensure that winders are as safe as possible. Experience has shown that 30° winders are the best compromise and require the least

change in the natural gait of the stair user; 45° winders are also acceptable, as they are wider. The Code permits only these two angles.

Although it is normal Code practice to specify upper and lower limits, in this case it is necessary to limit the winders to specific angles

with no tolerance above or below these angles other than normal construction tolerances. One result of this requirement is that

winder-type turns in stairs are limited to 30° or 45° (1 winder), 60° (2 winders), or 90° (2 or 3 winders). See Figure A-9.8.4.6.

Figure A-9.8.4.6.

Winders

A-9.8.4.8. Tread Nosings. A sloped or beveled edge on tread nosings will make the tread more visible through light modeling.

The sloped portion of the nosing must not be too wide so as to reduce the risk of slipping of the foot. See Figure A-9.8.4.-B.

A-9.8.7.1.(2) Wider Stairs than Required. The intent of Sentence 9.8.7.1.(2) is that handrails be installed in relation to the

required stair

width only, regardless of the actual width of the stair and ramp. The required handrails are provided along the assumed

natural path of travel to, from

and within the building.

A-9.8.7.2. Continuity of Handrails. The guidance and support provided by handrails is particularly important at the

beginning and end of ramps and flights of stairs and at changes in direction such as at landings and winders.

The intent of the requirement in Sentence (2) for handrails to be continuous throughout the length of the stair is that the handrail be

continuous from the bottom riser to the top riser of the stair. (See Figure A-9.8.7.2.)

For stairs or ramps serving a single dwelling unit, the intent of the requirement for handrails to be continuous throughout the length of

the flight is that the handrail be continuous from the bottom riser to the top riser of the flight. The required handrail may start back

from the bottom riser only if it is supported by a newel post or volute installed on the bottom tread. (See Figure A-9.8.7.2.)

With regard to stairs serving a single dwelling unit, the handrail may terminate at landings.

In the case of stairs within dwelling units that incorporate winders, the handrail should be configured so that it will in fact provide

guidance and support to the stair user throughout the turn through the winder.

200

150

200

min

255

min

255

155

200

30°

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.8.7.2.

Continuity of handrails at the top and bottom of stairs and flights

Note to Figure A-9.8.7.2.:

(1) See Article 9.8.7.1. to determine the number of handrails required. Some stairs will require only one, while some will require two or more.

A-9.8.7.3.(1) Termination of Handrails. Handrails are required to be installed so as not to obstruct pedestrian travel.

To achieve this end, the rail should not extend so far into a hallway as to reduce the clear width of the hallway to less than the required

width. Where the stair terminates in a room or other space, likely paths of travel through that room or space should be assessed to

ensure that any projection of the handrail beyond the end of the stair will not interfere with pedestrian travel. As extensions of

handrails beyond the first and last riser are not required in dwelling units (see Sentence 9.8.7.3.(2)) and as occupants of dwellings are

generally familiar with their surroundings, the design of dwellings would not generally be affected by this requirement.

Handrails are also required to terminate in a manner that will not create a safety hazard to blind or visually impaired persons, children

whose heads may be at the same height as the end of the rail, or persons wearing loose clothing or carrying items that might catch on

the end of the rail. One approach to reducing potential hazards is returning the handrail to a wall, floor or post. Again, within dwelling

units, where occupants are generally familiar with their surroundings, returning the handrail to a wall, floor or post may not be

necessary. For example, where the handrail is fastened to a wall and does not project past the wall into a hallway or other space,

a reasonable degree of safety is assumed to be provided; other alternatives may provide an equivalent level of protection.

A-9.8.7.3.(2) Handrail Extensions. As noted in Note A-9.8.7.2., the guidance and support provided by handrails is

particularly important at the beginning and end of ramps and flights of stairs and at changes in direction. The extended handrail

provides guidance and allows users to steady themselves upon entering or leaving a ramp or flight of stairs. Such extensions are

particularly useful to visually-impaired persons, and persons with physical disabilities or who are encumbered in their use of the stairs

or ramp.

(b) Stair serving a single dwelling unit

or a house with a secondary suite

(including their common spaces):

handrails continuous through length

of flight

winders are part of a stair flight and

are not considered a change in

direction

See NBC Article 9.8.7.1. to determine

the number of handrails required.

Some stairs will require only one

while some will require two or more.

(a) Stair serving other than a single dwelling

unit or a house with a secondary suite

(including their common spaces): handrails

continuous through length of stair

interruption

permitted

at door

interruption permitted at

door and at newel posts

at changes in direction

interruption permitted at

landing and at newel posts

at changes in direction

minimum extent of handrail where handrail

is required

newel post

top top

top

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.8.7.4. Height of Handrails. Figure A-9.8.7.4. illustrates how to measure handrail height.

Figure A-9.8.7.4.

Measuring handrail height

A-9.8.7.5.(2) Handrail Sections. Handrails are intended to provide guidance and support to stair users. To fulfil this intent,

handrails must be “graspable.”

The graspable portion of a handrail should allow a person to comfortably and firmly grab hold by allowing their fingers and thumb to

curl under part or all of the handrail. Where the configuration or dimensions of the handrail do not allow a person’s fingers and thumb

to reach the bottom of it, recesses that are sufficiently wide and deep to accommodate a person’s fingers and thumb must be provided

on both sides of the handrail, at the bottom of the graspable portion, which must not have any sharp edges.

A-9.8.7.7. Attachment of Handrails. Handrails are intended to provide guidance and support to the stair user and to arrest

falls. The loads on handrails may therefore be considerable. The attachment of handrails serving a single dwelling unit may be accepted

on the basis of experience or structural design.

A-9.8.8.1. Required Guards. The requirements relating to guards stated in Part 9 are based on the premise that, wherever

there is a difference in elevation of 600 mm or more between two floors, or between a floor or other surface to which access is provided

for other than maintenance purposes and the next lower surface, the risk of injury in a fall from the higher surface is sufficient to

warrant the installation of some kind of barrier to reduce the chances of such a fall. A wall along the edge of the higher surface will

obviously prevent such a fall, provided the wall is sufficiently strong that a person cannot fall through it. Where there is no wall, a

guard must be installed. Because guards clearly provide less protection than walls, additional requirements apply to guards to ensure

that a minimum level of protection is provided. These relate to the characteristics described in Notes A-9.8.8.3., A-9.8.8.5.(1) and (2),

A-9.8.8.5.(3) and A-9.8.8.6.(1).

Examples of such surfaces where the difference in elevation could exceed 600 mm and consequently where guards would be required

include, but are not limited to, landings, porches, balconies, mezzanines, galleries, and raised walkways. Especially in exterior settings,

surfaces adjacent to walking surfaces, stairs or ramps often are not parallel to the walking surface or the surface of the treads or ramps.

Consequently, the walking surface, stair or ramp may need protection in some locations but not in others. (See Figure A-9.8.8.1.)

In some instances, grades are artificially raised close to walking surfaces, stairs or ramps to avoid installing guards. This provides little

or no protection for the users. That is why the requirements specify differences in elevation not only immediately adjacent to the

construction but also for a distance of 1200 mm from it by requiring that the slope of the ground be within certain limits.

(See Figure A-9.8.8.1.)

EG00322B

handrail

vertical

measurement

of height

straight line tangent

to tread nosing

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.8.8.1.

Required locations of guards

A-9.8.8.1.(4) Height of Window Sills above Floors or Ground. The primary intent of the requirement is to minimize

the likelihood of small children falling significant heights from open windows. Reflecting reported cases, the requirement applies only

to dwelling units and generally those located on the second floor or higher of residential or mixed use buildings where the windows are

essentially free-swinging or free-sliding.

Free-swinging or free-sliding means that a window that has been cracked open can be opened further by simply pushing on the

openable part of the window. Care must be taken in selecting windows, as some with special operating hardware can still be opened

further by simply pushing on the window.

Casement windows with crank operators would be considered to conform to Clause (4)(b). To provide additional safety, where slightly

older children are involved, occupants can easily remove the crank handles from these windows. Awning windows with scissor

hardware, however, may not keep the window from swinging open once it is unlatched. Hopper windows would be affected only if an

opening is created at the bottom as well as at the top of the window. The requirement will impact primarily on the use of sliding

windows which do not incorporate devices in their construction that can be used to limit the openable area of the window.

The 100 mm opening limit is consistent with widths of openings that small children can fall through. It is only invoked, however,

where the other dimension of the opening is more than 380 mm. Again, care must be taken in selecting a window. At some position,

scissor hardware on an awning window may break up the open area such that there is no unobstructed opening with dimensions

greater than 380 mm and 100 mm. At another position, however, though the window is not open much more, the hardware may not

adequately break up the opening. The 450 mm height off the floor recognizes that furniture is often placed under windows and small

children are often good climbers.

A-9.8.8.2. Loads on Guards. Guards must be constructed so as to be strong enough to protect persons from falling under

normal use. Many guards installed in dwelling units or on exterior stairs serving one or two dwelling units have demonstrated

acceptable performance over time. The loading described in the first row of Table 9.8.8.2. is intended to be consistent with the

performance provided by these guards. Examples of guard construction presented in the “2012 Building Code Compendium,

Volume 2, Supplementary Standard SB-7, Guards for Housing and Small Buildings” meet the criteria set in the National Building

Code for loads on guards, including the more stringent requirements of Sentences 9.8.8.2.(1) and (2).

The load on guards within dwelling units, or on exterior guards serving not more than two dwelling units, is to be imposed over an

area of the guard such that, where standard balusters are used and installed at the maximum 100 mm spacing permitted for required

guards, 3 balusters will be engaged. Where the balusters are wider, only two may be engaged unless they are spaced closer together.

Where the guard is not required, and balusters are installed more than 100 mm apart, fewer balusters may be required to carry the

imposed load.

A-9.8.8.3. Minimum Heights. Guard heights are generally based on the waist heights of average persons. Generally, lower

heights are permitted in dwelling units because the occupants become familiar with the potential hazards, and situations which lead to

pushing and jostling under crowded conditions are less likely to arise.

A-9.8.8.5.(1) and (2) Risk of Falling through Guards. The risk of falling through a guard is especially prevalent for

children. Therefore the requirements are stringent for guards in all buildings except industrial buildings, where children are unlikely

to be present except under strict supervision.

600 mm

1 200 mm

slope is greater

than 1 in 2

EG02058A

handrail

required

guard required

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.8.8.5.(3) Risk of Children Getting Their Head Stuck between Balusters. The requirements to prevent children

falling through guards also serve to provide adequate protection against this problem. However, guards are often installed where they

are not required by the Code; i.e., in places where the difference in elevation is less than 600 mm. In these cases, there is no need to

require the openings between balusters to be less than 100 mm. However, there is a range of openings between 100 mm and 200 mm

in which children can get their head stuck. Therefore, openings in this range are not permitted except in buildings of industrial

occupancy, where children are unlikely to be present except under strict supervision.

A-9.8.8.6.(1) Configuration of Members, Attachments or Openings in Guards so as to not Facilitate

Climbing. Some configurations of members, attachments or openings may be part of a guard design and still comply with

Sentence 9.8.8.6.(1). Figures A-9.8.8.6.(1)-A to A-9.8.8.6.(1)-D present a few examples of designs that are considered to not

facilitate climbing.

Protrusions that are greater than 450 mm apart horizontally and vertically are considered sufficiently far apart to reduce the likelihood

that young children will be able to get a handhold or toehold on the protrusions and climb the guard.

Figure A-9.8.8.6.(1)-A

Example of minimum horizontal and vertical clearances between protrusions in guards

Protrusions that present a horizontal offset of 15 mm or less are considered to not provide a sufficient foot purchase to

facilitate climbing.

> 450 mm

900 mm

140 mm

GG00176A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.8.8.6.(1)-B

Examples of maximum horizontal offset of protrusions in guards

A guard incorporating spaces that are not more than 45 mm wide by 20 mm high is considered to not facilitate climbing because the

spaces are too small to provide a toehold.

Figure A-9.8.8.6.(1)-C

Example of a guard with spaces created by the protruding elements that are not more than 45 mm wide and 20 mm high

EG00746A

≤15 mm offset

900 mm

140 mm

900 mm

140 mm

≤ 45 mm

≤ 20 mm

GG00178A

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Protrusions that present more than a 2-in-1 slope on the offset are considered to not facilitate climbing because such a slope is

considered too steep to provide adequate footing.

Figure A-9.8.8.6.(1)-D

Example of guard protrusions with a slope greater than 2 in 1

A-9.9.4.5.(1) Openings in Exterior Walls of Exits.

Figure A-9.9.4.5.(1)

Protection of openings in exterior walls of exits

> 2

GG00179A

900 mm

140 mm

• > 3 m horizontally

• opening in building > 2 m

above openings in the exit

³ 135˚

< 135˚

no protection

required

no protection

required

openings within 3 m horizontally and

within 2 m above openings in the exit

< 135˚

protection

required

protection

required

EC01221A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.9.8.4.(1) Independent and Remote Exits. Subsection 9.9.8. requires that some floor areas have more than one exit.

The intent is to ensure that, if one exit is made untenable or inaccessible by a fire, or its exterior door is blocked by an exterior

incident, one or more other exits will be available to permit the occupants to escape. However, if the exits are close together, all exits

might be made untenable or inaccessible by the same fire. Sentence 9.9.8.4.(1) therefore requires at least two of the exits to be located

remotely from each other. This is not a problem in many buildings falling under Part 9. For instance, apartment buildings usually have

exits located at either end of long corridors. However, in other types of buildings (e.g. dormitory and college residence buildings)

this is often difficult to accomplish and problems arise in interpreting the meaning of the word “remote.” Article 3.4.2.3. is more

specific, generally requiring the distance between exits to be one half the diagonal dimension of the floor area or at least 9 m. However,

it is felt that such criteria would be too restrictive to impose on the design of all the smaller buildings which come under Part 9.

Nevertheless, the exits should be placed as far apart as possible and the Part 3 criteria should be used as a target. Designs in which the

exits are so close together that they will obviously both become contaminated in the event of a fire are not acceptable.

A-9.9.10.1.(1) Escape Windows from Bedrooms. Sentence 9.9.10.1.(1) generally requires every bedroom in an

unsprinklered suite to have at least one window or door opening to the outside that is large enough and easy enough to open so that it

can be used as an exit in the event that a fire prevents use of the building’s normal exits. The minimum unobstructed opening specified

for escape windows must be achievable using only the normal window operating procedure. The escape path must not go through nor

open onto another room, floor or space.

Where a bedroom is located in an unsprinklered suite in a basement, an escape window or door must be located in the bedroom. It is

not sufficient to rely on egress through other basement space to another escape window or door.

Window Height

The Article does not set a maximum sill height for escape windows; it is therefore possible to install a window or skylight that

satisfies the requirements of the Article but defeats the Article’s intent by virtue of being so high that it cannot be reached for exit

purposes. It is recommended that the sills of windows intended for use as emergency exits be not higher than 1.5 m above the

floor. However, it is sometimes difficult to avoid having a higher sill: on skylights and windows in basement bedrooms for

example. In these cases, it is recommended that access to the window be improved by some means such as built-in furniture

installed below the window.

Figure A-9.9.10.1.(1)

Built-in furniture to improve access to a window

EC00319B

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.9.10.1.(2) Bedroom Window Opening Areas and Dimensions. Although the minimum opening dimensions

required for height and width are 380 mm, a window opening that is 380 mm by 380 mm would not comply with the minimum area

requirements. (See Figure A-9.9.10.1.(2))

Figure A-9.9.10.1.(2)

Window opening areas and dimensions

A-9.9.10.1.(3) Window Opening into a Window Well. Sentence 9.9.10.1.(3) specifies that there must be a minimum

clearance of 760 mm in front of designated escape windows to allow persons to escape a basement bedroom in an emergency.

This specified minimum clearance is consistent with the minimum required width for means of egress from a floor area

(see Article 9.9.5.5.) and the minimum required width for path of travel on exit stairs (see Article 9.9.6.1.). It is considered the

smallest acceptable clearance between the escape window and the facing wall of the window well that can accommodate persons trying

to escape a bedroom in an emergency given that they are not moving straight through the window but must move outward and up,

and must have sufficient space to change body orientation.

Once this clearance is provided, no additional clearance is needed for windows with sliders, casements, or inward-opening awnings.

However, for windows with outward-opening awnings, additional clearance is needed to provide the required 760 mm beyond the

outer edge of the sash. (See Figure A-9.9.10.1.(3).)

Depending on the likelihood of snow accumulation in the window well, it could be difficult – if not impossible – to escape in an

emergency. The window well should be designed to provide sufficient clear space for a person to get out the window and then out the

well, taking into account potential snow accumulation.

Hopper windows (bottom-hinged operators) should not be used as escape windows in cases where the occupants would be required to

climb over the glass.

(a) conforms to opening height

and width requirements; does

not conform to opening area

requirements

(b) and (c) conform to height, width and

opening area requirements

380 mm

Opening

area

0.144 m

(a)

380 mm

920 mm

Opening

area

0.35 m

(b)

EG00318B

592 mm

Opening

area

0.35 m

(c)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.9.10.1.(3)

Windows providing a means of escape that open into a window well

A-9.10.1.4.(1) Commercial Cooking Equipment. Part 6 refers to NFPA 96, “Ventilation Control and Fire Protection of

Commercial Cooking Operations,” which in turn references “Commercial Cooking Equipment.” However, the deciding factor as to

whether or not NFPA 96 applies is the potential for production of grease-laden vapours and smoke, rather than the type of equipment

used. While NFPA 96 does not apply to domestic equipment for normal residential family use, it should apply to domestic equipment

used in commercial, industrial, institutional and similar cooking applications where the potential for the production of smoke and

grease-laden vapours exceeds that for normal residential family use.

A-9.10.3.1. Fire and Sound Resistance of Building Assemblies. Tables 9.10.3.1.-A and 9.10.3.1.-B have been

developed from information gathered from tests. While a large number of the assemblies listed were tested, the fire-resistance and

acoustical ratings for others were assigned on the basis of extrapolation of information from tests of similar assemblies. Where there

was enough confidence relative to the fire performance of an assembly, the fire-resistance ratings were assigned relative to the

commonly used minimum ratings of 30 min, 45 min and 1 h, including a designation of “< 30 min” for assemblies that are known

not to meet the minimum 30-minute rating. Where there was not enough comparative information on an assembly to assign to it a

rating with confidence, its value in the tables has been left blank (hyphen), indicating that its rating remains to be assessed through

another means. Future work is planned to develop much of this additional information.

These tables are provided only for the convenience of Code users and do not limit the number of assemblies permitted to those in the

tables. Assemblies not listed or not given a rating in these tables are equally acceptable provided their fire and sound resistance can be

demonstrated to meet the above-noted requirements either on the basis of tests referred to in Article 9.10.3.1. and Subsection 9.11.1.

or by using the data in Appendix D, Fire-Performance Ratings. It should be noted, however, that Tables 9.10.3.1.-A and 9.10.3.1.-B

are not based on the same assumptions as those used in Appendix D. Assemblies in Tables 9.10.3.1.-A and 9.10.3.1.-B are described

through their generic descriptions and variants and include details given in the notes to the tables. Assumptions for Appendix D

include different construction details that must be followed rigorously for the calculated ratings to be expected. These are two different

methods of choosing assemblies that meet required fire ratings.

Table 9.10.3.1.-B presents fire-resistance and acoustical ratings for floor, ceiling and roof assemblies. The fire-resistance ratings are

appropriate for all assemblies conforming to the construction specifications given in Table 9.10.3.1.-B, including applicable table

notes. Acoustical ratings for assemblies decrease with decreasing depth and decreasing separation of the structural members; the values

listed for sound transmission class and impact insulation class are suitable for the minimum depth of structural members identified in

the description, including applicable table notes, and for structural member spacing of 305 mm o.c., unless other values are explicitly

listed for the assembly. Adjustments to the acoustical ratings to allow for the benefit of deeper or more widely spaced structural

members are given in Table Notes (9) and (10).

EG00688A

760

grade

basement

760

basement

window

well

760 mm

window

well

grade

window

well

grade

basement

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.10.3.1.-A

Single layer butt joint details

Notes to Figure A-9.10.3.1.-A:

(1) Figure is for illustrative purposes only and is not to scale.

(2) The structural member can be any one of the types described in the Table.

(3) Adjacent gypsum board butt ends are attached to separate resilient channels using regular Type S screws, located a minimum of 38 mm from

the butt end.

Figure A-9.10.3.1.-B

Double layer butt joint details

Notes to Figure A-9.10.3.1.-B:

(1) Figure is for illustrative purposes only and is not to scale.

(2) The structural member can be any one of the types described in the Table.

(3) Base layer butt ends can be attached to a single resilient channel using regular Type S screws.

(4) Type G screws measuring a minimum of 32 mm in length and located a minimum of 38 mm from the butt end are used to fasten the butt ends

of the face layer to the base layer.

Figure A-9.10.3.1.-C

Example of steel furring channel

Note to Figure A-9.10.3.1.-C:

(1) Figure is for illustrative purposes only and is not to scale.

GG00160A

GG00161A

GG00172A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.10.3.1.-D

Example of resilient metal channel

Note to Figure A-9.10.3.1.-D:

(1) Figure is for illustrative purposes only and is not to scale.

A-9.10.4.1.(4) Mezzanines Not Considered as Storeys. Mezzanines increase the occupant load and the fire load of the

storey of which they are part. To take the added occupant load into account for the purpose of evaluating other requirements that are

dependent on this criteria, their floor area is added to the floor area of the storey.

A-9.10.9.6.(1) Penetration of Fire-Rated Assemblies by Service Equipment. This Sentence, together with

Article 3.1.9.1., is intended to ensure that the integrity of fire-rated assemblies is maintained where they are penetrated by various

types of service equipment.

For buildings regulated by the requirements in Part 3, fire stop materials used to seal openings around building services, such as pipes,

ducts and electrical outlet boxes, must meet a minimum level of performance demonstrated by standard test criteria.

This is different from the approach in Part 9. Because of the type of construction normally used for buildings regulated by the

requirements in Part 9, it is assumed that this requirement is satisfied by the use of generic fire stop materials such as mineral wool,

gypsum plaster or Portland cement mortar.

A-9.10.9.16.(4) Separation between Dwelling Units and Storage or Repair Garages. The gas-tight barrier

between a dwelling unit and an attached garage is intended to provide protection against the entry of carbon monoxide and gasoline

fumes into the dwelling unit. Building assemblies incorporating an air barrier system will perform adequately with respect to gas

tightness, provided all joints in the airtight material are sealed and reasonable care is exercised where the wall or ceiling is pierced by

building services. Where a garage is open to the adjacent attic space above the dwelling unit it serves, a gas-tight barrier in the ceiling of

the dwelling unit will also provide protection. Unit masonry walls forming the separation between a dwelling unit and an adjacent

garage should be provided with two coats of sealer or plaster, or covered with gypsum board on the side of the wall exposed to the

garage. All joints must be sealed to ensure continuity of the barrier. (See also Sentences 9.25.3.3.(3) to (8).)

GG00173A

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.10.12.4.(1) Protection of Overhang of Common Roof Space.

Figure A-9.10.12.4.(1)

Protection of overhang of common roof space

A-9.10.12.4.(3) Protection at Soffits. The materials required by this Sentence to be used as protection for soffit spaces in

certain locations do not necessarily have to be the finish materials. They can be installed either behind the finishes chosen for the soffits

or in lieu of these.

A-9.10.13.2.(1) Wood Doors in Fire Separations. CAN/ULC-S113, “Wood Core Doors Meeting the Performance

Required by CAN/ULC-S104 for Twenty Minute Fire Rated Closure Assemblies,” provides construction details to enable

manufacturers to build wood core doors that will provide a 20 min fire-protection rating without the need for testing. The standard

requires each door to be marked with

1. the manufacturer’s or vendor’s name or identifying symbol,

2. the words “Fire Door,” and

3. a reference to the fire-protection rating of 20 min.

A-9.10.14.5.(1) Minor Combustible Cladding Elements. Minor elements of cladding that is required to be

noncombustible are permitted to be of combustible material, provided they are distributed over the building face and not concentrated

in one area. Examples of minor combustible cladding elements include door and window trim and some decorative elements.

A-9.10.14.5.(7) Permitted Projections. The definition of exposing building face provided in Sentence 1.4.1.2.(1) of

Division A refers to “that part of the exterior wall of a building … or, where a building is divided into fire compartments, the exterior

wall of a fire compartment …” Because the exposing building face is defined with respect to the exterior wall, projections from

exposing building faces are elements that do not incorporate exterior walls. Depending on their specific configurations, examples of

constructions that would normally be permitted by Sentence 9.10.14.5.(7) are balconies, platforms, canopies, eave projections and

stairs. However, if a balcony, platform or stair is enclosed, its exterior wall would become part of an exposing building face and the

construction could not be considered to be a projection from the exposing building face.

1.2 m

area to be protected

2.5 m

or less

EC00357B

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.10.14.5.(8) Protection at Projections. Sentence 9.10.14.5.(7) permits certain projections from exposing building faces

where the projections do not have exterior walls and thus clearly do not constitute part of the exposing building face.

Sentence 9.10.14.5.(8) refers to other types of projections from the exposing building face, such as those for fireplaces and chimneys.

It is recognized that these types present more vertical surface area compared to platforms, canopies and eave projections, and may be

enclosed by constructions that are essentially the same as exterior walls. These constructions, however, do not enclose habitable space,

are of limited width and may not extend a full storey in height. Consequently, Sentence (8) allows these projections beyond the

exposing building face of buildings identified in Sentence (6), provided additional fire protection is installed on the projection.

Figure A-9.10.14.5.(8) illustrates projections that extend within 1.2 m of the property line where additional protection must be

provided. Where a projection extends within 0.6 m of the property line, it must be protected to the same degree as an exposing

building face that has a limiting distance of less than 0.6 m. Where a projection extends to less than 1.2 m but not less than 0.6m of

the property line, it must be protected to the same degree as an exposing building face that has a limiting distance of less than 1.2 m.

Protection is also required on the underside of the projection where the projection is more than 0.6 m above finished ground level,

measured at the exposing building face.

Figure A-9.10.14.5.(8)

Protection at projections

EG00694D

space

enclosed by

projection is

not habitable

space

enclosed by

projection is

not habitable

space

enclosed by

projection is

not habitable

space

> 0.6 m

< 1.2 m

Section

PlanPlan

normal cladding-sheathing assembly

cladding-sheathing assemblies

providing additional fire protection

}

< 1.2 m

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.10.14.5.(11) and 9.10.15.5.(10) Roof Soffit Projections.

Figure A-9.10.14.5.(11) and 9.10.15.5.(10)

Roof soffit projections

Notes to Figure A-9.10.14.5.(11) and 9.10.15.5.(10):

(1) See Sentences 3.2.3.6.(2), 9.10.14.5.(9) and 9.10.15.5.(8).

(2) See Sentences 3.2.3.6.(3), 9.10.14.5.(10) and 9.10.15.5.(9).

(3) See Sentences 3.2.3.6.(4), 9.10.14.5.(11) and 9.10.15.5.(10).

A-9.10.15.4.(2) Staggered or Skewed Exposing Building Faces of Houses. Studies at the National Fire Laboratory

of the National Research Council have shown that, where an exposing building face is stepped back from the property line or is at an

angle to the property line, it is possible to increase the percentage of glazing in those portions of the exposing building face further

from the property line without increasing the amount of radiated energy that would reach the property line in the event of a fire in

such a building. Figures A-9.10.15.4.(2)-A, A-9.10.15.4.(2)-B and A-9.10.15.4.(2)-C show how Sentences 9.10.15.4.(1) and (2),

and 9.10.15.5.(2) and (3) can be applied to exposing building faces that are stepped back from or not parallel to the property line.

The following procedure can be used to establish the maximum permitted area of glazed openings for such facades:

1. Calculate the total area of the exposing building face, i.e. facade of the fire compartment, as described in the definition of

exposing building face.

2. Identify the portions into which the exposing building face is to be divided. It can be divided in any number of portions, not

necessarily of equal size.

3. Measure the limiting distance for each portion. The limiting distance is measured along a line perpendicular to the wall surface

from the point closest to the property line.

4. Establish the line in Table 9.10.15.4. from which the maximum permitted percentage area of glazed openings will be read.

The selection of the line depends on the maximum area of exposing building face for the whole fire compartment, including all

portions, as determined in Step 1.

5. On that line, read the maximum percentage area of glazed openings permitted in each portion of the exposing building face

according to the limiting distance for that portion.

a) Projecting roof soffit not

allowed to be constructed

(1)

b) Roof soffit must not project to

less than 0.45 m from the

property line

(2)

c) Roof soffit permitted to project up to

property line, where it faces a

street, lane or public thoroughfare,

regardless of the limiting distance

(3)

no roof

soffits

≥ 0.45 m

LD ≤ 0.45 m

LD > 0.45 m

property line

centre line of a street, lane or public thoroughfare

property line

EG01393A

LD = limiting distance

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

6. Calculate the maximum area of glazed openings permitted in each portion. The area is calculated from the percentage found

applied to the area of that portion.

Table 9.10.15.4. is used to read the maximum area of glazed openings: this means that the opaque portion of doors does not have to be

counted as for other types of buildings.

Note that this Note and the Figures do not describe or illustrate maximum permitted concentrated area or spacing of individual glazed

openings, or limits on the location of dividing lines between portions of the exposing building face depending on the location of these

openings with respect to interior rooms or spaces. See Sentences 9.10.15.2.(2) and 9.10.15.4.(2) to (4) for the applicable

requirements.

Figure A-9.10.15.4.(2)-A

Example of determination of criteria for the exposing building face of a staggered wall of a house

Notes to Figure A-9.10.15.4.(2)-A:

(1) See Sentence 9.10.15.5.(2).

(2) See Sentence 9.10.15.5.(3).

(3) See Table 9.10.15.4., Subclause 9.10.15.2.(1)(b)(iii) and Sentence 9.10.15.4.(2).

noncombustible no limits

0% 7% 1 1 %

7.6 m 6 m 3 m

required not required

no limits

not required

3 x 2.4 x 0.07

= 0.50 m

6 x 2.4 x 0. 1 1 = 1.58 m

EG00417D

Permitted aggregate

area of glazed openings

Permitted % of

glazed openings

Type of cladding

45 min fire-resistance

rating

Property Line

Exposing

Building Face:

- T otal length: 16.6 m

- Height: 2.4 m

- T otal area:

16.6 x 2.4 = 40 m

limiting distance

= 0.4 m

limiting distance

= 1.2 m

limiting distance

= 2.0 m

(1)

(2) (2)

(2)

(3)

(1)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.10.15.4.(2)-B

Example of determination of criteria for the exposing building face of a skewed wall of a house with some arbitrary division of the wall

Notes to Figure A-9.10.15.4.(2)-B:

(1) See Sentence 9.10.15.5.(2).

(2) See Sentence 9.10.15.5.(3).

(3) See Table 9.10.15.4., Subclause 9.10.15.2.(1)(b)(iii) and Sentence 9.10.15.4.(2).

(4) To simplify the calculations, choose the column for the lesser limiting distance nearest to the actual limiting distance. Interpolation for limiting

distance is also acceptable and may result in a slightly larger permitted area of glazed openings. Interpolation can only be used for limiting

distances greater than 1.2 m.

required required not required not required

not required

no limits no limits no limits noncombustible

noncom-

bustible

0% 100% 28%9%0%

0 0 5.0 x 2.4 x 0.09

= 1.08 m

7.0 x 2.4 x 0.28

= 4.70 m

3.0 x 2.4 x 1.0

= 7.2 m

EG00378D

Permitted aggregate

area of glazed openings

Permitted % of

glazed openings

Type of cladding

45 min fire-resistance

rating

3.8 m

30°

Property Line

Exposing

Building Face:

- T otal length: 20.8 m

- Height: 2.4 m

T otal area:

20.8 x 2.4 = 50 m

limiting distance

= 0.5 m

limiting

distance

= 0.58 m

limiting

distance

= 1.73 m

limiting

distance

= 4.62 m

limiting

distance

= 8.66 m

5.0 m

7.0 m

3.0 m

2.0 m

(2) (2) (2)

(3)(4)

(1) (1) (2) (2)

(2)

(1)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.10.15.4.(2)-C

Example of determination of criteria for the exposing building face of a skewed wall of a house with a different arbitrary division of

the wall

Notes to Figure A-9.10.15.4.(2)-C:

(1) See Sentence 9.10.15.5.(2).

(2) See Sentence 9.10.15.5.(3).

(3) See Table 9.10.15.4., Subclause 9.10.15.2.(1)(b)(iii) and Sentence 9.10.15.4.(2).

(4) To simplify the calculations, choose the column for the lesser limiting distance nearest to the actual limiting distance. Interpolation for limiting

distance is also acceptable and may result in a slightly larger permitted area of glazed openings. Interpolation can only be used for limiting

distances greater than 1.2 m.

A-9.10.19.3.(1) Location of Smoke Alarms. There are two important points to bear in mind when considering where to

locate smoke alarms in dwelling units:

• The most frequent point of origin for fires in dwelling units is the living area.

• The main concern in locating smoke alarms is to provide warning to people asleep in bedrooms.

A smoke alarm located in the living area and wired so as to sound another smoke alarm located near the bedrooms is the ideal solution.

However, it is difficult to define exactly what is meant by “living area.” It is felt to be too stringent to require a smoke alarm in every

part of a dwelling unit that could conceivably be considered a “living area” (living room, family room, study, etc.).

Sentence 9.10.19.3.(1) addresses these issues by requiring at least one smoke alarm on every storey containing a sleeping room.

Thus, in a dwelling unit complying with Sentence 9.10.19.3.(1), every living area will probably be located within a reasonable distance

of a smoke alarm. Nevertheless, where a choice arises as to where on a storey to locate the required smoke alarm or alarms, one should

be located as close as possible to a living area, provided the requirements related to proximity to bedrooms are also satisfied.

A smoke alarm is not required on each level in a split-level dwelling unit as each level does not count as a separate storey. Determine the

number of storeys in a split-level dwelling unit and which levels are part of which storey as follows:

1. establish grade, which is the lowest of the average levels of finished ground adjoining each exterior wall of a building;

2. identify the first storey, which is the uppermost storey having its floor level not more than 2 m above grade;

required

noncom-

bustible

3.8 m

9.0 m

5.0 m

2.0 m

0% 7%

Permitted aggregate

area of glazed openings

Permitted % of

glazed openings

Type of cladding

45 min fire-resistance

rating

Property Line

Exposing

Building Face:

- T otal length: 20.8 m

- Height: 2.4 m

- T otal area:

20.8 x 2.4 = 50 m

limiting distance

= 0.54 m

limiting distance

= 0.62 m

limiting

distance

= 6.4 m

limiting

distance

= 9.3 m

limiting distance

= 1.2 m

required

no limits no limits

not required

no limits

not required

9.0 x 2.4 x 0.07

= 1.51 m

5.0 x 2.4 x 0.57

= 6.84 m

2.0 x 2.4 x 1.0

57%

EG00379D

30°

100%

1.0 m

= 4.8 m

(2)

(1)

(2)

(2) (2)

(1)

(3)(4)

noncombustible

(2)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

3. identify the basement, which is the storey or storeys located below the first storey;

4. identify the second storey and, where applicable, the third storey.

As a minimum, one smoke alarm is required to be installed in each storey, preferably on the upper level of each one. As noted above,

however, when the dwelling unit contains more than one sleeping area, an alarm must be installed to serve each area. Where the

sleeping areas are on two levels of a single storey in a split-level dwelling unit, an additional smoke alarm must be installed so that both

areas are protected. See Figure A-9.10.19.3.(1).

Figure A-9.10.19.3.(1)

Two-storey split-level building

Notes to Figure A-9.10.19.3.(1):

(1) One smoke alarm required for each of the basement, first storey and second storey.

(2) An additional smoke alarm is required on the lower level of the second storey outside the sleeping rooms.

A-9.10.20.3.(1) Fire Department Access Route Modification. In addition to other considerations taken into account in

the planning of fire department access routes, special variations could be permitted for a house or residential building that is protected

with an automatic sprinkler system. The sprinkler system must be designed in accordance with the appropriate NFPA standard and

there must be assurance that water supply pressure and quantity are unlikely to fail. These considerations could apply to buildings that

are located on the sides of hills and are not conveniently accessible by roads designed for firefighting equipment and also to infill

housing units that are located behind other buildings on a given property.

A-9.10.22. Clearances from Gas, Propane and Electric Cooktops. CSA C22.1, “Canadian Electrical Code, Part I,”

which is adopted by the Electrical Safety Regulation

referenced in Article 9.34.1.1., and CSA B149.1, “Natural Gas and Propane

Installation Code,” which is adopted by the Gas Safety Regulation

referenced in Article 9.10.22.1., address clearances directly above,

in front of, behind and beside the appliance. Where side clearances are zero, the standards do not address clearances to building

elements located both above the level of the cooktop elements or burners and to the side of the appliance. Through reference to the

above noted regulations and their adopted standards

, and the requirements in Articles 9.10.22.2. and 9.10.22.3., the British Columbia

Building Code addresses all clearances. Where clearances are addressed by the British Columbia Building Code and the above noted

regulations and their adopted standards, conformance with all relevant criteria is achieved by compliance with the most

stringent criteria.

EG00676A

Not more

than 2 m

(1)

(2)

Grade

Lower 2nd storey

(with sleeping area)

Lower 1st storey

Lower basement

Upper 2nd storey

(with sleeping area)

Upper 1st storey

Upper

basement

= smoke alarm

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Installation of Microwave Ovens Over Cooktops

The minimum vertical clearances stated in Article 9.10.22.2. apply only to combustible framing, finishes and cabinets. They do

not apply to microwave ovens installed over cooktops nor to range hoods. The “Canadian Electrical Code, Part I” requires that

microwave ovens comply with CAN/CSA-C22.2 No. 150, “Microwave Ovens.” This standard includes tests to confirm that the

appliance will not present a hazard when installed according to the manufacturer’s instructions.

Figure A-9.10.22.

Clearances from cooktops to walls and cabinetry

appliance opening

horizontal or

vertical clearance

less than 450 mm -

protected

EG00380A

vertical clearance 600 mm minimum -

protected or noncombustible;

750 mm or more - unprotected

horizontal or

vertical clearance

450 mm or more -

unprotected

level of elements

or burners

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.11. Sound Transmission.

Airborne Sound

Airborne sound is transmitted between adjoining spaces directly through the separating wall, floor and ceiling assemblies and via

the junctions between these separating assemblies and the flanking assemblies.

The Sound Transmission Class (STC) rating describes the performance of the separating wall or floor/ceiling assembly, whereas

the Apparent Sound Transmission Class (ASTC) takes into consideration the performance of the separating element as well as the

flanking transmission paths. Therefore, from the occupants’ point of view, the best indicator of noise protection between two

spaces is the ASTC rating.

As a key principle, it is important to follow a “whole-system” approach when designing or constructing assemblies that separate

dwelling units because the overall sound performance of walls and floors is also influenced by fire protection measures and the

structural design of the assemblies. Likewise, changes to the construction of assemblies to meet sound transmission requirements

may have fire and structural implications. Another key principle is that enhancing the performance of the separating element does

not automatically enhance the system’s performance.

For horizontally adjoining spaces, the separating assembly is the intervening wall and the pertinent flanking surfaces include those

of the floor, ceiling, and side wall assemblies that have junctions with the separating wall assembly, normally at its four edges.

For each of these junctions, there is a set of sound transmission paths. Figure A-9.11.-A illustrates the horizontal sound

transmission paths at the junction of a separating wall with flanking floor assemblies.

Figure A-9.11.-A

Horizontal sound transmission paths at floor/wall junction

For vertically adjoining spaces, the separating assembly is the intervening floor/ceiling and the pertinent flanking surfaces include

those of the side wall assemblies in the upper and lower rooms that have junctions with the separating floor/ceiling assembly at its

edges, of which there are normally four. For each of these junctions, there is a set of sound transmission paths. Figure A-9.11.-B

illustrates the vertical sound transmission paths at the junction of a separating floor/ceiling assembly with two flanking wall

assemblies.

EG01379A

apparent

sound

transmission

class (ASTC)

direct path

(STC)

flanking paths

airborne

sound

source

flanking

floor/ceiling

assembly

separating wall assembly

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.11.-B

Vertical sound transmission paths at wall/floor junction

Control of Sound Leaks

The metrics used to characterize the sound transmission performance of assemblies separating dwelling units do not account for

the adverse effects of air leaks in those assemblies, which can transfer sound. Sound leaks can occur where a wall meets another

wall, the floor, or the ceiling. They can also occur where wall finishes are cut to allow the installation of equipment or services.

The following are examples of measures for controlling sound leaks:

• avoid back-to-back electrical outlets or medicine cabinets;

• carefully seal cracks or openings so structures are effectively airtight;

• apply sealant below the plates in stud walls, between the bottom of gypsum board and the structure behind, around all

penetrations for services and, in general, wherever there is a crack, a hole or the possibility of one developing;

• include sound-absorbing material inside the wall if not already required

The reduction of air leakage is also addressed to some extent by the smoke tightness requirements in the Code.

The calculation of and laboratory testing for STC and ASTC ratings are performed on intact assemblies having no penetrations or

doors. When measuring ASTC ratings in the field, openings can be blocked with insulation and drywall.

To verify that the required acoustical performance is being achieved, a field test can be done at an early stage of construction.

ASTM E 336, “Measurement of Airborne Sound Attenuation between Rooms in Buildings,” gives a complete measurement.

A simpler and less expensive method is presented in ASTM E 597, “Determining a Single Number Rating of Airborne Sound

Insulation for Use in Multi-Unit Building Specifications.” The rating derived from this test is usually within 2 points of the STC

obtained from ASTM E 336. It is useful for verifying performance and finding problems during construction. Alterations can

then be made prior to project completion.

airborne

sound

source

direct path

(STC)

flanking

paths

apparent sound transmission class

(ASTC)

EG01380A

separating

floor/ceiling

assembly

flanking

side wall

assemblies

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Impact Noise

Section 9.11. has no requirements for the control of impact noise transmission. However, footsteps and other impacts can cause

severe annoyance in multifamily residences. Builders concerned about quality and reducing occupant complaints will ensure that

floors are designed to minimize impact transmission. A recommended criterion is that bare floors (tested without a carpet) should

achieve an impact insulation class (IIC) of 55. Some lightweight floors that satisfy this requirement may still elicit complaints

about low frequency impact noise transmission. Adding carpet to a floor will always increase the IIC rating but will not necessarily

reduce low frequency noise transmission. Good footstep noise rejection requires fairly heavy floor slabs or floating floors.

The most frequently used test methods for impact noise are ASTM E 492, “Laboratory Measurement of Impact Sound

Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine,” and ASTM E 1007, “Field Measurement of

Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures.”

Machinery Noise

Elevators, garbage chutes, plumbing, fans, and heat pumps are common sources of noise in buildings. To reduce annoyance from

these, they should be placed as far as possible from sensitive areas. Vibrating parts should be isolated from the building structure

using resilient materials such as neoprene or rubber.

A-9.11.1.3.(2)(b) Control of Airborne Noise in Buildings. Tables 9.10.3.1.-A and 9.10.3.1.-B present separating

assemblies that comply with Section 9.11. However, selecting an appropriate separating assembly is only one part of the solution for

reducing airborne sound transmission between adjoining spaces: to fully address the sound performance of the whole system, flanking

assemblies must be connected to the separating assembly in accordance with Article 9.11.1.4.

A-9.11.1.4. Adjoining Constructions. Tables A-9.11.1.4.-A to A-9.11.1.4.-D present generic options for the design and

construction of junctions between separating and flanking assemblies. Constructing according to these options is likely to meet or

exceed an ASTC rating of 47. Other designs may be equally acceptable if their sound resistance can be demonstrated to meet the

minimum ASTC rating or better on the basis of tests referred to in Article 9.11.1.2., or if they comply with Subsection 5.8.1.

However, some caution should be applied when designing solutions that go beyond the options provided in these Tables: for example,

adding more material to a wall could negatively impact its sound performance or have no effect at all.

Table A-9.11.1.4.-A presents compliance options for the construction of separating wall assemblies with flanking floor, ceiling and

wall assemblies in horizontally adjoining spaces.

Table A-9.11.1.4.-A

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Wall Assemblies in

Horizontally Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Wall Assembly with

STC ≥ 50 from

Table 9.10.3.1.-A

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Horizontal Sound Transmission Paths

Bottom Junction (between separating

wall and flanking floors)

Top Junction (between separating wall

and flanking ceiling)

Side Junctions (between separating wall and

flanking walls)

W4, W5, W6

(single stud)

W8, W9, W10,

W11, W12

(staggered studs)

• for additional material layer and

finished flooring, see Table 9.11.1.4.

• subfloor on both sides of wall is

plywood, OSB, waferboard (15.5 mm

thick) or tongue and groove lumber

(≥ 17 mm thick)

• floor is framed with wood joists, wood

I-joists or wood trusses spaced

≥ 400 mm o.c., with or without

absorptive material

(2)

in cavities

• floor joists or trusses are oriented

parallel to separating wall

(non-loadbearing case) or

perpendicular to separating wall but

are not continuous across junction

(loadbearing case)

• ceiling is framed with wood joists,

wood I-joists, or wood trusses, with or

without absorptive material

(2)

in cavities

• ceiling joists or trusses are oriented

perpendicular to separating wall but

are not continuous across junction

(loadbearing case) or parallel to

junction (non-loadbearing case)

• gypsum board ceiling is fastened

directly to bottom of ceiling framing or

on resilient metal channels

(3)

• gypsum board on flanking walls ends or is cut at

separating wall and is fastened directly to

framing or on resilient metal channels

(3)

• flanking wall is framed with single row of wood

studs, staggered studs on a single

38 mm × 140 mm plate, or 2 rows of

38 mm × 89 mm wood studs on separate

38 mm × 89 mm plates, with or without

absorptive material

(2)

in cavities

• flanking wall framing is structurally connected to

separating wall and terminates where it butts

against framing of separating wall or is

continuous across junction

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Example Showing Side View of Bottom and Top Junctions Example Showing Plan View of Side Junctions

Table A-9.11.1.4.-A (continued)

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Wall Assemblies in

Horizontally Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Wall Assembly with

STC ≥ 50 from

Table 9.10.3.1.-A

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Horizontal Sound Transmission Paths

Bottom Junction (between separating

wall and flanking floors)

Top Junction (between separating wall

and flanking ceiling)

Side Junctions (between separating wall and

flanking walls)

EG01399A

ceiling

W5 separating wall

additional material layer

over subfloor plus

finished flooring with

mass per area > 8 kg/m²

EG02084A

W5 separating wall

flanking wall

EG02087A

ceiling

W12 separating wall

additional material

layer over subfloor

plus finished flooring

with mass per area

> 8 kg/m

EG02086A

W12 separating wall

flanking wall

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

W13, W14, W15 • for additional material layer and

finished flooring, see Table 9.11.1.4.

• subfloor on both sides of wall is

plywood, OSB, waferboard (15.5 mm

thick) or tongue and groove lumber

(≥ 17 mm thick)

• floor is framed with wood joists, wood

I-joists or wood trusses spaced

≥ 400 mm o.c., with or without

absorptive material

(2)

in cavities

• floor joists or trusses are oriented

parallel to separating wall

(non-loadbearing case) or

perpendicular to separating wall but

are not continuous across junction

(loadbearing case)

• near leaf of separating wall is

supported on “designated” joist

• wood joists, wood I-joists or wood

trusses are oriented perpendicular or

parallel to separating wall, with or

without absorptive material

(2)

in cavities

• joist framing at junction is supported

on near leaf of separating wall

• gypsum board ceiling panels end at

wall framing and are fastened directly

to bottom of ceiling framing or on

resilient metal channels

(3)

• flanking wall framing is fastened to adjacent leaf

of separating wall

• flanking wall is framed with single row of wood

studs, staggered studs on a single 38 mm ×

140 mm plate, or 2 rows of 38 mm × 89 mm

wood studs on separate 38 mm × 89 mm

plates, with or without absorptive material

(2)

in cavities

• gypsum board panels on flanking walls ends or

is cut at framing of separating wall and is

fastened on resilient metal channels

(3)

directly to framing of flanking wall if that framing

and any sheathing are not continuous across

the junction

Example Showing Side View of Bottom and Top Junctions Example Showing Plan View of Side Junctions

Table A-9.11.1.4.-A (continued)

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Wall Assemblies in

Horizontally Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Wall Assembly with

STC ≥ 50 from

Table 9.10.3.1.-A

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Horizontal Sound Transmission Paths

Bottom Junction (between separating

wall and flanking floors)

Top Junction (between separating wall

and flanking ceiling)

Side Junctions (between separating wall and

flanking walls)

EG01366A

ceiling

W13 separating

wall

additional material

layer over subfloor

plus finished flooring

with mass per area

> 8 kg/m

EG01365A

W13 separating wall

flanking wall

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

S1 to S15 • F1 concrete floor assembly from

Table 9.10.3.1.-B with mass per area

not less than 300 kg/m

(e.g.

normal-weight concrete with average

thickness of 130 mm)

• with or without an additional material

layer or finished flooring

• F1 concrete floor assembly from

Table 9.10.3.1.-B with mass per area

not less than 300 kg/m

(e.g. normal-weight concrete with

average thickness of 130 mm)

• with or without gypsum board ceiling

suspended below concrete floor

• flanking wall framing is structurally connected to

separating wall and terminates where it butts

against framing of separating wall or is

continuous across junction

• gypsum board on flanking walls ends or is cut at

separating wall and is fastened directly to

framing or on resilient metal channels

(3)

• flanking wall consists of steel framing

(loadbearing or non-loadbearing steel studs) or

concrete blocks with mass per area not less

than 200 kg/m

(e.g. normal-weight hollow core

concrete block units

(4)

with a gypsum board

lining supported on framing providing a cavity

not less than 50 mm deep)

• with or without absorptive material

(2)

in cavities

behind gypsum board of flanking walls

Example Showing Side View of Bottom and Top Junctions Example Showing Plan View of Side Junctions

B1 to B10 • same options as stated above for

walls S1 to S15

• same options as stated above for

walls S1 to S15

• junction at top of concrete block

assembly is loadbearing or

non-loadbearing resilient joint

• same options as stated above for walls S1

to S15

Table A-9.11.1.4.-A (continued)

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Wall Assemblies in

Horizontally Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Wall Assembly with

STC ≥ 50 from

Table 9.10.3.1.-A

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Horizontal Sound Transmission Paths

Bottom Junction (between separating

wall and flanking floors)

Top Junction (between separating wall

and flanking ceiling)

Side Junctions (between separating wall and

flanking walls)

EG01368A

concrete floor

S14 separating wall

EG01369A

S14 separating wall

flanking wall

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Table A-9.11.1.4.-B presents options for improving the sound performance of separating wall systems beyond that achieved by

implementing the options presented in Table A-9.11.1.4.-A. The suggested performance improvement options are listed in order of

approximate acoustic priority and are interdependent, i.e., if options at the top of the list are not implemented, then options at the

bottom of the list will have much lesser effect.

Example Showing Side View of Bottom and Top Junctions Examples Showing Plan View of Side Junctions

Notes to Table A-9.11.1.4.-A:

(1) See also Table A-9.11.1.4.-B.

(2) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of

32 kg/m

. See Notes (5) and (8) of Table 9.10.3.1.-A and Note (5) of Table 9.10.3.1.-B for additional information.

(3) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single “leg” between the faces fastened to the

framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, “Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products,”

describes the installation of resilient metal channels.

(4) Normal-weight concrete block units conforming to CSA A165.1, “Concrete Block Masonry Units,” have aggregate with a density not less than 2 000 kg/m

; 190 mm hollow

core units are 53% solid, providing a wall mass per area over 200 kg/m

; 140 mm hollow core units are 75% solid, providing a wall mass per area over 200 kg/m

Table A-9.11.1.4.-A (continued)

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Wall Assemblies in

Horizontally Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Wall Assembly with

STC ≥ 50 from

Table 9.10.3.1.-A

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Horizontal Sound Transmission Paths

Bottom Junction (between separating

wall and flanking floors)

Top Junction (between separating wall

and flanking ceiling)

Side Junctions (between separating wall and

flanking walls)

EG01370A

B3 separating wall

concrete floor

EG01371A

B3 separating wall

flanking wall

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Table A-9.11.1.4.-B

Options for the Construction of a Separating Wall System to Further Improve the

Sound Insulation Performance Achieved with the Options in Table A-9.11.1.4.-A

Type of Separating Wall

Assembly with STC ≥ 50

from Table 9.10.3.1.-A

Performance Improvement Options for Junctions Between Separating Walls and Flanking Floor/Ceiling Assemblies

W4, W5, W6, W8, W9,

W10, W11, W12

• Increase mass per area of additional material layer and finished flooring over subfloor (e.g. concrete or gypsum concrete

topping)

• Choose separating wall assembly with higher STC rating

• Orient floor and ceiling joists parallel to separating wall (non-loadbearing case)

• Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring

• Support gypsum board panels of ceiling on resilient metal channels

(1)

• Support gypsum board panels of flanking walls on resilient metal channels

(1)

W13, W14, W15 • If seismic or other structural requirements permit, choose a fire block detail at floor/wall junction in accordance with

Subsection 9.10.16. that does not provide a rigid connection between the two rows of framing of the separating wall

(e.g. subfloor not continuous across junction and semi-rigid fibre insulation board filling the gap in accordance with

Article 9.10.16.3.). In this case, an additional material layer would not be necessary. Also, choose separating wall assembly

with higher STC rating (e.g. more absorptive material

(2)

in cavities and/or more gypsum board).

• If having a rigid structural connection at the floor/wall junction (such as subfloor continuous across the junction) is required

for seismic or other structural reasons, obtain a higher ASTC rating as follows:

• Increase combined mass per area of additional material layer over subfloor and finished flooring (e.g. concrete or gypsum

concrete topping)

• Choose separating wall assembly with higher STC rating (e.g. more absorptive material

(2)

and/or more gypsum board)

• Support gypsum board panels of ceiling on resilient metal channels

(1)

• Support gypsum board panels of flanking walls on resilient metal channels

(1)

• Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring

S1 to S15 • Choose separating wall assembly with higher STC rating

• Increase thickness of concrete floor slab and/or add material layer and finished flooring over subfloor

• Add gypsum board ceiling on framing supported under the floor above, with cavity not less than 100 mm deep

• Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring

• Support gypsum board panels of flanking walls on resilient metal channels

(1)

if steel studs are loadbearing type

B1 to B10 • Choose separating wall assembly with higher STC rating

• Add gypsum board ceiling supported below concrete floor with cavity not less than 100 mm deep and sound absorptive

material

(2)

in cavity

• Increase thickness of concrete floor slab and/or add material layer and finished flooring over subfloor

• Add resilient layer under additional material layer over subfloor or between additional material layer and finished flooring and

increase mass per area of additional material layer and finished flooring (e.g. floating concrete or gypsum concrete topping)

• Support gypsum board panels of flanking walls on resilient metal channels

(1)

if steel studs are loadbearing type

Notes to Table A-9.11.1.4.-B:

(1) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single “leg” between the faces fastened to the

framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, “Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products,”

describes the installation of resilient metal channels.

(2) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of

32 kg/m

. See Notes (5) and (8) of Table 9.10.3.1.-A and Note (5) of Table 9.10.3.1.-B for additional information.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Table A-9.11.1.4.-C presents compliance options for the construction of separating floor/ceiling assemblies with flanking wall

assemblies in vertically adjoining spaces.

Table A-9.11.1.4.-C

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Floor/Ceiling

Assemblies in Vertically Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Floor/Ceiling Assembly with

STC ≥ 50 from

Table 9.10.3.1.-B

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Vertical Sound Transmission Paths

Junctions with Flanking Steel-Framed Walls Junctions with Flanking Concrete Walls

F1 (with or without gypsum

board ceiling)

• floor ends at flanking wall assembly (T-junction) or extends

beyond it (cross-junction)

• steel framing of flanking walls is loadbearing or

non-loadbearing, with a single row of steel studs, staggered

studs, or 2 rows of studs, with studs spaced not less than

400 mm o.c., with or without absorptive material

(2)

in cavities

• flanking wall structure is fastened to separating concrete

floor but is not continuous across junction

• gypsum board on flanking walls is not continuous across

junction and is fastened directly to wall framing or on

resilient metal channels

(3)

• floor ends at flanking wall assembly (T-junction) or extends

beyond it (cross-junction)

• one wythe of concrete blocks with mass per area not less

than 200 kg/m

(e.g. normal-weight hollow core concrete

block units

(4)

)

• loadbearing (solid) or non-loadbearing (resilient) junction

between top of flanking concrete block wall and floor

structure

• gypsum board lining is supported on wood or steel framing

providing a cavity not less than 50 mm deep, with or without

absorptive material

(2)

in cavities

• gypsum board on flanking walls is not continuous across

junction and is fastened directly to wall framing or on

resilient metal channels

(3)

Examples Showing Side View of Junctions

F8 to F38 Junctions with Flanking Loadbearing or Non-Loadbearing Walls

• wood studs of flanking wall are 38 mm × 89 mm or 38 mm × 140 mm and spaced 400 mm or 600 mm o.c.

• flanking wall framing consists of single row of wood studs, staggered studs on a single 38 mm × 140 mm plate, or 2 rows of

38 mm × 89 mm wood studs on separate 38 mm × 89 mm plates, with or without absorptive material

(2)

in wall cavities

• gypsum board on flanking walls ends or is cut near floor framing and is fastened directly to wall framing or supported on

resilient metal channels

(3)

Example Showing Side View of Junctions in Flanking

Loadbearing Wall

Example Showing Side View of Junctions in Flanking

Non-Loadbearing Wall

EG01372A

S14 wall

F1 separating floor

EG01373A

F1 separating floor

B3 wall

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Table A-9.11.1.4.-D presents options for improving the sound performance of separating floor/ceiling assemblies beyond that

achieved by implementing the options presented in Table A-9.11.1.4.-C. The suggested performance improvement options are listed

in order of approximate acoustic priority and are interdependent, i.e., if options at the top of the list are not implemented, then

options at the bottom of the list will have much lesser effect.

Notes to Table A-9.11.1.4.-C:

(1) See also Table A-9.11.1.4.-D.

(2) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of

32 kg/m

. See Notes (5) and (8) of Table 9.10.3.1.-A and Note (5) of Table 9.10.3.1.-B for additional information.

(3) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single “leg” between the faces fastened to the

framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, “Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products,”

describes the installation of resilient metal channels.

(4) Normal-weight concrete block units conforming to CSA A165.1, “Concrete Block Masonry Units,” have aggregate with a density not less than 2000 kg/m

; 190 mm hollow

core units are 53% solid, providing a wall mass per area over 200 kg/m

; 140 mm hollow core units are 75% solid, providing a wall mass per area over 200 kg/m

Table A-9.11.1.4.-C (continued)

Options for the Design and Construction of Junctions and Flanking Surfaces Between Separating Floor/Ceiling

Assemblies in Vertically Adjoining Spaces for Compliance with Clause 9.11.1.1.(1)(b)

Type of Separating

Floor/Ceiling Assembly with

STC ≥ 50 from

Table 9.10.3.1.-B

Options for Design and Construction of Junctions and Flanking Surfaces

(1)

to Address Vertical Sound Transmission Paths

EG01374A

F8d separating floor

EG01375A

F8d separating floor

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-Table 9.11.1.4. Floor Treatments. The sound insulation performance of lightweight framed floors can be improved by

adding floor treatments, i.e., additional layers of material over the subfloor (e.g. concrete topping, OSB or plywood) and finished

flooring or coverings (e.g., carpet, engineered wood). Table A-Table 9.11.1.4. presents the mass per area values based on thickness and

density of a number of generic floor treatment materials (the values for proprietary products may be different; consult the

manufacturer’s current data sheets for their products’ values).

Table A-9.11.1.4.-D

Options for the Construction of a Separating Floor System to Further Improve the Sound Insulation Performance

Achieved with the Options in Table A-9.11.1.4.C.

Type of Separating Floor

Assembly with STC ≥ 50

from Table 9.10.3.1.-B

Performance Improvement Options for Junctions Between Separating Floors and Flanking Wall Assemblies

F1 (with or without gypsum

board ceiling)

• Add heavier additional material layer over subfloor and/or resilient layer under additional material layer or between additional

material layer and finished flooring

• Add gypsum board ceiling supported at least 100 mm below concrete floor with minimal structural connection (e.g. ceiling

framing supported resiliently) and sound absorptive material

(1)

in cavity

• Support gypsum board of flanking walls of lower room on resilient metal channels

(2)

(if framed with loadbearing studs)

F8 to F38 • Add heavier additional material layer over subfloor and/or resilient layer under additional material layer or between additional

material layer and finished flooring

• Add more/heavier gypsum board to ceiling and increase spacing of resilient metal channels

(2)

to 600 mm o.c.

• Support gypsum board of flanking loadbearing walls of lower room on resilient metal channels

(2)

• Support gypsum board on flanking non-loadbearing walls of lower room on resilient metal channels

(2)

Notes to Table A-9.11.1.4.-D:

(1) Sound absorptive material is porous (closed-cell foam was not tested) and includes fibre processed from rock, slag, glass or cellulose fibre with a maximum density of

32 kg/m

. See Notes (5) and (8) of Table 9.10.3.1.-A and Note (5) of Table 9.10.3.1.-B for additional information.

(2) Resilient metal channels are formed from steel having a maximum thickness of 0.46 mm (25 gauge) with slits or holes in the single “leg” between the faces fastened to the

framing and to the gypsum board (see Figure A-9.10.3.1.-D). ASTM C 754, “Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products,”

describes the installation of resilient metal channels.

Table A-9.11.1.4.

Mass per Area of Floor Treatment Materials

Floor Treatment Material Thickness, mm Density, kg/m³ Mass per Area, kg/m

Materials Typically Having a Mass per Area Less Than 8 kg/m

Medium-density fibreboard (MDF) 2.9–6.1 790-–810 2.3–5.0

Plywood – generic softwood 12.5–13.3 450–500 5.6–6.6

15.5–16.3 7.0–8.1

Ceramic tile 8.4 700–1 000 5.9–8.4

Materials Typically Having a Mass per Area Greater Than 8 kg/m

but Less Than 16 kg/m

Particleboard 11.3–19.2 710–755 8.1–14.5

Medium-density fibreboard (MDF) 13.9–21.1 640–755 8.9–15.9

Oriented strandboard (OSB) 14.3–15.8 600–680 8.6–10.7

17.3–18.8 10.4–12.8

Plywood – generic softwood 25.5 450–500 11.5–13.1

Materials Typically Having a Mass per Area Greater Than 16 kg/m² but Less Than 32 kg/m

Medium-density fibreboard (MDF) 25.0–32.1 640–740 16.0–23.7

Materials Typically Having a Mass per Area Greater Than 32 kg/m

Concrete 40.0–50.0 2 015–2 380 80.6–119.0

Gypsum concrete 25.0 1 840–1 870 46.1–46.7

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-Table 9.12.2.2. Minimum Depths of Foundations. The requirements for clay soils or soils not clearly defined are

intended to apply to those soils that are subject to significant volume changes with changes in moisture content.

A-9.12.2.2.(2) Depth and Insulation of Foundations.

Figure A-9.12.2.2.(2)

Foundation insulation and heat flow to footings

A-9.12.3.3.(1) Deleterious Material in Backfill. The deleterious debris referred to in this provision includes, but is not

limited to:

• organic material and other material subject to decomposition and compaction, which could have an adverse effect on grading

around the building,

• materials that will off-gas and have the potential to pose a health hazard, and

• materials that are incompatible with materials used in the foundations, footings, drainage materials or components, or other

elements of the building whose required performance would be adversely affected.

A-9.13.2.5. Protection of Interior Finishes against Moisture. Excess water from cast-in-place concrete and ground

moisture tends to migrate toward interior spaces, particularly in the spring and summer. Where moisture-susceptible materials, such as

finishes or wood members, are in contact with the foundation wall, the moisture needs to be controlled by installing a moisture barrier

on the interior surface of the foundation wall that extends from the underside of the interior finish up the face of the wall to a point

just above the level of the ground outside.

EC00381A

heat flow

Insulated in a manner that will reduce

heat flow to the soil beneath the footings

(b)

heat flow

Insulated in a manner allowing heat flow

to the soil beneath the footings

(a)

heat flow

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

The reason the moisture barrier on the interior surface of the foundation wall must be stopped near ground level is to allow any

moisture that finds its way into the finished wall cavity from the interior space (through leaks in the air or vapour barrier) to diffuse to

the exterior. If the vapour permeance of dampproofing membranes or coatings exceeds 170 ng/(Pa·s·m

), such moisture barriers may

be carried full height; if their vapour permeance is less than that, this moisture risks being trapped on the interior surface of the

moisture barriers. The permeance limit corresponds to the lower limit for breather-type membranes, such as asphalt-impregnated

sheathing paper.

Some insulation products can also be used to protect interior finishes from the effects of moisture. They have shown acceptable

performance when applied over the entire foundation wall because, in this case, they also provide vapour barrier and moisture barrier

functions and possibly also the air barrier function. Where a single product provides all these functions, there is no risk of trapping

moisture between two functional barriers with low water vapour permeance.

A-9.13.4. Soil Gas Control. Outdoor air entering a dwelling through above-grade leaks in the building envelope normally

improves the indoor air quality in the dwelling by reducing the concentrations of pollutants and water vapour. It is only undesirable

because it cannot be controlled. On the other hand, air entering a dwelling through below-grade leaks in the envelope may increase the

water vapour content of the indoor air and may also bring in a number of pollutants picked up from the soil. This mixture of air, water

vapour and pollutants is sometimes referred to as “soil gas.” One pollutant often found in soil gas is radon.

Sentence 9.13.4.2.(1), which requires the installation of an air barrier system, addresses the protection from all soil gases, while the

remainder of Article 9.13.4.2. along with Article 9.13.4.3., which require the provision of the means to depressurize the space between

the air barrier system and the ground, specifically address the capability to mitigate high radon concentrations in the future, should

this become necessary.

Radon is a colourless, odourless, radioactive gas that occurs naturally as a result of the decay of radium. It is found to varying degrees as

a component of soil gas in all regions of Canada and is known to enter dwelling units by infiltration into basements and crawl spaces.

The presence of radon in sufficient quantity can lead to an increased risk of lung cancer.

The potential for high levels of radon infiltration is very difficult to evaluate prior to construction and thus a radon problem may only

become apparent once the building is completed and occupied. Therefore various sections of Part 9 require the application of certain

radon exclusion measures in all dwellings. These measures are

• low in cost,

• difficult to retrofit, and

• desirable for other benefits they provide.

The principal method of resisting the ingress of all soil gases, a resistance which is required for all buildings (see Sentence 9.13.4.2.(1)),

is to seal the interface between the soil and the occupied space, so far as is reasonably practicable. Sections 9.18. and 9.25. contain

requirements for air and soil gas barriers in assemblies in contact with ground, including those in crawl spaces. Providing control joints

to reduce cracking of foundation walls and airtight covers for sump pits (see Section 9.14.) are other measures that can help achieve

this objective. The requirements provided in Subsection 9.25.3. are explained in Notes A-9.25.3.4. and 9.25.3.6. and A-9.25.3.6.(2)

and (3).

The principal method of excluding radon is to ensure that the pressure difference across the ground/space interface is positive

(i.e., towards the outside) so that the inward flow of radon through any remaining leaks will be minimized. The requirements provided

in Article 9.13.4.3. are explained in Note A-9.13.4.3.

A-9.13.4.2.(3) Exception for Buildings Occupied for a Few Hours a Day. The criterion used by Health Canada to

establish the guideline for acceptable radon concentration is the time that occupants spend inside buildings. Health Canada

recommends installing a means for the future removal of radon in b

uildings that are occupied by persons for more than 4 hours

per day. Sentence 9.13.4.2.(3) therefore does not apply to buildings or portions of buildings that are intended to be occupied for less

than 4 hours a day. Addressing a radon problem in such buildings in the future, should that become necessary, can also be achieved by

providing a means for increased ventilation at times when these buildings are occupied.

A-9.13.4.3.

Providing Performance Criteria for the Depressurization of the Space Between the Air Barrier System and

the Ground

Article 9.13.4.3. contains two sets of requirements: Sentence (2) describes the criteria for subfloor depressurization systems using

performance-oriented language, while Sentence (3) describes one particular acceptable solution using more prescriptive language.

In some cases, subfloor depressurization requires a solution other than the one described in Sentence (3), for example, where

compactable fill is installed under slab-on-grade construction.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Completion of a Subfloor Depressurization System

The completion of a subfloor depressurization system may be necessary to reduce the radon concentration to a level below the

guideline specified by Health Canada. In this case, to complete the system, the radon vent pipe is mechanically assisted to enable

effective depressurization of the space between the air barrier system and the ground. An electrically powered fan is typically

installed somewhere along the radon vent pipe.

Further information on protection from radon ingress can be found in the following Health Canada publications:

• “Radon: A Guide for Canadian Homeowners” (CMHC/HC), and

• “Guide for Radon Measurements in Residential Dwellings (Homes).”

A-9.13.4.3. Vent Terminals. To prevent soil gases from entering a building through air intakes, windows, and other openings

in the building envelope, radon vent pipe terminations should be installed in a similar manner to plumbing vent terminals.

(See A-2.5.6.5.(4) in Appendix A of Division B to Book II of the Code.)

A-9.13.4.3.(2)(b)(i) and (3)(b)(i) Effective Depressurization. To allow effective depressurization of the space between

the air barrier system and the ground, the extraction opening (the pipe) should not be blocked and should be arranged such that air

can be extracted from the entire space between the air barrier system and the ground. This will ensure that the extraction system can

maintain negative pressure underneath the entire floor (or in heated crawl spaces underneath the air barrier system). The arrangement

and location of the extraction system inlet(s) may have design implications where the footing layout separates part of the space

underneath the floor.

A-9.14.2.1.(2)(a) Insulation Applied to the Exterior of Foundation Walls. In addition to the prevention of heat loss,

some types of mineral fibre insulation, such as rigid glass fibre, are installed on the exterior of basement walls for the purpose of

moisture control. This is sometimes used instead of crushed rock as a drainage layer between the basement wall and the surrounding

soil in order to facilitate the drainage of soil moisture. Water drained by this drainage layer must be carried away from the foundation

by the footing drains or the granular drainage layer in order to prevent it from developing hydro-static pressure against the wall.

Provision must be made to permit the drainage of this water either by extending the insulation or crushed rock to the drain or by the

installation of granular material connecting the two. The installation of such drainage layer does not eliminate the need for normal

waterproofing or dampproofing of walls as specified in Section 9.13.

A-9.15.1.1. Application of Footing and Foundation Requirements to Decks and Similar

Constructions. Because decks, balconies, verandas and similar platforms support occupancies, they are, by definition, considered

as buildings or parts of buildings. Consequently, the requirements in Section 9.15. regarding footings and foundations apply to these

constructions.

A-9.15.1.1.(1)(c) and 9.20.1.1.(1)(b) Flat Insulating Concrete Form Walls. Insulating concrete form (ICF) walls are

concrete walls that are cast into polystyrene forms, which remain in place after the concrete has cured. Flat ICF walls are solid ICF

walls where the concrete is of uniform thickness over the height and width of the wall.

A-9.15.2.4.(1) Preserved Wood Foundations – Design Assumptions. Tabular data and figures in CSA S406,

“Permanent Wood Foundations for Housing and Small Buildings,” are based upon the general principles provided in CSA O86,

“Engineering Design in Wood,” with the following assumptions:

•

soil bearing capacity: 75 kPa or more,

• clear spans for floors: 5 000 mm or less,

• floor loadings: 1.9 kPa for first floor and suspended floor, and 1.4 kPa for second storey floor,

• foundation wall heights: 2 400 mm for slab floor, 3 000 mm for suspended wood floor,

• top of granular layer to top of suspended wood floor: 600 mm,

• lateral load from soil pressure: equivalent to fluid pressure of 4.7 kPa per metre of depth,

• ground snow load: 3 kPa,

• basic snow load coefficient: 0.6,

• roof loads are carried to the exterior wall,

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

•dead loads:

A-9.15.3.4.(2) Footing Sizes. The footing sizes in Table 9.15.3.4. are based on typical construction consisting of a roof,

not more than 3 storeys, and centre bearing walls or beams. For this reason, Clause 9.15.3.3.(1)(b) stipulates a maximum supported

joist span of 4.9 m.

It has become common to use flat wood trusses or wood I-joists to span greater distances in floors of small buildings. Where these

spans exceed 4.9 m, minimum footing sizes may be based on the following method:

(a) Determine for each storey the span of joists that will be supported on a given footing. Sum these lengths (sum

(b) Determine the product of the number of storeys times 4.9 m (sum

to sum

(d) Multiply this ratio by the minimum footing sizes in Table 9.15.3.4. to get the required minimum footing size.

Example: A 2-storey house is built using wood I-joists spanning 6 m.

(a) sum

= 6 + 6 = 12 m

(b) sum

= 4.9 × 2 = 9.8 m

/sum

= 12/9.8 = 1.22

(d) required minimum footing size = 1.22 × 350 mm (minimum footing size provided in Table 9.15.3.4.) = 427 mm.

A-9.16.2.1.(1) Drainage Layer Beneath Floors-on-Ground. A drainage layer required by Sentence 9.16.2.1.(1) shall also

be gas-permeable and conform to Article 9.13.4.3. in buildings to which that Article applies.

A-9.17.2.2.(2) Lateral Support of Columns. Because the Code does not provide prescriptive criteria to describe the

minimum required lateral support, constructions are limited to those that have demonstrated effective performance over time and

those that are designed according to Part 4. Verandas on early 20th century homes provide one example of constructions whose floor

and roof are typically tied to the rest of the building to provide effective lateral support. Large decks set on tall columns, however,

are likely to require additional lateral support even where they are connected to the building on one side.

A-9.17.3.4. Design of Steel Columns. The permitted live floor loads of 2.4 kPa and the spans described for steel beams,

wood beams and floor joists are such that the load on columns could exceed 36 kN, the maximum allowable load on columns

prescribed in CAN/CGSB-7.2, “Adjustable Steel Columns.” In the context of Part 9, loads on columns are calculated from the

supported area times the live load per unit area, using the supported length of joists and beams. The supported length is half of the

joist spans on each side of the beam and half the beam span on each side of the column.

Dead load is not included based on the assumption that the maximum live load will not be applied over the whole floor. Designs

according to Part 4 must consider all applied loads.

A-9.18.7.1.(4) Protection of Ground Cover in Warm Air Plenums. The purpose of the requirement is to protect

combustible ground cover from smouldering cigarette butts that may drop through air registers. The protective material should extend

beyond the opening of the register and have up-turned edges, as a butt may be deflected sideways as it falls.

A-9.19.1.1.(1) Venting of Attic or Roof Spaces. Controlling the flow of moisture by air leakage and vapour diffusion into

attic or roof spaces is necessary to limit moisture-induced deterioration. Given that imperfections normally exist in the vapour barriers

and air barrier systems, recent research indicates that venting of attic or roof spaces is generally still required. The exception provided

in Article 9.19.1.1. recognizes that some specialized ceiling-roof assemblies, such as those used in some factory-built buildings, have,

over time, demonstrated that their construction is sufficiently tight to prevent excessive moisture accumulation. In these cases,

ventilation would not be required.

roof 0.50 kPa

floor 0.47 kPa

wall (with siding) 0.32 kPa

wall (with masonry veneer) 1.94 kPa

foundation wall 0.27 kPa

partitions 0.20 kPa

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.19.2.1.(1) Access to Attic or Roof Space. The term “open space” refers to the space between the insulation and the

roof sheathing. Sentence 9.19.2.1.(1) requires the installation of an access hatch where the open space in the attic or roof is large

enough to allow visual inspection. Although the dimensions of an uninsulated attic or roof space may meet the size that triggers the

requirement for an access hatch to be installed, most of that space will actually be filled with insulation and may therefore not be easily

inspected, particularly in smaller buildings or under low-sloped roofs. See also Article 9.36.2.6.

A-9.20.1.2. Seismic Information. Information on spectral response acceleration values for various locations can be found in

Appendix C.

A-9.20.5.1.(1) Masonry Support. Masonry veneer must be supported on a stable structure in order to avoid cracking of the

masonry due to differential movement relative to parts of the support. Wood framing is not normally used as a support for the weight

of masonry veneer because of its shrinkage characteristics. Where the weight of masonry veneer is supported on a wood structure, as is

the case for the preserved wood foundations referred to in Sentence 9.20.5.1.(1) for example, measures must be taken to ensure that

any differential movement that may be harmful to the performance of masonry is minimized or accommodated. The general principle

stated in Article 9.4.1.1., however, makes it possible to support the weight of masonry veneer on wood framing, provided that

engineering design principles prescribed in Part 4 are followed to ensure that the rigidity of the support is compatible with the stiffness

of the masonry being supported and that differential movements between the support and masonry are accommodated.

A-9.20.8.5.(1) Projection of Masonry Beyond Supporting Members.

Figure A-9.20.8.5.(1)

Maximum projection of masonry veneer beyond its support

EG00573E

solid

masonry

units

projection of masonry

veneer ≤ 1/3 of its thickness

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.20.12.2.(2) Corbelling of Masonry Foundation Walls.

Figure A-9.20.12.2.(2)

Maximum corbel dimensions

A-9.20.13.9.(3) Dampproofing of Masonry Walls. The reason for installing a sheathing membrane behind masonry walls

is to prevent rainwater from reaching the interior finish if it should leak past the masonry. The sheathing membrane intercepts the

rainwater and leads it to the bottom of the wall where the flashing directs it to the exterior via weep holes. If the insulation is a type

that effectively resists the penetration of water, and is installed so that water will not collect behind it, then there is no need for a

sheathing membrane. If water that runs down between the masonry and the insulation is able to leak out at the joints in the insulation,

such insulation will not act as a substitute for a sheathing membrane. If water cannot leak through the joints in the insulation but

collects in cavities between the masonry and insulation, subsequent freezing could damage the wall. Where a sheathing membrane is

not used, the adhesive or mortar should therefore be applied to form a continuous bond between the masonry and the insulation.

If this is not practicable because of an irregular masonry surface, then a sheathing membrane is necessary.

A-9.21.3.6.(2) Metal Chimney Liners. Under the provisions of Article 1.2.1.1. of Division A, masonry chimneys with metal

liners may be permitted to serve solid-fuel-burning appliances if tests show that such liners will provide an equivalent level of safety.

inner face of

cavity wall

EG00450B

brick

≤ h/2 and ≤ t

brick

≤ t

foundation

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.21.4.4.(1) Location of Chimney Top.

Figure A-9.21.4.4.(1)

Vertical and horizontal distances from chimney top to roof

A-9.21.4.5.(2) Lateral Support for Chimneys. Where a chimney is fastened to the house framing with metal anchors,

in accordance with CSA A370, “Connectors for Masonry,” it is considered to have adequate lateral support. The portion of the

chimney stack above the roof is considered as free standing and may require additional lateral support.

A-9.21.5.1.(1) Clearance from Combustible Materials. For purposes of this Sentence, an exterior chimney can be

considered to be one which has at least one surface exposed to the outside atmosphere or unheated space over the majority of its

height. All other chimneys should be considered to be interior.

A-9.23.1.1. Constructions Other than Light Wood-Frame Constructions. The prescriptive requirements in

Section 9.23. apply only to standard light wood-frame construction. Other constructions, such as post, beam and plank construction,

plank frame wall construction, and log construction must be designed in accordance with Part 4.

A-9.23.1.1.(1) Application of Section 9.23. In previous editions of the Code, Sentence 9.23.1.1.(1) referred to

“conventional” wood-frame construction. Over time, conventions have changed and the application of Part 9 has expanded.

The prescriptive requirements provided in Section 9.23. still focus on lumber beams, joists, studs and rafters as the main structural

elements of “wood-frame construction.” The requirements recognize – and have recognized for some time – that walls and floors may

be supported by components made of material other than lumber; for example, by foundations described in Section 9.15. or by steel

beams described in Article 9.23.4.3. These constructions still fall within the general category of wood-frame construction.

With more recent innovations, alternative structural components are being incorporated into wood-frame buildings. Wood I-joists,

for example, are very common. Where these components are used in lieu of lumber, the requirements in Section 9.23. that specifically

apply to lumber joists do not apply to these components: for example, limits on spans and acceptable locations for notches and holes.

However, requirements regarding the fastening of floor sheathing to floor joists still apply, and the use of wood I-joists does not affect

the requirements for wall or roof framing.

Similarly, if steel floor joists are used in lieu of lumber joists, the requirements regarding wall or roof framing are not affected.

Conversely, Sentence 9.23.1.1.(1) precludes the installation of precast concrete floors on wood-frame walls since these are not

“generally comprised of … small repetitive structural members … spaced not more than 600 mm o.c.”

900 mm min.

600 mm min.

less than 3 m

600 mm min.

3 m

EG00457B

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Thus, the reference to “engineered components” in Sentence 9.23.1.1.(1) is intended to indicate that, where an engineered product is

used in lieu of lumber for one part of the building, this does not preclude the application of the remainder of Section 9.23. to the

structure, provided the limits to application with respect to cladding, sheathing or bracing, spacing of framing members, supported

loads and maximum spans are respected.

A-9.23.3.1.(2) Alternative Nail Sizes. Where power nails or nails with smaller diameters than that required by

Table 9.23.3.4. are used to connect framing, the following equations can be used to determine the required spacing or required

number of nails.

The maximum spacing can be reduced using the following equation:

where

adj = adjusted nail spacing ≥ 20 × nail diameter,

table = nail spacing required by Table 9.23.3.4.,

red = smaller nail diameter than that required by Table 9.23.3.1., and

table = nail diameter required by Table 9.23.3.1.

The number of nails can be increased using the following equation:

where

adj = adjusted number of nails,

table = number of nails required by Table 9.23.3.4.,

table = nail diameter required by Table 9.23.3.1., and

red = smaller nail diameter than required by Table 9.23.3.1.

Note that nails should be spaced sufficiently far apart – preferably no less than 55 mm apart – to avoid splitting of framing lumber.

A-9.23.3.1.(3) Standard for Screws. The requirement that wood screws conform to ASME B18.6.1, “Wood Screws

(Inch Series),” is not intended to preclude the use of Robertson head screws. The requirement is intended to specify the mechanical

properties of the fastener, not to restrict the means of driving the fastener.

A-9.23.3.3.(1) Prevention of Splitting. Figure A-9.23.3.3.(1) illustrates the intent of the phrase “staggering the nails in the

direction of the grain.”

Figure A-9.23.3.3.(1)

Staggered nailing

A-Table 9.23.3.5.-B Alternative Nail Sizes. Where power nails or nails having a different diameter than the diameters listed

in CSA B111, “Wire Nails, Spikes and Staples,” are used to connect the edges of the wall sheathing to the wall framing of

wood-sheathed braced wall panels, the maximum spacing should be as shown in Table A-Table 9.23.3.5.-B.

direction of grain

staggered nailing

EG01218A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.23.4.2. Span Tables for Wood Joists, Rafters and Beams. In these span tables the term “rafter” refers to a sloping

wood framing member which supports the roof sheathing and encloses an attic space but does not support a ceiling. The term “roof

joist” refers to a horizontal or sloping wood framing member that supports the roof sheathing and the ceiling finish but does not

enclose an attic space.

Where rafters or roof joists are intended for use in a locality having a higher specified roof snow load than shown in the tables,

the maximum member spacing may be calculated as the product of the member spacing and specified snow load shown in the span

tables divided by the specified snow load for the locality being considered. The following examples show how this principle can be

applied:

(a) For a 3.5 kPa specified snow load, use spans for 2.5 kPa and 600 mm o.c. spacing but space members 400 mm o.c.

(b) For a 4.0 kPa specified snow load, use spans for 2.0 kPa and 600 mm o.c. spacing but space members 300 mm o.c.

The maximum spans in the span tables are measured from the inside face or edge of support to the inside face or edge of support.

In the case of sloping roof framing members, the spans are expressed in terms of the horizontal distance between supports rather than

the length of the sloping member. The snow loads are also expressed in terms of the horizontal projection of the sloping roof. Spans for

odd size lumber may be estimated by straight line interpolation in the tables.

These span tables may be used where members support a uniform live load only. Where the members are required to be designed to

support a concentrated load, they must be designed in conformance with Subsection 4.3.1.

Supported joist length in Span Tables 9.23.4.2.-H, 9.23.4.2.-I and 9.23.4.2.-J means half the sum of the joist spans on both sides of

the beam. For supported joist lengths between those shown in the tables, straight line interpolation may be used in determining the

maximum beam span.

Span Tables 9.23.4.2.-A to 9.23.12.3.-D cover only the most common configurations. Especially in the area of floors, a wide variety of

other configurations is possible: glued subfloors, concrete toppings, machine stress rated lumber, etc. The Canadian Wood Council

publishes “The Span Book,” a compilation of span tables covering many of these alternative configurations. Although these tables have

not been subject to the formal committee review process, the Canadian Wood Council generates, for the CCBFC, all of the Code’s

span tables for wood structural components; thus Code users can be confident that the alternative span tables in “The Span Book”

are consistent with the span tables in the Code and with relevant Code requirements.

Spans for wood joists, rafters and beams which fall outside the scope of these tables, including those for U.S. species and individual

species not marketed in the commercial species combinations described in the span tables, can be calculated in conformance with

CSA O86, “Engineering Design in Wood.”

A-9.23.4.2.(2) Numerical Method to Establish Vibration-Controlled Spans for Wood-Frame Floors.

In addition to the normal strength and deflection analyses, the calculations on which the floor joist span tables are based include a

method of ensuring that the spans are not so long that floor vibrations could lead to occupants perceiving the floors as too “bouncy” or

“springy.” Limiting deflection under the normal uniformly distributed loads to 1/360 of the span does not provide this assurance.

Normally, vibration analysis requires detailed dynamic modelling. However, the calculations for the span tables use the following

simplified static analysis method of estimating vibration-acceptable spans:

• The span which will result in a 2 mm deflection of a single joist

supporting a 1 kN concentrated midpoint load is calculated.

• This span is multiplied by a factor, K, to determine the “vibration-controlled” span for the entire floor system. If this span is less

than the strength- or deflection-controlled span under uniformly distributed load, the vibration-controlled span becomes the

maximum span.

Table A-Table 9.23.3.5.-B

Alternative Nail Diameters and Spacing

Element Nail Diameter, mm

(1)

Maximum Spacing of Nails Along Edges of

Wall Sheathing, mm o.c.

Plywood, OSB or waferboard 2.19-2.52 75

2.53-2.82 100

2.83-3.09 125

> 3.09 150

Notes to Table A-Table 9.23.3.5.-B:

(1) For alternative nail lengths of 63 mm or longer.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

• The K factor is determined from the following relationship:

where

A, B = constants, the values of which are determined from Tables A-9.23.4.2.(2)-A or A-9.23.4.2.(2)-B,

G = constant, the value of which is determined from Table A-9.23.4.2.(2)-C,

i = span which results in a 2 mm deflection of the joist in question under a 1 kN concentrated midpoint load,

184 = span which results in a 2 mm deflection of a 38 × 184 mm joist of same species and grade as the joist in question

under a 1 kN concentrated midpoint load.

For a given joist species and grade, the value of K shall not be greater than K

, the value which results in a vibration-controlled span of

exactly 3 m. This means that for vibration-controlled spans 3 m or less, K always equals K

, and for vibration-controlled spans greater

than 3 m, K is as calculated.

Note that, for a sawn lumber joist, the ratio S

184

is equivalent to its depth (mm) divided by 184.

Due to rounding differences, the method, as presented here, might produce results slightly different from those produced by the

computer program used to generate the span tables.

Table A-9.23.4.2.(2)-A

Constants A and B for Calculating Vibration-Controlled Floor Joist Spans – General Cases

Forming Part of Note A-9.23.4.2.(2)

Subfloor

Thickness, mm

With Strapping

(1)

With Bridging With Strapping and Bridging

Joist Spacing, mm Joist Spacing, mm Joist Spacing, mm

300 400 600 300 400 600 300 400 600

Constant A

15.5 0.30 0.25 0.20 0.37 0.31 0.25 0.42 0.35 0.28

19.0 0.36 0.30 0.24 0.45 0.37 0.30 0.50 0.42 0.33

Constant B

0.33 0.38 0.41

Notes to Table A-9.23.4.2.(2)-A:

(1) Gypsum board attached directly to joists can be considered equivalent to strapping.

Table A-9.23.4.2.(2)-B

Constants A and B for Calculating Vibration-Controlled Floor Joist Spans – Special Cases

Forming Part of Note A-9.23.4.2.(2)

Subfloor

Thickness, mm

Joists with Ceiling Attached to Wood Furring

(1)

Joists with Concrete Topping

(2)

Without Bridging With Bridging With or Without Bridging

Joist Spacing, mm Joist Spacing, mm Joist Spacing, mm

300 400 600 300 400 600 300 400 600

Constant A

15.5 0.39 0.33 0.24 0.49 0.44 0.38 0.58 0.51 0.41

19.0 0.42 0.36 0.27 0.51 0.46 0.40 0.62 0.56 0.47

Constant B

0.34 0.37 0.35

Notes to Table A-9.23.4.2.(2)-B:

(1) Wood furring means 19 × 89 mm boards not more than 600

mm o.c., or 19 × 64 mm boards not more than 300 mm o.c. For all other cases, see Table A-9.23.4.2.(2)-A.

(2) 30 mm to 51 mm normal weight concrete (not less than 20 MPa) placed directly on the subflooring.

ln (K) ⫽ A – B•ln(S

184

) ⫹ G

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Additional background information on this method can be found in the following publications:

• Onysko, D.M. “Deflection Serviceability Criteria for Residential Floors.” Project 43-10C-024. Forintek Canada Corp., Ottawa,

Canada 1988.

• Onysko, D.M. “Performance and Acceptability of Wood Floors – Forintek Studies.” Proceedings of Symposium/Workshop on

Serviceability of Buildings, Ottawa, May 16-18, National Research Council of Canada, Ottawa, 1988.

A-9.23.4.3.(1) Maximum Spans for Steel Beams Supporting Floors in Dwellings. A beam may be considered to be

laterally supported if wood joists bear on its top flange at intervals of 600 mm or less over its entire length, if all the load being applied

to this beam is transmitted through the joists and if 19 mm by 38 mm wood strips in contact with the top flange are nailed on both

sides of the beam to the bottom of the joists supported. Other additional methods of positive lateral support are acceptable.

For supported joist lengths intermediate between those in the table, straight line interpolation may be used in determining the

maximum beam span.

A-Table 9.23.4.3. Spans for Steel Beams. The spans provided in Table 9.23.4.3. reflect a balance of engineering and

acceptable proven performance. The spans have been calculated based on the following assumptions:

• simply supported beam spans

• laterally supported top flange

• yield strength 350 MPa

• deflection limit L/360

• live load: first floor = 1.9 kPa; second floor = 1.4 kPa

• dead load: 1.5 kPa (0.5 kPa floor + 1.0 kPa partition)

The calculation used to establish the specified maximum beam spans also applies a revised live load reduction factor to account for the

lower probability of a full live load being applied over the supported area in Part 9 buildings.

A-9.23.4.4. Concrete Topping. Vibration-controlled spans given in Span Table 9.23.4.2.-B for concrete topping are based on

a partial composite action between the concrete, subflooring and joists. Normal weight concrete having a compressive strength of

not less than 20 MPa, placed directly on the subflooring, provides extra stiffness and results in increased capacity. The use of a bond

breaker between the topping and the subflooring, or the use of lightweight concrete topping limits the composite effects.

Where either a bond breaker or lightweight topping is used, Span Table 9.23.4.2.-A may be used but the additional dead load imposed

by the concrete must be considered. The addition of 51 mm of concrete topping can impose an added load of 0.8 to 1.2 kPa,

depending on the density of the concrete.

Table A-9.23.4.2.(2)-C

Constant G for Calculating Vibration-Controlled Floor Joist Spans

Forming Part of Note A-9.23.4.2.(2)

Floor Description Constant G

Floors with nailed

(1)

subfloor 0.00

Floor with nailed and field-glued

(2)

subfloor, vibration-controlled span greater than 3 m 0.10

Floor with nailed and field-glued

(2)

subfloor, vibration-controlled span 3 m or less 0.15

Notes to Table A-9.23.4.2.(2)-C:

(1) Common wire nails, spiral nails or wood screws can be considered equivalent for this purpose.

(2) Subfloor field-glued to floor joists with elastomeric adhesive complying with CAN/CGSB-71.26-M, “Adhesive for Field-Gluing Plywood to Lumber Framing for

Floor Systems.”

Example

Assumptions:

– basic dead load = 0.5 kPa

– topping dead load = 0.8 kPa

– total dead load = 1.3 kPa

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

The spacing of joists in the span tables can be conservatively adjusted to allow for the increased load by using the spans in Span

Table 9.23.4.2.-A for 600 mm spacing, but spacing the joists 400 mm apart. Similarly, floor beam span tables can be adjusted by using

4.8 m supported length spans for cases where the supported length equals 3.6 m.

A-9.23.8.3. Joint Location in Built-Up Beams.

Figure A-9.23.8.3.

Joint location in built-up beams

A-9.23.10.4.(1) Fingerjoined Lumber. NLGA 2014, “Standard Grading Rules for Canadian Lumber,” referenced in

Article 9.3.2.1., refers to two special product standards, SPS-1, “Fingerjoined Structural Lumber,” and SPS-3, “Fingerjoined “Vertical

Stud Use Only” Lumber,” produced by NLGA. Material identified as conforming to these standards is considered to meet the

requirements in this Sentence for joining with a structural adhesive. Lumber fingerjoined in accordance with SPS-3 should be used as

a vertical end-loaded member in compression only, where sustained bending or tension-loading conditions are not present, and where

the moisture content of the wood will not exceed 19%. Fingerjoined lumber may not be visually regraded or remanufactured into a

higher stress grade even if the quality of the lumber containing fingerjoints would otherwise warrant such regrading.

– live load = 1.9 kPa

– vibration limit per Note A-9.23.4.2.(2)

– deflection limit = 1/360

– ceiling attached directly to joists, no bridging

not more than

one joint per piece

in each span

no joints permitted

in the end spans

in this location

column

bearing plate

above column

joints in not more

than half the members

at these locations

( 150 mm)

–

( 150 mm)

EG00908B

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.23.10.6.(3) Single Studs at Sides of Openings.

Figure A-9.23.10.6.(3)-A

Single studs at openings in non-loadbearing interior walls

Figure A-9.23.10.6.(3)-B

Single studs at openings in all other walls

(a)

Configurations which comply

(a) full height studs both sides

(b) full height studs both sides and opening within stud space

Configurations which do not comply

(a) opening wider than stud space without full height studs

both sides

(b) opening narrower than but not within stud space

(a) (b) (c)

(b)

EC00296B

Configurations which comply

(a), (b), (c) openings all narrower than and within stud space;

no two full stud space width openings in adjacent

stud spaces

Configurations which do not comply

(a) opening wider than stud space

(b) opening narrower than but not within stud space

(a) (b) (c)

EC00296C

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.23.13. Bracing for Resistance to Lateral Loads. Subsection 9.23.14. along with

Articles 9.23.3.4., 9.23.3.5., 9.23.6.1., 9.23.9.8., 9.23.15.5., 9.29.5.8., 9.29.5.9., 9.29.6.3. and 9.29.9.3. provide explicit

requirements to address resistance to wind and earthquake loads in higher wind and earthquake regions of British Columbia.

A-9.23.13.1.

Bracing to Resist Lateral Loads in Low Load Locations

Of the 109

locations identified in Appendix C, 68 are locations where the seismic spectral response acceleration, S

(0.2), is less than or

equal to 0.70 and the 1-in-50 hourly wind pressure is less than 0.80 kPa. For buildings in these locations, Sentence 9.23.13.1.(2)

requires only that exterior walls be braced using the acceptable materials and fastening specified. There are no spacing or dimension

requirements for braced wall panels in these buildings.

Structural Design for Lateral Wind and Earthquake Loads

In cases where lateral load design is required, CWC 2014, “Engineering Guide for Wood Frame Construction,” provides acceptable

engineering solutions as an alternative to Part 4. The CWC Guide also contains alternative solutions and provides information on the

applicability of the Part 9 prescriptive structural requirements to further assist designers and building officials to identify the

appropriate design approach.

A-9.23.13.2.(1)(a)(i) Heavy Construction. “Heavy construction” refers to buildings with tile roofs, stucco walls or floors

with concrete topping, or that are clad with directly-applied heavyweight materials.

Heavyweight construction assemblies increase the lateral load on the structure during an earthquake. Assemblies should be considered

as heavyweight where their average dead weight is as follows (an additional partition weight of 0.5 kPa per floor is assumed):

• floor: 0.5 to 1.5 kPa

• roof: 0.5 to 1.0 kPa

• wall (vertical area): 0.32 to 1.2 kPa

Table A-9.23.13.

Application of Lateral Load Requirements

Applicable

Requirements

Wind (HWP) Earthquake S

(0.2)

Low to Moderate High Extreme Low to Moderate High Extreme High Extreme

HWP < 0.80 kPa

0.80 ≤ HWP

< 1.20 kPa

HWP ≥

1.20 kPa

(0.2) ≤ 0.70

0.70 < S

(0.2)

≤ 1.8

(0.2) > 1.8

0.70 < S

(0.2)

≤ 1.8

(0.2) > 1.8

All Construction All Construction Heavy Construction

(1)

Light Construction

Design requirements in

9.23.16.2., 9.27., 9.29.

(2)

N/A N/A X N/A N/A N/A N/A

Bracing requirements

in 9.23.13.

XXN/AXX

(3)(4)

N/A X

(4)(5)

N/A

Part 4 or CWC Guide X X X X X X X X

X = requirements are applicable

Notes to Table A-9.23.13.:

(1) See Note A-9.23.13.2.(1)(a)(i).

(2) Requirements apply to exterior walls only.

(3) Requirements apply where lowest exterior frame walls support not more than one floor.

(4) All constructions may include the support of a roof in addition to the stated number of floors.

(5) Requirements apply where lowest exterior frame walls support not more than two floors.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.23.13.4. Braced Wall Bands. Article 9.23.13.4. specifies the required characteristics of braced wall bands and their

position in the building. Figures A-9.23.13.4.-A, A-9.23.13.4.-B and A-9.23.13.4.-C illustrate these requirements.

Figure A-9.23.13.4.-A

Braced wall bands in an example building section [Clauses 9.23.13.4.(1)(a), (b) and (d)]

EG00682A

braced wall band

braced wall panel

9.23.13.4.(1)(b):

braced wall band

max. 1.2 m wide

9.23.13.4.(1)(a):

braced wall band

full storey height

9.23.13.4.(1)(d):

braced wall band aligned

with braced wall bands on

storeys above and below

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.23.13.4.-B

Lapping bands and building perimeter within braced wall bands [Clause 9.23.13.4.(1)(c) and Sentence 9.23.13.4.(2)]

Figure A-9.23.13.4.-C

Braced wall band at change in floor level in split-level buildings [Sentence 9.23.13.4.(3)]

A-Table 9.23.13.5. Spacing of Braced Wall Bands and Braced Wall Panels. Identifying adjacent braced wall bands

and determining the spacing of braced wall panels and braced wall bands is not complicated where the building plan is orthogonal or

there are parallel braced wall bands: the adjacent braced wall band is the nearest parallel band. Figure Table A-9.23.13.5.-A

illustrates spacing.

EG00683A

9.23.13.4.(2):

building perimeter

within braced wall bands

9.23.13.4.(1)(c):

braced wall bands lap at both

ends with another braced wall

band so that the centre line of

one band extends to the far

side of the connecting band

braced wall band

braced wall panel

centre line of band

GG00171A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure Table A-9.23.13.5.-A

Spacing of parallel braced wall bands and spacing of braced wall panels

Identifying and Spacing Adjacent Non-Parallel Braced Wall Bands

Identifying the adjacent braced wall band and the spacing between braced wall bands is more complicated where the building plan is

not orthogonal.

Where the plan is triangular, all braced wall bands intersect with the subject braced wall band. The prescriptive requirements in Part 9

do not apply to these cases and the building must be designed according to Part 4 with respect to lateral load resistance.

Where the braced wall bands are not parallel, the adjacent band is identified as follows using Figure Table A-9.23.13.5.-B as an

example:

1. Determine the mid-point of the centre line of the subject braced wall band (A);

2. Project a perpendicular line from this mid-point (B);

3. The first braced wall band encountered is the adjacent braced wall band (C);

4. Where the projected line encounters an intersection point between two braced wall bands, either wall band may be identified as the

adjacent braced wall band (complex cases).

The spacing of non-parallel braced wall bands is measured as the greatest distance between the centre lines of the bands.

EG00684A

braced wall band

centre line of braced wall band

braced wall panel

A A

Where

A = distance between centre lines of adjacent braced wall bands

B = distance between panel edges

C = distance from end of braced wall band to end of first braced

wall panel

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure Table A-9.23.13.5.-B

Identification and spacing of adjacent non-parallel braced wall bands

A-9.23.13.5.(2) Perimeter Foundation Walls. Where the perimeter foundation walls in basements and crawl spaces extend

from the footings to the underside of the supported floor, these walls perform the same function as braced wall bands with braced wall

panels. All other braced wall bands in the basement or crawl space that align with bands with a wood-based bracing material on the

upper floors need to be constructed with braced wall panels, which must be made of a wood-based bracing material, masonry or

concrete. See Figure A-9.23.13.5.(2).

EG00685A

braced wall band

ntr

lin

aced

braced wall panel

spacing between adjacent

braced wall bands

Simple Cases

spacing

between

adjacent

braced

wall bands

Complex Cases

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.23.13.5.(2)

Braced wall bands in basements or crawl spaces with optional and required braced wall panels

EG00687A

braced wall band

centre line of braced wall band

braced wall panel with

ypsum board interior finish providin

required bracin

15 m

braced wall panel with OSB, waferboard, plywood or diagonal lumber providing required bracing

10 m

10 m 5 m

braced wall panels required in

one braced wall band in basement

< 15 m

10 m

4 m

braced wall panels not required in

braced wall band in basement

> 15 m

10 m

braced wall panels required in

braced wall band in basement

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.23.13.5.(3) Attachment of a Porch Roof to Exterior Wall Framing.

Figure A-9.23.13.5.(3)-A

Framing perpendicular to plane of wall (balloon construction)

end joists attached

to wall studs with

2 x 76 mm nails

roof sheathed with

structural wood panel or

diagonally sheathed lumber

end joists attached

to wall studs with

2 x 76 mm nails

lesser of 3.5 m

1/2 perpendicular

plan dimension

EG00695A

wall studs of the

main building’s

exterior braced

wall band

perpendicular plan

dimension

ledger attached

to wall studs to

resist gravity loads

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.23.13.5.(3)-B

Framing parallel to plane of wall

A-9.23.13.6.(5) and (6) Use of Gypsum Board Interior Finish to Provide Required Bracing. Braced wall panels

constructed with gypsum board provide less resistance to lateral loads than panels constructed with OSB, waferboard, plywood or

diagonal lumber; Sentence (5) therefore limits the use of gypsum board to interior walls. Sentence (6) further limits its use to provide

the required lateral resistance by requiring that walls not more than 15 m apart be constructed with panels made of wood or

wood-based sheathing. See Figure A-9.23.13.6.(5) and (6).

roof sheathed with

structural wood panel or

diagonally sheathed lumber

ledger attached

to wall studs to

support header beam

wall studs of the

main building’s

exterior braced

wall band

perpendicular plan

dimension

lesser of 3.5 m

1/2 perpendicular

plan dimension

EG00696A

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.23.13.6.(5) and (6)

Braced wall panels constructed of wood-based material

A-9.23.14.11.(2) Wood Roof Truss Connections. Sentence 9.23.14.11.(2) requires that the connections used in wood

roof trusses be designed in conformance with Subsection 4.3.1. and Sentence 2.2.1.2.(1) of Division C, which applies to all of Part 4,

requires that the designer be a professional engineer or architect skilled in the work concerned. This has the effect of requiring that the

trusses themselves be designed by professional engineers or architects. Although this is a departure from the usual practice in Part 9,

it is appropriate, since wood roof trusses are complex structures which depend on a number of components (chord members,

web members, cross-bracing, connectors) working together to function safely. This complexity precludes the standardization of truss

design into tables comprehensive enough to satisfy the variety of roof designs required by the housing industry.

A-9.23.15.2.(4) Water Absorption Test. A method for determining water absorption is described in ASTM D 1037,

“Evaluating Properties of Wood-Base Fiber and Particle Panel Materials.” The treatment to reduce water absorption may be

considered to be acceptable if a 300 mm × 300 mm sample when treated on all sides and edges does not increase in weight by more

than 6% when tested in the horizontal position.

A-9.23.15.4.(2) OSB. CSA O437.0, “OSB and Waferboard,” requires that Type O (aligned or oriented) panels be marked to

show the grade and the direction of face alignment.

A-9.24.3.2.(3) Framing Above Doors in Steel Stud Fire Separations.

Figure A-9.24.3.2.(3)

Steel stud header detail

EG00686A

braced wall band

centre line of braced wall band

braced wall panel with gypsum board interior finish providing required bracing

maximum 15 m maximum 15 m maximum 15 m

braced wall panel with OSB, waferboard, plywood or diagonal lumber providing required bracing

two screws - one at each

end of header track

gypsum board

2 tracks back to back

gypsum board

door frame

jack stud

EC01219A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.25.2.2.(2) Flame-Spread Ratings of Insulating Materials. Part 9 has no requirements for flame-spread ratings of

insulation materials since these are seldom exposed in parts of buildings where fires are likely to start. Certain of the insulating material

standards referenced in Sentence 9.25.2.2.(1) do include flame-spread rating criteria. These are included either because the industry

producing the product wishes to demonstrate that their product does not constitute a fire hazard or because the product is regulated by

authorities other than building authorities (e.g., “Hazardous Products Act”). However, the Code cannot apply such requirements to

some materials and not to others. Hence, these flame-spread rating requirements are excepted in referencing these standards.

A-9.25.2.3.(3) Position of Insulation. For thermal insulation to be effective, it must not be short-circuited by convective

airflow through or around the material. If low-density fibrous insulation is installed with an air space on both sides of the insulation,

the temperature differential between the warm and cold sides will drive convective airflow around the insulation. If foamed plastic

insulation is spot-adhered to a backing wall or adhered in a grid pattern to an air-permeable substrate, and is not sealed at the joints

and around the perimeter, air spaces between the insulation and the substrate will interconnect with spaces behind the cladding.

Any temperature or air pressure differential across the insulation will again lead to short circuiting of the insulation by airflow.

Thermal insulation must therefore be installed in full and continuous contact with the air barrier or another continuous component

with low air permeance. (See Note A-9.25.5.1.(1) for examples of low-air-permeance materials.)

A-9.25.2.4.(3) Loose-Fill Insulation in Existing Wood-Frame Walls. The addition of insulation into exterior walls of

existing wood-frame buildings increases the likelihood of damage to framing and cladding components as a result of moisture

accumulation. Many older homes were constructed with little or no regard for protection from vapour transmission or air leakage from

the interior. Adding thermal insulation will substantially reduce the temperature of the siding or sheathing in winter months,

possibly leading to condensation of moisture at this location.

Defects in exterior cladding, flashing and caulking could result in rain entering the wall cavity. This moisture, if retained by the added

insulation, could initiate the process of decay.

Steps should be taken therefore, to minimize these effects prior to the retrofit of any insulation. Any openings in walls that could

permit leakage of interior heated air into the wall cavity should be sealed. The inside surface should be coated with a low-permeability

paint to reduce moisture transfer by diffusion. Finally, the exterior siding, flashing and caulking should be checked and repaired if

necessary to prevent rain penetration.

A-9.25.2.4.(5) Loose-Fill Insulation in Masonry Walls. Typical masonry cavity wall construction techniques do not lend

themselves to the prevention of entry of rainwater into the wall space. For this reason, loose-fill insulation used in such space must be

of the water repellent type. A test for water-repellency of loose-fill insulation suitable for installation in masonry cavity walls can be

found in ASTM C 516, “Vermiculite Loose Fill Thermal Insulation.”

A-9.25.3.1.(1) Air Barrier Systems for Control of Condensation. The majority of moisture problems resulting from

condensation of water vapour in walls and ceiling/attic spaces are caused by the leakage of moist interior heated air into these spaces

rather than by the diffusion of water vapour through the building envelope.

Protection against such air leakage must be provided by a system of air-impermeable materials joined with leak-free joints. Generally,

air leakage protection can be provided by the use of air-impermeable sheet materials, such as gypsum board or polyethylene of

sufficient thickness, when installed with appropr

iate structural support. However, the integrity of the airtight elements in the air

barrier system can be compromised at the joints and here special care must be taken in design and construction to achieve an effective

air barrier system.

Although Section 9.25. refers separately to vapour barriers and airtight elements in the air barrier system, these functions in a wall or

ceiling assembly of conventional wood-frame construction are often combined as a single membrane that acts as a barrier against

moisture diffusion and the movement of interior air into insulated wall or roof cavities. Openings cut through this membrane, such as

for electrical boxes, provide opportunities for air leakage into concealed spaces, and special measures must be taken to make such

openings as airtight as possible. Attention must also be paid to less obvious leakage paths, such as holes for electric wiring, plumbing

installations, wall-ceiling and wall-floor intersections, and gaps created by shrinkage of framing members.

In any case, air leakage must be controlled to a level where the occurrence of condensation will be sufficiently rare, or the quantities

accumulated sufficiently small, and drying sufficiently rapid, to avoid material deterioration and the growth of mould and fungi.

Generally the location in a building assembly of the airtight element of the air barrier system is not critical; it can restrict air leakage

whether it is located near the outer surface of the assembly, near the inner surface or at some intermediate location. However, if a

material chosen to act as an airtight element in the air barrier system also has the characteristics of a vapour barrier (i.e., low

permeability to water vapour), its location must be chosen more carefully in order to avoid moisture problems.

(See Notes A-9.25.5.1.(1) and A-9.25.4.3.(2).)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

In some constructions, an airtight element in the air barrier system is the interior finish, such as gypsum board, which is sealed to

framing members and adjacent components by gaskets, caulking, tape or other methods to complete the air barrier system. In such

cases, special care in sealing joints in a separate vapour barrier is not critical. This approach often uses no separate vapour barrier but

relies on appropriate paint coatings to give the interior finish sufficient resistance to water vapour diffusion that it can provide the

required vapour diffusion protection.

The wording in Section 9.25. allows for such innovative techniques, as well as the more traditional approach of using a continuous

sheet, such as polyethylene, to act as an “air/vapour barrier.”

Further information can be found in CBD 231, “Moisture Problems in Houses” (Canadian Building Digest 231), by A.T. Hansen,

which is available from NRC.

A-9.25.3.4. and 9.25.3.6. Air Leakage and Soil Gas Control in Floors-on-ground. The requirement in

Sentence 9.25.3.3.(6) regarding the sealing of penetrations of the air barrier also applies to hollow metal and masonry columns

penetrating the floor slab. Not only the perimeters but also the centres of such columns must be sealed or blocked.

Figure A-9.25.3.4. and 9.25.3.6.-A

Dampproofing and soil gas control at foundation wall/floor junctions with solid walls

The requirement in Sentence 9.25.3.6.(6) regarding drainage openings in slabs can be satisfied with any of a number of proprietary

devices that prevent the entry of radon and other soil gases through floor drains. Some types of floor drains incorporate a trap that is

connected to a nearby tap so that the trap is filled every time the tap is used. This is intended to prevent the entry of sewer gas but

would be equally effective against the entry of radon and other soil gases.

Figure A-9.25.3.4. and 9.25.3.6.-B

Dampproofing and soil gas control at foundation wall/floor junctions with hollow walls

A-9.25.3.6.(2) and (3) Polyethylene Air Barriers under Floors-on-Ground. Floors-on-ground separating conditioned

space from the ground must be constructed to reduce the potential for the entry of air, radon or other soil gases. In most cases, this will

be accomplished by placing 0.15 mm polyethylene under the floor.

Finishing a concrete slab placed directly on polyethylene can, in many cases, cause problems for the inexperienced finisher. A rule of

finishing, whether concrete is placed on polyethylene or not, is to never finish or “work” the surface of the slab while bleed water is

present or before all the bleed water has risen to the surface and evaporated. If finishing operations are performed before all the bleed

water has risen and evaporated, surface defects such as blisters, crazing, scaling and dusting can result. In the case of slabs placed

directly on polyethylene, the amount of bleed water that may rise to the surface and the time required for it to do so are increased

compared to a slab placed on a compacted granular base. Because of the polyethylene, the excess water in the mix from the bottom

portion of the slab cannot bleed downward and out of the slab and be absorbed into the granular material below. Therefore, all bleed

water, including that from the bottom of the slab, must now rise through the slab to the surface. Quite often in such cases, finishing

operations are begun too soon and surface defects result.

exterior wall

dampproofing

(bituminous)

flexible sealant

slab dampproofing

and soil gas barrier

granular fill

EG00419B

exterior wall

dampproofing

(bituminous)

parging

flexible sealant

slab dampproofing

and soil gas barrier

granular fill

EG00419C

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

One solution that is often suggested is to place a layer of sand between the polyethylene and the concrete. However, this is not an

acceptable solution for the following reason: it is unlikely that the polyethylene will survive the slab pouring process entirely intact.

Nevertheless, the polyethylene will still be effective in retarding the flow of soil gas if it is in intimate contact with the concrete; soil gas

will only be able to penetrate where a break in the polyethylene coincides with a crack in the concrete. The majority of concrete cracks

will probably be underlain by intact polyethylene. On the other hand, if there is an intervening layer of a porous medium, such as

sand, soil gas will be able to travel laterally from a break in the polyethylene to the nearest crack in the concrete and the total system

will be much less resistant to soil gas penetration.

To reduce and/or control the cracking of concrete slabs, it is necessary to understand the nature and causes of volume changes of

concrete and in particular those relating to drying shrinkage. The total amount of water in a mix is by far the largest contributor to the

amount of drying shrinkage and resulting potential cracking that may be expected from a given concrete. The less total amount of

water in the mix, the less volume change (due to evaporation of water), which means the less drying shrinkage that will occur. To lessen

the volume change and potential cracking due to drying shrinkage, a mix with the lowest total amount of water that is practicable

should always be used. To lower the water content of a mix, superplasticizers are often added to provide the needed workability of the

concrete during the placing operation. Concretes with a high water-to-cementing-materials ratio usually have high water content

mixes. They should be avoided to minimize drying shrinkage and cracking of the slab. The water-to-cementing-materials ratio for

slabs-on-ground should be no higher than 0.55.

A-9.25.4.2.(2) Normal Conditions. The requirement for a 60 ng/Pa·s·m

vapour barrier stated in Sentence 9.25.4.2.(1) is

based on the assumption that the building assembly is subjected to conditions that are considered normal for typical residential

occupancies, and business and personal services occupancies.

However, where the intended use of an occupancy includes facilities or activities that will generate a substantial amount of moisture

indoors during the heating season, such as swimming pools, greenhouses, laundromats, and any continuous operation of hot tubs and

saunas, the building envelope assemblies would have to demonstrate acceptable performance levels in accordance with the

requirements in Part 5.

A-9.25.4.3.(2) Location of Vapour Barriers. Assemblies in which the vapour barrier is located partway through the

insulation meet the intent of this Article provided it can be shown that the temperature of the vapour barrier will not fall below the

dew point of the heated interior air.

A-9.25.5.1. Location of Low Permeance Materials.

Low Air- and Vapour-Permeance Materials and Implications for Moisture Accumulation

The location in a building assembly of a material with low air permeance is generally not critical; the material can restrict outward

movement of indoor air whether it is located near the outer surface of the assembly, near the inner surface, or at some

intermediate location, and such restriction of air movement is generally beneficial, whether or not the particular material is

designated as part of the air barrier system. However, if such a material also has the characteristics of a vapour barrier (i.e.low

permeability to water vapour), its location must be chosen more carefully in order to avoid moisture accumulation.

Any moisture from the indoor air that diffuses through the inner layers of the assembly or is carried by air leakage through those

layers may be prevented from diffusing or being transferred through the assembly by a low air- and vapour-permeance material.

This moisture transfer will usually not cause a problem if the material is located where the temperature is above the dew point of

the indoor air: the water vapour will remain as vapour, the humidity level in the assembly will come to equilibrium with that of

the indoor air, further accumulation of moisture will cease or stabilize at a low rate, and no harm will be done.

But if the low air- and vapour-permeance material is located where the temperature is below the dew point of the air at that

location, water vapour will condense and accumulate as water or ice, which will reduce the humidity level and encourage the

movement of more water vapour into the assembly. If the temperature remains below the dew point for any length of time,

significant moisture could accumulate. When warmer weather returns, the presence of a material with low water vapour

permeance can retard drying of the accumulated moisture. Moisture that remains into warmer weather can support the growth of

decay organisms.

Due consideration should be given to the properties and location of any material in the building envelope, including paints,

liquid-applied or sprayed-on and trowelled-on materials. It is recognized that constructions that include low air- and

vapour-permeance materials are acceptable, but only where these materials are not susceptible to damage from moisture or where

they can accommodate moisture, for example insulated concrete walls. Further information on the construction of basement walls

may be found in “Performance Guidelines for Basement Envelope Systems and Materials,” published by NRC-IRC.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Cladding

Different cladding materials have different vapour permeances and different degrees of susceptibility to moisture deterioration.

They are each installed in different ways that are more or less conducive to the release of moisture that may accumulate on the

inner surface. Sheet or panel-type cladding materials, such as metal sheet, have a vapour permeance less than 60 ng/(Pa·s·m

Sheet metal cladding that has lock seams also has a low air leakage characteristic and so must be installed outboard of a drained

and vented air space. Assemblies clad with standard residential vinyl or metal strip siding do not require additional protection as

the joints are not so tight as to prevent the dissipation of moisture.

Sheathing

Like cladding, sheathing materials have different vapour permeances and different degrees of susceptibility to moisture

deterioration.

Low-permeance sheathing may serve as the vapour barrier if it can be shown that the temperature of the interior surface of the

sheathing will not fall below that at which saturation will occur. This may be the case where insulating sheathing is used.

Thermal Insulation

Where low-permeance foamed plastic is the sole thermal insulation in a building assembly, the temperature of the inner surface of

this element will be close to the interior temperature. If the foamed plastic insulation has a permeance below 60 ng/Pa·s·m

, it can

fulfill the function of a vapour barrier to control condensation within the assembly due to vapour diffusion. However, where

low-permeance thermal insulating sheathing is installed on the outside of an insulated frame wall, the temperature of the inner

surface of the insulating sheathing may fall below the dew point; in this case, the function of vapour barrier has to be provided by

a separate building element installed on the warm side of the assembly.

Normal Conditions

The required minimum ratios given in Table 9.25.5.2. are based on the assumption that the building assembly is subjected to

conditions that are considered normal for typical residential occupancies, and business and personal services occupancies.

However, where the intended use of an occupancy includes facilities or activities that will generate a substantial amount of

moisture indoors during the heating season, such as swimming pools, greenhouses, the operation of a laundromat or any

continuous operation of hot tubs and saunas, the building envelope assemblies would have to demonstrate acceptable

performance levels in accordance with the requirements in Part 5.

A-9.25.5.1.(1) Air and Vapour Permeance Values. The air leakage characteristics and water vapour permeance values for

a number of common materials are given in Table A-9.25.5.1.(1). These values are provided on a generic basis; proprietary products

may have values differing somewhat from those in the Table (consult the manufacturers’ current data sheets for their products’ values).

The values quoted are for the material thickness listed. Water vapour permeance is inversely proportional to thickness: therefore,

greater thicknesses will have lower water vapour permeance values.

Table A-9.25.5.1.(1)

Air and Vapour Permeance Values

(1)

Forming Part of Note A-9.25.5.1.(1)

Material

Air Leakage Characteristic, L/(s·m

)

at 75 Pa(Air Permeance)

Water Vapour Permeance,

(Dry Cup) ng/(Pa·s·m

)

Sheet and panel-type materials

12.7-mm gypsum board 0.02 2600

• painted (1 coat primer) negligible 1300

• painted (1 coat primer + 2 coats latex paint) negligible 180

12.7-mm foil-backed gypsum board negligible negligible

12.7-mm gypsum board sheathing 0.0091 1373

6.4-mm plywood 0.0084 23-74

11-mm oriented strandboard 0.0108 44 (range)

12.5-mm cement board 0.147 590

plywood (from 9.5 mm to 18 mm) negligible-0.01 40-57

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

fibreboard sheathing 0.012 - 1.91 100 - 2900

17-mm wood sheathing high-depends on no. of joints 982

Insulation

27-mm foil-faced polyisocyanurate negligible 4.3

27-mm paper-faced polyisocyanurate negligible 61.1

25-mm extruded polystyrene negligible 23 - 92

25-mm expanded polystyrene (Type 2) 0.0214 86 - 160

fibrous insulations very high very high

25-mm polyurethane spray foam – low density 0.011 894 - 3791

25-mm polyurethane spray foam–medium density negligible 96

(2)

Membrane-type materials

asphalt-impregnated paper (10 min paper) 0.0673 370

asphalt-impregnated paper (30 min paper) 0.4 650

asphalt-impregnated paper (60 min paper) 0.44 1800

water-resistive barriers (9 materials) negligible - 4.3 30 - 1200

0.15-mm polyethylene negligible 1.6 - 5.8

asphalt-saturated felt (#15) 0.153 290

building paper 0.2706 170 - 1400

spun-bonded polyolefin film (expanded) 0.9593 3646

Other materials

brick (6 materials) negligible 102 - 602

metal negligible negligible

mortar mixes (4 materials) negligible 13 - 690

stucco negligible 75 - 240

50-mm reinforced concrete (density: 2 330 kg/m

) negligible 23

Notes to Table A-9.25.5.1.(1):

(1) Air leakage and vapour permeance values derived from:

• Bombaru, D., Jutras, R. and Patenaude, A. “Air Permeance of Building Materials.” Summary Report prepared by AIR-INS Inc. for Canada Mortgage and Housing

Corporation, Ottawa, 1988. Values indicate properties of tested materials only; values for specific products may vary significantly.

• “Details of Air Barrier Systems for Houses.” Tarion Warranty Corporation (formerly Ontario New Home Warranty Program), Toronto, 1993.

• Kumaran, M.K., et al., ASHRAE Research Report 1018 RP, A Thermal and Moisture Transport Property Database for Common Building and Insulating Materials.

• Kumaran, M.K., Lackey, J., Normandin, N., van Reenen, D., Tariku, F., Summary Report from Task 3 of MEWS Project at the Institute for Research in

Construction-Hygrothermal Properties of Several Building Materials, IRC-RR-110, March 2002.

• Mukhopadhyaya, P., Kumaran, M.K., et al., Hygrothermal Properties of Exterior Claddings, Sheathings Boards, Membranes and Insulation Materials for Building

Envelope Design, Proceedings of Thermal Perfomance of the Exterior Envelopes of Whole Building X, Clearwater, Florida, December 2-7, 2007, pp. 1-16

(NRCC-50287).

(2) This water vapour permeance value is for a 25-mm-thick core layer of medium-density polyurethane spray foam. When installed in the field, a low permeance resin layer

forms where the foam is in contact with the substrate. The water vapour permeance of the installed foam, were it measured including the resin layer, would therefore likely

be lower than the value listed in the Table.

Table A-9.25.5.1.(1) (continued)

Air and Vapour Permeance Values

(1)

Forming Part of Note A-9.25.5.1.(1)

Material

Air Leakage Characteristic, L/(s·m

)

at 75 Pa(Air Permeance)

Water Vapour Permeance,

(Dry Cup) ng/(Pa·s·m

)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.25.5.1.(1)(a)(ii) Reduced Potential for Condensation in the Building Envelope. The requirements in

Article 9.25.5.2. aim to reduce the risk of condensation being introduced into wall assemblies due to the water vapour permeance of

the outboard materials. Research has confirmed that the reduced condensation potential of exterior continuous insulation with a

thermal resistance of at least 0.7 (m

·K)/W and a water vapour permeance between 30 and 1800 ng/(Pa·s·m

) compares to reference

assemblies without exterior insulation in a given geographic location and climatic exposure.

A-9.25.5.1.(3) Wood-based Sheathing Materials. Wood-based sheathing materials, such as plywood and OSB, that are

not more than 12.5 mm thick are exempt from complying with Sentence 9.25.5.1.(1) because wood has an adaptive vapour

permeance based on relative humidity: it has a low vapour permeance in an environment with low relative humidity and a higher

vapour permeance in an environment with high relative humidity (see Figure A-9.25.5.1.(3)). This adaptive vapour permeance means

that wood-based materials located on the outboard side of an assembly in winter, where the RH is typically 75% or higher, are

relatively vapour-open, thus allowing greater vapour movement. The same wood-based material located on the inboard side of an

assembly, where the RH is typically much lower in winter, has a low vapour permeance, thus mitigating the movement of vapour.

Figure A-9.25.5.1.(3)

Adaptive water vapour permeance of wood-based sheathing materials

2000

1800

1600

1400

1200

1000

800

600

400

200

02040 60 80 100

Relative humidity, %

Water vapour permeance, ng/Pa·s·m

OSB (11 mm thick with a density of 650 kg/m

)

plywood (15 mm thick with a density of 600 kg/m

)

range of extruded polystyrene products (25 mm thick)

EG01392A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.25.5.2. Assumptions Followed in Developing Table 9.25.5.2. Article 9.25.5.2. specifies that a low air- and

vapour-permeance material must be located on the warm face of the assembly, outboard of a vented air space, or within the assembly

at a position where its inner surface is likely to be warm enough for most of the heating season such that no significant accumulation

of moisture will occur. This last position is defined by the ratio of the thermal resistance values outboard and inboard of the innermost

impermeable surface of the material in question.

The design values given in Table 9.25.5.2. are based on the assumption that the building includes a mechanical ventilation system

(between 0.3 and 0.5 air changes per hour), a 60 ng/Pa·s·m

vapour barrier, and an air barrier (values between 0.024 and 0.1 L/sm

through the assembly were used). The moisture generated by occupants and their use of bathrooms, cleaning, laundry and kitchen

appliances was assumed to fall between 7.5 and 11.5 L per day.

It has been demonstrated through modelling under these conditions that assemblies constructed according to the requirements in

Table 9.25.5.2. do not lead to moisture accumulation levels that may lead to deterioration as long as the average monthly vapour

pressure difference between the exterior and interior sides over the heating season does not increase above 750 Pa, which would

translate into an interior relative humidity of 35% in colder climates and 60% in mild climates.

Health Canada recommends an indoor relative humidity between 35% and 50% for healthy conditions. ASHRAE accepts a 30% to

60% range. Environments that are much drier tend to exacerbate respiratory problems and allergies; more humid environments tend

to support the spread of microbes, moulds and dust mites, which can adversely affect health.

In most of Canada in the winter, indoor RH is limited by the exterior temperature and the corresponding temperature on the inside of

windows. During colder periods, indoor RH higher than 35% will cause significant condensation on windows. When this occurs,

occupants are likely to increase the ventilation to remove excess moisture. Although indoor RH may exceed 35% for short periods

when the outside temperature is warmer, the criteria provided in Table 9.25.5.2. will still apply. Where higher relative humidities are

maintained for extended periods in these colder climates, the ratios listed in the Table may not provide adequate protection.

Some occupancies require that RH be maintained above 35% throughout the year, and some interior spaces support activities such as

swimming that create high relative humidities. In these cases, Table 9.25.5.2. cannot be used and the position of the materials must be

determined according to Part 5.

It should be noted that Part 9 building envelopes in regions with colder winters have historically performed acceptably when the

interior RH does not exceed 35% over most of the heating season. With tighter building envelopes, it is possible to raise interior RH

levels above 35%. There is no information, however, on how Part 9 building envelopes will perform when exposed to these higher

indoor RH levels for extended periods during the heating season over many years. Operation of the ventilation system, as intended to

remove indoor pollutants, will maintain the lower RH levels as necessary.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Calculating Inboard to Outboard Thermal Resistance

Figure A-9.25.5.2.

Example of a wall section showing thermal resistance inboard and outboard of a plane of low air and vapour permeance

The method of calculating the inboard to outboard thermal resistance ratio is illustrated in Figure A-9.25.5.2. The example wall

section shows three planes where low air- and vapour-permeance materials have been installed. A vapour barrier, installed to meet the

requirements of Subsection 9.25.4., is on the warm side of the insulation consistent with Clause 9.25.5.2.(1)(a) and

Sentences 9.25.4.1.(1) and 9.25.4.3.(2). The vinyl siding has an integral drained and vented air space consistent with

Clause 9.25.5.2.(1)(c). The position of the interior face of the low-permeance insulating sheathing, however, must be reviewed in

terms of its thermal resistance relative to the overall thermal resistance of the wall, and the climate where the building is located.

Comparing the RSI ratio from the example wall section with those in Table 9.25.5.2. indicates that this wall would be acceptable in

areas with Celsius degree-day values up to 7999, which includes, for example, Whitehorse, Fort McMurray, Yorkton, Flin Flon,

Geraldton, Val-d’Or and Wabush. (Degree-day values for various locations in Canada are provided in Appendix C.)

A similar calculation would indicate that, for a similar assembly with a 140 mm stud cavity filled with an RSI 3.52 batt, the ratio

would be 0.28. Thus such a wall could be used in areas with Celsius degree-day values up to 4999, which includes, for example,

Cranbrook, Lethbridge, Ottawa, Montreal, Fredericton, Sydney, Charlottetown and St. John’s.

plane of low air and vapour permeance

air film

13 mm

gypsum board

metal or vinyl siding

insulating

sheathing

glass fibre batt in

89 mm stud cavity

air film

EG00382C

Type 2 vapour

barrier

Ratio

= 0.44

1.02

2.31

RSI value

T otal RSI

value

0.12

0.08

Inboard

2.11

2.31

Outboard

0.03 0.12

0.87

1.02

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Similarly, if half the thickness of the same low-permeance sheathing were used, the ratio with an 89 mm cavity would be 0.25,

permitting its use in areas with Celsius degree-day values up to 4999. The ratio with a 140 mm cavity would be 0.16; thus this

assembly could not be used anywhere, since this ratio is below the minimum permitted in Table 9.25.5.2.

Table A-9.25.5.2. shows the minimum thicknesses of low-permeance insulating sheathing necessary to satisfy Article 9.25.5.2. in

various degree-day zones for a range of resistivity values of insulating sheathing. These thicknesses are based on the detail shown in

Figure A-9.25.5.2. but could also be used with cladding details, such as brick veneer or wood siding, which provide equal or greater

outboard thermal resistance.

References

(1) “Exposure Guidelines for Residential Indoor Air Quality,” Environmental Health Directorate, Health Protection Branch, Health Canada, Ottawa, April 1987 (Revised July 1989).

(2) ANSI/ASHRAE 62, “Ventilation for Acceptable Indoor Air Quality.”

A-9.26.1.1.(1) Platforms that Effectively Serve as Roofs. Decks, balconies, exterior walkways and similar exterior

surfaces effectively serve as roofs where these platforms do not permit the free drainage of water through the deck. When water is

driven by wind across the deck (roof) surface, it can be driven upward when it encounters an interruption.

A-9.26.2.3.(4) Fasteners for Treated Shingles. Where shingles or shakes have been chemically treated with a preservative

or a fire retardant, the fastener should be of a material known to be compatible with the chemicals used in the treatment.

A-9.26.4.1. Junctions between Roofs and Walls or Guards. Drainage of water from decks and other platforms that

effectively serve as roofs will be blocked by walls, and blocked or restricted by guards where significant lengths and heights of material

are connected to the deck. Without proper flashing at such roof-wall junctions or roof-guard junctions, water will generally leak into

the adjoining constructions and can penetrate into supporting constructions below. Exceptions include platforms where waterproof

curbs of sufficient height are cast-in or where the deck and wall or guard are unit-formed. In these cases, the monolithic deck-wall or

deck-guard junctions will minimize the likelihood of water ingress. (See also Note A-9.26.1.1.(1).)

A-9.26.17.1.(1) Installation of Concrete Roof Tiles. Where concrete roof tiles are to be installed, the dead load imposed

by this material should be considered in determining the minimum sizes and maximum spans of the supporting roof members.

A-9.27.1.1.(5) EIFS on Walls with Cold-Formed Steel Stud Framing. While Part 9 permits the installation of exterior

insulation finish systems on walls with cold-formed steel stud framing, the design of loadbearing steel walls is outside the scope of

Part 9 and is addressed in Part 4 (see Sentence 9.24.1.1.(2)).

Table A-9.25.5.2.

Minimum Thicknesses of Low-Permeance Insulating Sheathing

Forming Part of Note A-9.25.5.2.

Celsius Heating

Degree-days

Min.

RSI

Ratio

38 × 89 Framing 38 × 140 Framing

Min. Outboard

Thermal

Resistance, RSI

Min. Sheathing Thickness, mm

Min. Outboard

Thermal

Resistance, RSI

Min. Sheathing Thickness, mm

Sheathing Thermal Resistance, RSI/mm Sheathing Thermal Resistance, RSI/mm

0.0300 0.0325 0.0350 0.0400 0.0300 0.0325 0.0350 0.0400

≤ 4999 0.20 0.46 1010 9 8 0.72 19171614

5000 to 5999 0.30 0.69 18 17 16 14 1.07 31 28 26 23

6000 to 6999 0.35 0.81 22 20 19 16 1.25 37 34 32 28

7000 to 7999 0.40 0.92 26 24 22 19 1.43 43 39 37 32

8000 to 8999 0.50 1.16 34 31 29 25 1.79 55 50 47 41

9000 to 9999 0.55 1.27 37 34 32 28 1.97 61 56 52 45

10000 to 10999 0.60 1.39 41 38 35 31 2.15 67 61 57 50

11000 to 11999 0.65 1.50 45 42 39 34 2.33 73 67 62 54

≥ 12000 0.75 1.73 53 49 45 40 2.69 85 78 72 63

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.27.2. Required Protection from Precipitation. Part 5 and Part 9 of the NBC recognize that mass walls and

face-sealed, concealed barrier and rainscreen assemblies have their place in the Canadian context.

Mass walls are generally constructed of cast-in-place concrete or masonry. Without cladding or surface finish, they can be exposed to

precipitation for a significant period before moisture will penetrate from the exterior to the interior. The critical characteristics of these

walls are related to thickness, mass, and moisture transfer properties, such as shedding, absorption and moisture diffusivity.

Face-sealed assemblies have only a single plane of protection. Sealant installed between cladding elements and other envelope

components is part of the air barrier system and is exposed to the weather. Face-sealed assemblies are appropriate where it can be

demonstrated that they will provide acceptable performance with respect to the health and safety of the occupants, the operation of

building services and the provision of conditions suitable for the intended occupancy. These assemblies, however, require more

intensive, regular and ongoing maintenance, and should only be selected on the basis of life-cycle costing considering the risk of failure

and all implications should failure occur. Climate loads such as wind-driven rain, for example, should be considered. Face-sealed

assemblies are not recommended where the building owner may not be aware of the maintenance issue or where regular maintenance

may be problematic.

Concealed barrier assemblies include both a first and second plane of protection. The first plane comprises the cladding, which is

intended to handle the majority of the precipitation load. The second plane of protection is intended to handle any water that

penetrates the cladding plane. It allows for the dissipation of this water, primarily by gravity drainage, and provides a barrier to further

ingress.

Like concealed barrier assemblies, rainscreen assemblies include both a first and second plane of protection. The first plane comprises

the cladding, which is designed and constructed to handle virtually all of the precipitation load. The second plane of protection is

designed and constructed to handle only very small quantities of incidental water; composition of the second plane is described in

Note A-9.27.3.1. In these assemblies, the air barrier system, which plays a role in controlling precipitation ingress due to air pressure

difference, is protected from the elements. (See Figure A-9.27.2.)

Figure A-9.27.2.

Generic rainscreen assemblies

second plane

of protection

(air space and

sheathing

membr

ane)

inner

boundary of

second

plane of

protection

heat, air and

apour control

elements with

structural elements

and finishes

(a)

second plane

of protection

(insulating

sheathing)

inner

boundar

y of

second

plane of

protection

heat, air and

vapour control

elements with

structural elements

and finishes

(b)

second plane

of protection

(2 layers

of sheathing

membr

ane)

inner

boundary of

second

plane of

protection

heat, air and

vapour control

elements with

structural elements

and finishes

(c)

EC02060A

rain penetration

control elements

rain penetration

control elements

rain penetration

control elements

first plane of

protection

(cladding)

first plane of

protection

(cladding)

first plane of

protection

(composite

cladding)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

The cladding assembly described in Sentence 9.27.2.2.(4) is a basic rainscreen assembly. This approach is required for residential

buildings where a higher level of ongoing performance is expected without significant maintenance. This approach, however,

is recommended in all cases.

The cladding assemblies described in Sentence 9.27.2.2.(5) are also rainscreen assemblies. The assembly described in

Clause 9.27.2.2.(1)(c) is again a basic rainscreen assembly. A wall with a capillary break as described in Clause 9.27.2.2.(1)(a) is an

open rainscreen assembly. Walls with a capillary break as described in Clause 9.27.2.2.(1)(b) have been referred to as drainscreen

assemblies.

A-9.27.2.1.(1) Minimizing Precipitation Ingress. The total prevention of precipitation ingress into wall assemblies is

difficult to achieve and, depending on the wall design and construction, may not be absolutely necessary. The amount of moisture that

enters a wall, and the frequency with which this occurs, must be limited. The occurrence of ingress must be sufficiently rare,

accumulation sufficiently small and drying sufficiently rapid to prevent the deterioration of moisture-susceptible materials and the

growth of fungi.

A-9.27.2.2. Required Levels of Protection from Precipitation. Precursors to Part 9 and all editions of the Code

containing a Part 9 applying to housing and small buildings included a performance-based provision requiring that cladding provide

protection from the weather for inboard materials. Industry requested that Part 9 provide additional guidance to assist in determining

the minimum levels of protection from precipitation to be provided by cladding assemblies. As with all requirements in the Code,

the new requirements in Article 9.27.2.2. describe the minimum cladding assembly configuration. Designers must still consider local

accepted good practice, demonstrated performance and the specific conditions to which a particular wall will be exposed when

designing or selecting a cladding assembly.

Capillary Breaks

The properties that are necessary for a material or assembly to provide a capillary break, and quantitative values for those

properties, have not been defined. Among the material properties that need to be addressed are water absorption and susceptibility

to moisture-related deterioration. Among the assembly characteristics to be considered are bridging of spaces by water droplets,

venting and drainage.

Clause 9.27.2.2.(1)(a) describes the capillary break configuration typical of open rainscreen construction. The minimum 9.5 mm

will avoid bridging of the space by water droplets and allow some construction tolerance.

Clause 9.27.2.2.(1)(b) describes a variation on the typical open rainscreen configuration. Products used to provide the capillary

break include a variety of non-moisture-susceptible, open-mesh materials.

Clause 9.27.2.2.(1)(c) describes a configuration that is typical of that provided by horizontal vinyl and metal siding, without

contoured insulating backing. The air space behind the cladding components and the loose installation reduce the likelihood of

moisture becoming trapped and promote drying by airflow.

Clause 9.27.2.2.(1)(d) recognizes the demonstrated performance of masonry cavity walls and masonry veneer walls.

Moisture Index

The moisture index (MI) for a particular location reflects both the wetting and drying characteristics of the climate and

depends on

• annual rainfall, and

• the temperature and relative humidity of the outdoor ambient air.

MI values are derived from detailed research and calculations.

Due to a lack of definitive data, the MI values identified in Sentence 9.27.2.2.(5), which trigger exceptions to or additional

precipitation protection, are based on expert opinion. Designers should consider local experience and demonstrated performance

when selecting materials and assemblies for protection from precipitation. For further information on MI, see Appendix C.

A-9.27.3.1. Second Plane of Protection.

As specified in Sentence 9.27.3.1.(1), the second plane of protection

consists of

a drainage plane with an appropriate material serving as the inner boundary and flashing to dissipate rainwater or meltwater to

the exterior.

Drainage Plane

Except for masonry walls, the simplest configuration of a drainage plane is merely a vertical interface between materials that will

allow gravity to draw the moisture down to the flashing to allow it to dissipate to the exterior. It does not necessarily need to be

constructed as a clear drainage space (air space).

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

For masonry walls, an open rainscreen assembly is required; that is, an assembly with first and second planes of protection where

the drainage plane is constructed as a drained and vented air space. Such construction also constitutes best practice for walls other

than masonry walls.

Section 9.20. requires drainage spaces of 25 mm for masonry veneer walls and 50 mm for cavity walls. In other than masonry

walls, the drainage space in an open rainscreen assembly should be at least 10 mm deep. Drainage holes must be designed in

conjunction with the flashing.

Sheathing Membrane

The sheathing membrane described in Article 9.27.3.2. is not a waterproof material. When installed to serve as the inner

boundary of the second plane of protection, and when that plane of protection includes a drainage space at least 9.5 mm deep,

the performance of the identified sheathing membrane has been demonstrated to be adequate. This is because the material is

expected to have to handle only a very small quantity of water that penetrates the first plane of protection.

If the 9.5 mm drainage space is reduced or interrupted, the drainage capacity and the capillary break provided by the space will be

reduced. In these cases, the material selected to serve as the inner boundary may need to be upgraded to provide greater water

resistance in order to protect moisture-susceptible materials in the backing wall.

Appropriate Level of Protection

It is recognized that many cladding assemblies with no space or with discontinuous space behind the cladding, and with the

sheathing membrane material identified in Article 9.27.3.2., have provided acceptable performance with a range of precipitation

loads imposed on them. Vinyl and metal strip siding, and shake and shingle cladding, for example, are installed with

discontinuous drained spaces, and have demonstrated acceptable performance in most conditions. Lapped wood and composite

strip sidings, depending on their profiles, may or may not provide discontinuous spaces, and generally provide little drainage.

Cladding assemblies with limited drainage capability that use a sheathing membrane meeting the minimum requirements are not

recommended where they may be exposed to high precipitation loads or where the level of protection provided by the cladding is

unknown or questionable. Local practice with demonstrated performance should be considered. (See also Article 9.27.2.2. and

Note A-9.27.2.2.)

A-9.27.3.4.(2) Detailing of Joints in Exterior Insulating Sheathing. The shape of a joint is critical to its ability to shed

water. Tongue and groove, and lapped joints can shed water if oriented correctly. Butt joints can drain to either side and so should not

be used unless they are sealed. However, detailing of joints requires attention not just to the shape of the joint but also to the materials

that form the joint. For example, even if properly shaped, the joints in insulating sheathing with an integral sheathing membrane

could not be expected to shed water if the insulating material absorbs water, unless the membrane extends through the joints.

A-9.27.3.5.(1) Sheathing Membranes in lieu of Sheathing. Article 9.23.17.1., Required Sheathing, indicates that

sheathing must be installed only where the cladding requires intermediate fastening between supports (studs) or where the cladding

requires a solid backing. Cladding such as brick or panels would be exempt from this requirement and in these cases a double layer of

sheathing membrane would generally be needed. The exception (Article 9.27.3.6.) applies only to those types of cladding that provide

a face seal to the weather.

A-9.27.3.6. Sheathing Membrane under Face Sealed Cladding. The purpose of sheathing membrane on walls is to

reduce air infiltration and to control the entry of wind-driven rain. Certain types of cladding consisting of very large sheets

or panels

with well-

sealed joints will perform this function, eliminating the need for sheathing membrane. This is true of the metal cladding

with lock-seamed joints sometimes used on mobile homes. However, it does not apply to metal or plastic siding applied in narrow

strips which is intended to simulate the appearance of lapped wood siding. Such material does not act as a substitute for sheathing

membrane since it incorporates provision for venting the wall cavity and has many loosely-fitted joints which cannot be counted on to

prevent the entry of wind and rain.

Furthermore, certain types of sheathing systems can perform the function of the sheathing membrane. Where it can be demonstrated

that a sheathing material is at least as impervious to air and water penetration as sheathing membrane and that its jointing system

results in joints that are at least as impervious to air and water penetration as the material itself, sheathing membrane may be omitted.

A-9.27.3.8.(1) Required Flashing.

Horizontal Offsets

Where a horizontal offset in the cladding is provided by a single cladding element, there is no joint between the offset and the

cladding above. In this case, and provided the cladding material on the offset provides effective protection for the construction

below, flashing is not required.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Changes in Substrate

In certain situations, flashing should be installed at a change of substrate: for example, where stucco cladding is installed on a

wood-frame assembly, extending down over a masonry or cast-in-place concrete foundation and applied directly to it. Such an

application does not take into account the potential for shrinkage of the wood frame and cuts off the drainage route for moisture

that may accumulate behind the stucco on the frame construction.

Figure A-9.27.3.8.(1)

Flashing at change in substrate

A-9.27.3.8.(3) Flashing over Curved-Head Openings. The requirement for flashing over openings depends on the

vertical distance from the top of the trim over the opening to the bottom of the eave compared to the horizontal projection of the eave.

In the case of curved-head openings, the vertical distance from the top of the trim increases as one moves away from the centre of the

opening. For these openings, the top of the trim must be taken as the lowest height before the trim becomes vertical.

(See Figure A-9.27.3.8.(3).)

Figure A-9.27.3.8.(3)

Flashing over curved-head openings

flashing

omitted

required

flashing

wood-frame

construction

EG02061B

bottom of eave

vertical distance

from bottom of

eave to top of trim

top of trim for

curved-head

openings

EC02062A

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.27.3.8.(4) Flashing Configuration and Positive Drainage.

Flashing Configuration

A 6% slope is recognized as the minimum that will provide effective flashing drainage. The 10 mm vertical lap over the building

element below and the 5 mm offset are prescribed to reduce transfer by capillarity and surface tension. Figure A-9.27.3.8.(4)

illustrates two examples of flashing configurations.

Figure A-9.27.3.8.(4)

Examples of flashing configurations showing upstands, horizontal offsets and vertical laps

Maintaining Positive Slope

Sentence 9.27.3.8.(4) requires that the minimum 6% flashing slope remain after expected shrinkage of the building frame.

Similarly, Sentence 9.26.3.1.(4) requires that a positive slope remain on roofs and similar constructions after expected shrinkage

of the building frame.

For Part 9 wood-frame constructions, expected wood shrinkage can be determined based on the average equilibrium moisture

content (MC) of wood, within the building envelope assembly, in various regions of the Province (see Table A-9.27.3.8.(4)).

For three-storey constructions to which Part 9 applies, cumulative longitudinal shrinkage is negligible. Shrinkage need only be

calculated for horizontal framing members using the following formula (from CWC 1997, “Introduction to Wood Building

Technology”):

Shrinkage = (total horizontal member height) × (initial MC – equilibrium MC) × (.002)

Table A-9.27.3.8.(4)

Equilibrium Moisture Content for Wood

Forming Part of Note A-9.32.3.1.(1)

Regions Equilibrium MC, %

(1)

British Columbia and Atlantic Canada 10

Ontario and Quebec 8

Prairies and the North 7

Notes to Table A-9.27.3.8.(4):

(1) CWC 2000, “Wood Reference Handbook.”

EC02063A

50-mm upstand

10-mm lap over

element below

5-mm offset

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.27.3.8.(5) Protection against Precipitation Ingress at the Sill-to-Cladding Joint. Many windows are

configured in such a way that a line of sealant is the only protection against water ingress at the sill-to-cladding joint – a location that

is exposed to all of the water that flows down the window. In the past, many windows were constructed with self-flashing sills –

sills that extend beyond the face of the cladding and have a drip on the underside to divert water away from the sill-to-cladding joint.

This sill configuration was considered to be accepted good practice and is recognized today as providing a degree of redundancy in

precipitation protection.

Self-flashing sills are sills that

• slope toward the exterior where the sills have an upward facing surface that extends beyond the jambs,

• where installed over a masonry sill, extend not less than 25 mm beyond the inner face of that sill,

• incorporate a drip positioned not less than 5 mm outward from the outer face of the cladding below or not less than 15 mm beyond

the inner edge of a masonry sill, and

• terminate at the jambs or, where the face of the jambs is not at least flush with the face of the cladding and the sills extend beyond

the jambs, incorporate end dams sufficiently high to protect against overflow in wind-driven rain conditions.

A wind pressure of 10 Pa can raise water 1 mm. Thus, for example, if a window is exposed to a driving rain wind pressure of 200 Pa,

end dams should be at least 20 mm high.

Figure A-9.27.3.8.(5)

Examples of configurations of self-flashing sills

A-9.27.4.2.(1) Selection and Installation of Sealants. Analysis of many sealant joint failures indicates that the majority

of failures can be attributed to improper joint preparation and deficient installation of the sealant and various joint components.

The following ASTM guidelines describe several aspects that should be considered when applying sealants in unprotected

environments to achieve a durable application:

• ASTM C 1193, “Use of Joint Sealants,”

• ASTM C 1299, “Selection of Liquid-Applied Sealants,” and

• ASTM C 1472, “Calculating Movement and Other Effects When Establishing Sealant Joint Width.”

The sealant manufacturer’s literature should always be consulted for recommended procedures and materials.

A-9.27.9.2.(3) Grooves in Hardboard Cladding. Grooves deeper than that specified may be used in thicker cladding

providing they do not reduce the thickness to less than the required thickness minus 1.5 mm. Thus for type 1 or 2 cladding, grooves

must not reduce the thickness to less than 4.5 mm or 6 mm depending on method of support, or to less than 7.5 mm for

type 5 material.

A-9.27.10.2.(2) Thickness of Grade O-2 OSB. In using Table 9.27.8.2. to determine the thickness of Grade O-2 OSB

cladding, substitute “face orientation” for “face grain” in the column headings.

A-9.27.11.1.(3) and (4) Material Standards for Aluminum Cladding. Compliance with Sentence 9.27.11.1.(3) and

CAN/CGSB-93.2-M, “Prefinished Aluminum Siding, Soffits, and Fascia, for Residential Use,” is required for aluminum siding that is

installed in horizontal or vertical strips. Compliance with Sentence 9.27.11.1.(4) and CAN/CGSB-93.1-M, “Sheet, Aluminum Alloy,

Prefinished, Residential,” is required for aluminum cladding that is installed in large sheets.

25-mm extension

beyond inner

face of masonry sill

6% slope

drip positioned 5 mm

beyond cladding or

15 mm beyond inner

face of masonry sill

EG02064A

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.27.13.1.(1) Geometrically Defined Drainage Cavity. “Geometrically defined drainage cavity” (GDDC) refers to the

channels, grooves or profiles cut into the insulation backing of an EIFS panel for the purpose of providing a way for water that gets

behind the system to drain out. The channels, grooves or profiles of one panel need to connect to the channels, grooves or profiles of

adjacent panels in order for drainage to occur consistently and uniformly across the entire EIFS. While the size of a channel, groove or

profile can be verified by inspecting a single panel, the intent of Sentence 9.27.13.1.(1) is that the required drainage capacity be

achieved across the entire system.

Additional information on the design and installation of EIFS can be found in

• the “EIFS Practice Manual,” published by the EIFS Council of Canada, and

• the manufacturer’s literature.

Figure A-9.27.13.1.(1)

Geometrically defined drainage cavity

A-9.27.13.2.(2)(a) Substrates for Exterior Insulation Finish Systems. The list of acceptable substrates for each type

of EIFS can be found in a system’s respective test report to CAN/ULC-S716.1, “Exterior Insulation and Finish Systems (EIFS) –

Materials and Systems”; however, the following substrates are generally considered acceptable:

• minimum 11 mm thick exposure 1 OSB classified as PS2 exterior wall sheathing

• minimum 11 mm thick exterior-rated plywood sheathing

• minimum 12.7 mm thick exterior gypsum sheathing conforming to ASTM C 1177/C 1177M, “Glass Mat Gypsum Substrate for

Use as Sheathing”

• cementitious panels

• fibre-cement panels

• concrete block

• clay masonry

• cast-in-place concrete

Note that, in some cases, the list of acceptable substrates may be limited by the EIFS manufacturer.

A-Table 9.28.4.3. Stucco Lath. Paper-backed welded wire lath may also be used on horizontal surfaces provided its

characteristics are suitable for such application.

A-9.30.1.2.(1) Water Resistance. In some areas of buildings, water and other substances may frequently be splashed or

spilled onto the floor. It is preferable, in such areas, that the finish flooring be a type that will not absorb moisture or permit it to pass

through; otherwise, both the flooring itself and the subfloor beneath it may deteriorate. Also, particularly in food preparation areas and

bathrooms, unsanitary conditions may be created by the absorbed moisture. Where absorbent or permeable flooring materials are used

in these areas, they should be installed in such a way that they can be conveniently removed periodically for cleaning or replacement,

i.e., they should not be glued or nailed down. Also, if the subfloor is a type that is susceptible to moisture damage (this includes

virtually all of the wood-based subfloor materials used in wood-frame construction), it should be protected by an impermeable

membrane placed between the finish flooring and the subfloor. The minimum degree of impermeability required by

Sentence 9.30.1.2.(1) would be provided by such materials as polyethylene, aluminum foil, and most single-ply roofing membranes

(EPDM, PVC).

width of insulated panel

groove widthgroove width

10 mm

∑groove width

insulated panel width

≥ 13%

EG01378A

10 mm

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.31.6.2.(3) Securement of Service Water Heaters.

Figure A-9.31.6.2.(3)

Securement of service water heater

Seismic Bracing of Hot Water Tank

“Guidelines for Earthquake Bracing of Residential Water Heaters” is available from the California Office of the State Architect

and provides more detail and alternate methods of bracing hot water tanks to resist earthquakes.

A-9.32.1.3.(2) Venting of Laundry-Drying Equipment. Sentence 9.32.1.3.(2) applies to the piping and ducting located

within the wall assembly and not to the often flexible duct used to connect the appliance to the rigid exhaust vent duct.

A-9.32.3. Heating-Season Mechanical Ventilation. While ventilation strategies can have a significant impact on energy

performance, ventilation is primarily a health and safety issue. Inadequate ventilation can lead to mold, high concentrations of CO2,

and other indoor air pollutants, which can lead to adverse health outcomes. Previous editions of the British Columbia Building Code

relied on ventilation through the building envelope in combination with a principal exhaust fan. However, with the increased

attention on the continuity of the air barrier system in buildings, builders can no longer rely on uncontrolled ventilation through the

building envelope. In most buildings, mechanical systems will be required to provide adequate ventilation for occupants.

As described in Article 9.32.3.3., every dwelling unit must include a principal ventilation system. A principal ventilation system is the

combination of an exhaust fan and a supply fan (or passive supply in some instances: see Sentence 9.32.3.4.(6)).

The principal ventilation system exhaust fan is separate from the requirements for a fan in every bathroom and kitchen. While a

bathroom fan may be used to satisfy both the requirements for the principal ventilation exhaust fan and the requirements for a

bathroom fan, the requirements for each must be met. If the fan provides this combined function of the principal ventilation exhaust

fan and the bathroom fan, it will also need to have controls that conform to Sentences 9.32.3.5.(3) and (4). Unlike other bathroom

fans, the principal ventilation exhaust fan is required to run continuously and should not have a control switch in a location where it

may be turned off inadvertently.

GC00383A

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.32.3.4. Principal Ventilation System Supply Air.

Figure A-9.32.3.4.(2)

Forced-Air Heating System Supply Air Distribution

Forced

air

heating

Furnace

cabinet

Supply

air

inlet

No less than 3.0 m*

and no greater than 4.5 m

(*unless a flow control

device is used)

Principal

ventilation system

exhaust fan

see table 9.32.3.5.

Furnace

air

return

Provide supply air

to each bedroom and

each floor level

without a bedroom

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.32.3.4.(3)

Forced-Air Heating System with Heat Recovery Ventilator Supply Air Distribution

At least 1

exhaust inlet

min. 2 m above

the floor

Furnace

air

return

Heat

recovery

ventilator

see table

9.32.3.5

Supply

air

inlet

Forced

air

heating

Furnace

cabinet

Provide supply air

to each bedroom and

each floor level

without a bedroom

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.32.3.4.(4)

Heat Recovery Ventilator Supply Air Distribution

Figure A-9.32.3.4.(5)(b)(i)

Central Recirculation System Supply Air Distribution

Supply

air

inlet

Provide supply air

to each bedroom and

each floor level

without a bedroom

Heat

recovery

ventilator

see table

9.32.3.5

At least 1

exhaust inlet

min. 2 m above

the floor

Air to a common area

Return air from

each bedroom

Used in addition to a

principal ventilation system

exhaust fan

Supply

air

inlet

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.32.3.4.(5)(b)(ii)

Central Recirculation System Supply Air Distribution

Figure 9.32.3.4.(6)

Passive Supply Air Distribution

A-9.32.3.4.(6)(a)(ii) Floor Area Calculation for Passive Supply Air Distribution. The floor area to be calculated for

Subclause 9.32.3.4.(6)(a)(ii) does not include sun porches, enclosed verandas, vestibules, attached garages, or other spaces that are

outside the building envelope and do not require ventilation supply air.

Air from

common

area

Supply

air

inlet

Supply air to

each bedroom

Used in addition to a

principal ventilation system

exhaust fan

Supply

air

inlet

Supply

air

inlet

Principal

ventilation system

exhaust fan -

see table 9.32.3.5.

At least

1800 mm

above the

floor

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.32.4.1. Naturally Aspirating Fuel-Fired Vented Appliance (NAFFVA). NAFFVA, typically appliances with draft

hoods, are subject to back drafting when a negative pressure condition occurs in the dwelling. The following tables describe the

conditions under which Sentence 9.32.4.1.(1) applies:

Table A-9.32.4.1.(1)-A

Vent Safety — Natural Gas and Propane

Fuel Type Natural Gas and Propane

Vent Type Power Vent

(3)

Direct Vent

(3)

Thermal Buoyancy Chimney

(2)

Appliance Type

Furnace

Boiler

HWT

Fireplace

HWT

Fireplace

Heater

Mid-Efficient F/A Furnace or

Boiler

(5)

Drafthood Boiler

HWT

(4)

Special Conditions Located in Air-Barriered

Room

(1)

Classification Non-NAFFVA NAFFVA Non-NAFFVA

9.32.4.1.(1)

Applies

No Yes No

Notes to Table A-9.32.4.1.(1)A.:

(1) Mechanical room must be air-barriered from remainder of house with no access from within house. Room must be lined with panel products with sealed joints and all pipe

and wire penetrations sealed. Effectively, the room must be finished before equipment is installed and holes drilled for pipes and wires. This option is not available for

forced air furnaces as it is not possible to effectively seal the ducts.

(2) Thermal buoyancy chimneys must be within the heated envelope of the house to provide acceptable venting performance.

(3) Any power vented appliance with pressurized vent (1 pipe) or sealed combustion (2 pipe) or direct vent appliance (fireplace, heater or HWT) are non-NAFFVA.

(4) Mid-efficient (draft induced) appliances are considered NAFFVA with the exception of a boiler or HWT located in an air-barriered room.

(5) This category applies only to

a) mid-efficient forced air furnaces equipped with induced draft fans and exhaust proving switch, and

b) boilers equipped with induced draft fans and exhaust proving switch.

Table A-9.32.4.1.(1)-B

Vent Safety — Oil and Solid Fuel

Fuel Type Oil Solid

Vent Type Thermal Buoyancy Chimney

(2)

Direct Vent Thermal Buoyancy Chimney

(2)

Any

Appliance Type

Boiler

HWT

(4)

F/A Furnace

Boiler

HWT

(3), (4)

F/A Furnace

Boiler

HWT

Boiler

F/A Furnace

Boiler

HWT

Fireplace

Heat Stove

Outside Boiler

Special Conditions Located in

Air-Barriered

Room

(1)

Located in

Air-Barriered

Room

(1)

Classification Non-NAFFVA NAFFVA Non-NAFFVA Non-NAFFVA NAFFVA(5) N/A

9.32.4.1.(1)

Applies

No Yes No No Yes(5) No

Notes to Table A-9.32.4.1.(1)B.:

(1) Mechanical room must be air-barriered from remainder of house with no access from within house. Room must be lined with panel products with sealed joints and all pipe

and wire penetrations sealed. Effectively, the room must be finished before equipment is installed and holes drilled for pipes and wires. This option is not available for

forced air furnaces as it is not possible to effectively seal the ducts.

(2) Thermal buoyancy chimneys must be within the heated envelope of the house to provide acceptable venting performance.

(3) Oil-fired HWT, boilers and furnaces equipped with blocked vent switches.

(4) Sealed combustion kits can be added to oil-fired appliances but they switch to interior combustion air if intake is blocked and rely on barometrically dampered thermal

buoyancy chimneys so they are considered NAFFVA.

(5) Wood-burning appliances certified for use in mobile homes and installed to mobile home installation standards are considered non-NAFFVA and Sentence 9.32.4.1.(1)

does not apply to them.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.32.4.2. Carbon Monoxide Alarms. Carbon monoxide (CO) is a colourless, odourless gas that can build up to lethal

concentrations in an enclosed space without the occupants being aware of it. Thus, where an enclosed space incorporates or is near a

potential source of CO, it is prudent to provide some means of detecting its presence.

Dwelling units have two common potential sources of CO:

• fuel-fired space- or water-heating equipment within the dwelling unit or in adjacent spaces within the building, and

• attached storage garages.

Most fuel-fired heating appliances do not normally produce CO and, even if they do, it is normally conveyed outside the building by

the appliance’s venting system. Nevertheless, appliances can malfunction and venting systems can fail. Therefore, the provision of

appropriately placed CO alarms in the dwelling unit is a relatively low-cost back-up safety measure.

Similarly, although Article 9.10.9.16. requires that the walls and floor/ceiling assemblies separating attached garages from dwelling

units incorporate an air barrier system, there have been several instances of CO from garages being drawn into houses, which indicates

that a fully gas-tight barrier is difficult to achieve. When the attached storage garage is located at or below the elevation of the living

space, winter season stack action will generate a continuous pressure between the garage and the dwelling unit. This pressure is capable

of transferring potentially contaminated air into the house. The use of exhaust fans in the dwelling unit may further increase this risk.

A-9.33.5.3. Design, Construction and Installation Standard for Solid-Fuel-Burning Appliances. CSA B365,

“Installation Code for Solid-Fuel-Burning Appliances and Equipment,” is essentially an installation standard, and covers such issues as

accessibility, air for combustion and ventilation, chimney and venting, mounting and floor protection, wall and ceiling clearances,

installation of ducts, pipes, thimbles and manifolds, and control and safety devices. But the standard also includes a requirement that

solid-fuel-burning appliances and equipment satisfy the requirements of one of a series of standards, depending on the appliance or

equipment, therefore also making it a design and construction standard. It is required that cooktops and ovens as well as stoves, central

furnaces and other space heaters be designed and built in conformity with the relevant referenced standard.

A-9.33.6.13. Return Air System. It is a common practice to introduce outdoor air to the house by means of an outdoor air

duct connected to the return air plenum of a forced air furnace. This is an effective method and is a component of one method of

satisfying the mechanical ventilation requirements of Subsection 9.32.3. However, some caution is required. If the proportion of cold

outside to warm return air is too high, the resulting mixed air temperature could lead to excessive condensation in the furnace heat

exchanger and possible premature failure of the heat exchanger. CAN/CSA-F326-M, “Residential Mechanical Ventilation Systems,”

requires that this mixed air temperature not be below 15.5°C when the outdoor temperature is at the January 2.5% value. It is also

important that the outdoor air and the return air mix thoroughly before reaching the heat exchanger. Note A-9.32.3. provides some

guidance on this.

A-9.33.10.2.(1) Factory-Built Chimneys. Under the provisions of Article 1.2.1.1. of Division A, certain solid-fuel-burning

appliances may be connected to factory-built chimneys other than those specified in Sentence 9.33.10.2.(1) if tests show that the use

of such a chimney will provide an equivalent level of safety.

A-9

.34.2. Lighting Outlets. The “Canadian Electrical Code, Part I” which is adopted by

the Electrical Safety Regulation,

contains requirements relating to lighting that are similar to those in the British Columbia Building Code. However, the Electrical

Code requirements apply only to residential occupancies, whereas many of the requirements in the British Columbia Building Code

apply to all Part 9 buildings. Code users must therefore be careful to ensure that all applicable provisions of the British Columbia

Building Code are followed, irrespective of the limitations in the Electrical Code.

A-9.35.2.2.(1) Garage Floor. Sources of ignition, such as electrical wiring and appliances, can set off an explosion if exposed

to gases or vapours such as those that can be released in garages. This provision applies where the frequency and concentration of such

releases are low. Where the garage can accommodate more than 3 vehicles, and where wiring is installed within 50 mm of the garage

floor, the “Canadian Electrical Code, Part I”, which is adopted by

the Electrical Safety Regulation, should be consulted as it specifies

more stringent criteria for wiring.

The capacity of the garage is based on standard-size passenger vehicles such as cars, mini-vans and sport utility vehicles, and half-ton

trucks. In a typical configuration, the capacity of the garage is defined by the width of the garage doors – generally single or double

width – which correlates to the number of parking bays.

In many constructions, floor areas adjacent to the garage are either above the garage floor level or separated from it by a foundation

wall. Where the foundation wall is cast-in-place concrete and rises at least 50 mm above the garage floor, it can serve as the airtight

curb. Where the foundation wall is block or preserved wood, extra measures may be needed to provide airtightness. In many instances,

the construction will be required to be airtight to conform with Sentence 9.25.3.1.(1), and in any case, must comply with

Sentences 9.10.9.16.(4) and (5).

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Where the space adjacent to the garage is at the same level as the garage, a 50 mm curb or partition is not needed if the wall complies

with Sentences 9.10.9.16.(4) and (5), and there is no connecting door. Where there is a connecting door, if the garage is not sloped

towards the exterior, it must be raised at least 50 mm off the floor or be installed so it closes against the curb. This requirement does

not preclude the installation of a ramp leading from the garage floor up to the door.

In some instances, access to the basement is via a stair from the garage. In such cases, a curb must be installed at the edge of the stair

well and must be sealed to the foundation wall, curb or partition between the garage and adjacent spaces.

See Figure A-9.35.2.2.(1).

Figure A-9.35.2.2.(1)

Curb around garage floor at stairs

GG00529A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.1.1.(1) Energy Used by the Building.

A-9.36.1.2.(2) Overall Thermal Transmittance. The U-value represents the amount of heat transferred through a unit area

in a unit of time induced under steady-state conditions by a unit temperature difference between the environments on its two faces.

The U-value reflects the capacity of all elements to transfer heat through the thickness of the assembly, as well as, for instance, through

air films on both faces of above-ground components. Where heat is not transferred homogeneously across the area being considered,

the thermal transmittance of each component is determined: for example, the thermal transmittance values of the glazing and the

frame of a window are combined to determine the overall thermal transmittance (U-value) of the window.

A-9.36.1.2.(3) Conversion of Metric Values to Imperial Values. To convert a metric RSI value to an imperial R-value,

use 1 (m

·K)/W = 5.678263 h · ft

· °F/Btu. “R-value,” or simply the prefix “R” (e.g. R20 insulation), is often used in the housing

industry to refer to the imperial equivalent of “RSI value.” Note that R-values in Section 9.36. are provided for information purposes

only; the stated metric RSI values are in fact the legally binding requirements.

A-9.36.1.2.(4) Fenestration. The term “fenestration” is intentionally used in Articles 9.36.2.3. (prescriptive provisions)

and 9.36.2.11. (trade-off provisions), and in Subsection 9.36.5. (performance provisions) as opposed to the terms “window,” “door”

and “skylight,” which are used in the prescriptive provisions in Subsections 9.36.2. to 9.36.4. that address these components

individually. The term “fenestration” is sometimes used in conjunction with the term “doors” depending on the context and the intent

of the requirement.

A-9.36.1.3. Compliance Options According to Building Type and Size. Table A-9.36.1.3. describes the types and

sizes of Part 9 buildings to which the various compliance paths within Section 9.36. apply.

Energy used by the building = space-heating energy lost and gained through building envelope

+ losses due to inefficiencies of heating equipment

+ energy necessary to heat outdoor air to ventilate the building

+ energy used to heat service water

Table A-9.36.1.3.

Energy Efficiency Compliance Options for Part 9 Buildings

Forming Part of Note A-9.36.1.3.

Building Types and Sizes

Energy Efficiency Compliance Options

9.36.2.

to 9.36.4.

(Prescriptive)

9.36.5.

(Performance)

9.36.6.

(Energy Step

Code)

NECB

• houses with or without a secondary suite

• buildings containing only dwelling units with common spaces ≤ 20% of building’s

total floor area

(1)

 

• buildings containing Group D, E or F3 occupancies whose combined total floor

area ≤ 300 m

(excluding parking garages that serve residential occupancies)

• buildings with a mix of Group C and Group D, E or F3 occupancies where the

non-residential portion’s combined total floor area ≤ 300 m

(excluding parking

garages that serve residential occupancies)



• buildings containing Group D, E or F3 occupancies whose combined total floor

area > 300 m

• buildings containing F2 occupancies of any size

XX X



Notes to Table A-9.36.1.3.:

(1) The walls that enclose a common space are excluded from the calculation of floor area of that common space.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.1.3.(3) Houses and Common Spaces.

Houses

For the purpose of Sentence 9.36.1.3.(3), the term “houses” includes detached houses, semi-detached houses, duplexes, triplexes,

townhouses, row houses and boarding houses.

Common spaces

The walls that enclose a common space are excluded from the calculation of floor area of that common space.

A-9.36.1.3.(5) Exemptions. Examples of buildings and spaces that are exempted from the requirements of Section 9.36.

include seasonally heated buildings, storage and parking garages, small service buildings or service rooms, unconditioned spaces in

buildings and unconditioned buildings such as storage warehouses. However, note that, where a building envelope assembly of an

exempted building is adjacent to a conditioned space, this assembly must meet the requirements of Section 9.36.

A-9.36.2.1.(2) Wall or Floor between a Garage and a Conditioned Space. A wall or a floor between a conditioned

space and a residential garage must be airtight and insulated because, even if the garage is equipped with space-heating equipment,

it may in fact be kept unheated most of the time.

A-9.36.2.2.(3) Calculation Tools. The thermal characteristics of windows, doors and skylights can be calculated using

software tools such as THERM and WINDOW.

A-9.36.2.2.(5) Calculating Effective Thermal Resistance of Log Walls. ICC 400, “Design and Construction of Log

Structures,” defines log wall thickness as the “average cross sectional area divided by the stack height.” This approach equalizes all log

profiles regardless of their size or shape by eliminating the need to vary, average or round out log thickness measurements, which

would otherwise be necessary to determine applicable profile factors for different log shapes. The ICC 400 standard lists R-values for

log walls, including the exterior and interior air film coefficients, based on wall thickness and wood species’ specific gravity.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.2.3.(2) and (3) Calculating Gross Wall Area. Where the structure of the lowest floor and rim joist assembly is

above the finished ground level or where the above-grade portion of foundation walls separates conditioned space from unconditioned

space, they should be included in the calculation of gross wall area. Figure A-9.36.2.3.(2) and (3) shows the intended measurements

for the most common type of housing construction.

Figure A-9.36.2.3.(2) and (3)

Example of interior wall height to be used in the calculation of gross wall area

wall height of side B

wall height of side A

end wall

average grade

EG00770A

finished ground level of side B

finished ground level of side A

If the wall height of side A = 5.7 m and the wall height of

side B = 6.7 m, then the end wall height = 6.2 m.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.2.3.(5) Areas of Other Fenestration. Figure A-9.36.2.3.(5) illustrates how to measure the area of glass panes as

described in Sentence 9.36.2.3.(5).

Figure A-9.36.2.3.(5)

Measuring the area of glazing that is not in the same plane

A-9.36.2.4.(1) Calculating the Effective Thermal Resistance of Building Envelope Assemblies. The general

theory of heat transfer is based on the concept of the thermal transmittance through an element over a given surface area under the

temperature difference across the element (see Sentence 9.36.1.2.(2)). As such, the NECB requires all building envelope assemblies

and components to comply with the maximum U-values (overall thermal transmittance) stated therein. However, the requirements in

Subsection 9.36.2. are stated in RSI values (effective thermal resistance values), which are the reciprocal of U-values.

To calculate effective thermal resistance, Section 9.36. requires that contributions from all portions of an assembly – including heat

flow through studs and insulation – be taken into account because the same insulation product (nominal insulation value) can produce

different effective thermal resistance values in different framing configurations. The resulting effective thermal resistance of an

assembly also depends on the thermal properties and thickness of the building materials used and their respective location.

The following paragraphs provide the calculations to determine the effective thermal resistance values for certain assemblies and the

thermal characteristics of common building materials. The Tables in Notes A-9.36.2.6.(1) and A-9.36.2.8.(1) confirm the compliance

of common building assemblies.

Calculating the Effective Thermal Resistance of an Assembly with Continuous Insulation:

Isothermal-Planes Method

To calculate the effective thermal resistance of a building envelope assembly containing only continuous materials – for example,

a fully insulated floor slab – simply add up the RSI values for each material. This procedure is described as the “isothermal-planes

method” in the “ASHRAE Handbook – Fundamentals.”

skylight

bow window

curved window

EG00733B

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Calculating the Effective Thermal Resistance of a Wood-frame Assembly: Isothermal-Planes and

Parallel-Path Flow Methods

To calculate the effective thermal resistance of a building envelope assembly containing wood framing, RSI

eff

, add up the results of

the following calculations:

A. calculate the effective thermal resistance of all layers with continuous materials using the isothermal-planes method, and

B. calculate the effective thermal resistance of the framing portion, RSI

parallel

, using the following equation, which is taken from

the parallel-path flow method described in the “ASHRAE Handbook – Fundamentals”:

where

RSI

= thermal resistance of the framing member obtained from Table A-9.36.2.4.(1)-D,

RSI

= thermal resistance of the cavity (usually filled with insulation) obtained from Table A-9.36.2.4.(1)-D,

% area of framing = value between 0 and 100 obtained from Table A-9.36.2.4.(1)-A or by calculation, and

% area of cavity = value between 0 and 100 obtained from Table A-9.36.2.4.(1)-A or by calculation.

When the values in Table A-9.36.2.4.(1)-D are used in the calculation of effective thermal resistance of assemblies, they must not

be rounded; only the final result, RSI

eff

, can be rounded to the nearest significant digit.

Example of Calculation of RSI

eff

for a Typical 38 × 140 mm Wood-frame Wall Assembly

Using the Isothermal-Planes and Parallel-Path Flow Methods

1. Determine the thermal resistance of each continuous material layer incorporated in the assembly using Table A-9.36.2.4.(1)-D

2. Calculate the thermal resistance of a section of framing and adjacent cavity portion, RSI

parallel

, using the parallel-path flow method as follows:

(i) along a line that goes through the framing, which is designated RSI

, and

(ii) along a line that goes through the cavity (usually filled with insulation), which is designated RSI

Look up the % area of framing and cavity for a typical 38 × 140 mm wood-frame wall assembly with studs 400 mm o.c. using Table A-9.36.2.4.(1)-A:

% area of framing = 23%, and

% area of cavity = 77%

Then, combine the sums of RSI

and RSI

in proportion to the relative areas of framing and insulation to calculate the value of RSI

parallel

(thermal resistance of the framing portion):

3. Add up the values obtained in steps 1 and 2 to determine the effective thermal resistance of the wall assembly, RSI

eff

38 x 140 mm wood

stud @ 406 mm o.c.

cavity insulation

EG00775A

23%

(area of

framing)

77%

(area of

cavity)

RSI

–

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Layers in 38 × 140 mm Wood-frame Wall Assembly with Studs Spaced 400 mm o.c.: RSI, (m²·K)/W

Outside air film 0.03

Metal siding 0.11

Sheathing paper –

Gypsum sheathing (12.7 mm) 0.08

Stud (140 mm × 0.0085 RSI/mm) RSI

= 1.19 % area of framing = 23% RSI

parallel

= 2.36

(U-value = 0.42 W/(m

·K))

Insulation (140 mm thick; RSI 3.34) RSI

= 3.34 % area of cavity = 77%

Polyethylene (vapour barrier) –

Gypsum (12.7 mm) 0.08

Interior air film 0.12

RSI

eff = 2.78 (m

·K)/W

(U-value = 0.36 W/(m

·K))

Table A-9.36.2.4.(1)-A

Framing and Cavity Percentages for Typical Wood-frame Assemblies

(1)

Wood-frame Assemblies

Frame Spacing, mm o.c.

304 406 488 610 1220

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

Floors lumber joists – – 13 87 11.5 88.5 10 90 – –

I-joists and

truss

– – 9917.592.5694– –

Roofs/

Ceilings

ceilings with

typical trusses

– – 14 86 12.5 87.5 11 89 – –

ceilings with

raised heel

trusses

– – 10 90 8.5 91.5 7 93 – –

roofs with

lumber rafters

and ceilings

with lumber

joists

– – 13 87 11.5 88.5 10 90 – –

roofs with I-joist

rafters and

ceilings with

I-joists

– – 9917.592.5694– –

roofs with

structural

insulated

panels (SIPs)

––––––––991

Example of Calculation of RSI

eff

for a Typical 38 × 140 mm Wood-frame Wall Assembly

Using the Isothermal-Planes and Parallel-Path Flow Methods

(continued)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

The framing percentage values listed in this Table for advanced framing are based on constructions with insulated lintels or framing

designed without lintels, corners with one or two studs, no cripple or jack studs, and double top plates.

Calculating the Effective Thermal Resistance of a Steel-frame Assembly

The parallel-path flow method described above for wood-frame assemblies involves simple one-dimensional heat ﬂow calculations

based on two assumptions:

• that the heat ﬂow through the thermal bridge (the stud) is parallel to the heat ﬂow through the insulation, and

• that the temperature at each plane is constant.

Tests performed on steel-frame walls have shown that neither of these assumptions properly represents the highly

two-dimensional heat ﬂow that actually occurs. The difference between what is assumed and what actually occurs is even more

significant in steel-frame assemblies. The results achieved using the calculation method below compare well with those achieved

from actual tests. The method provides a good approximation if a thermal resistance value of 0.0000161 (m

·K)/W per mm (or a

conductivity of 62 (W·m)/(m

·°C)) is used (this value is associated with galvanized steel with a carbon content of 0.14%).

To calculate the effective thermal resistance of a building envelope assembly consisting of steel framing, RSI

eff

, use the following

equation:

where

RSI

= effective thermal resistance of building envelope assembly determined using parallel-path flow method for

wood-frame assemblies (use framing and cavity percentages in Table A-9.36.2.4.(1)-C),

RSI

=RSI

+ thermal resistance values of all other components except steel studs and insulation,

where RSI

= effective thermal resistance of steel studs and insulation determined using parallel-path flow method for

wood-frame assemblies,

= applicable value from Table A-9.36.2.4.(1)-B, and

= applicable value from Table A-9.36.2.4.(1)-B.

Walls typical

wood-frame

24.5 75.5 23 77 21.5 78.5 20 80 – –

advanced

wood-frame

with double top

plate

(2)

– – 19 81 17.5 82.5 16 84 – –

SIPs ––––––––1486

basement

wood-frame

inside concrete

foundation wall

– – 16 84 14.5 85.5 13 87 – –

Notes to Table A-9.36.2.4.(1)-A:

(1) The framing percentages given in this Table account not just for the repetitive framing components but also for common framing practices, such as lintels, double top

plates, cripple studs, etc., and include an allowance for typical mixes of studs, lintels and plates. The values listed represent the percentage of wall area taken up by

framing and are based on the net wall area (i.e. gross wall area minus fenestration and door area). If the actual % areas of framing and cavity are known, those should be

used rather than the ones in this Table. Rim joists are not accounted for in this Table because they are addressed separately in Sentence 9.36.2.6.(2).

(2) “Advanced framing” refers to a variety of framing techniques designed to reduce the thermal bridging and therefore increase the energy efficiency of a building.

Some advanced framing solutions require that some framing components be insulated or eliminated; in such cases, it may be appropriate to calculate the actual % area

of framing. Note that using an advanced framing technique may require additional engineering of the framing system.

Table A-9.36.2.4.(1)-A (continued)

Framing and Cavity Percentages for Typical Wood-frame Assemblies

(1)

Wood-frame Assemblies

Frame Spacing, mm o.c.

304 406 488 610 1220

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

% Area

Framing

% Area

Cavity

RSI

e

= K



RSI

+ K



RSI

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Table A-9.36.2.4.(1)-B

Values for K

and K

Framing Spacing, mm K

< 500 without insulating sheathing 0.33 0.67

< 500 with insulating sheathing 0.40 0.60

≥ 500 0.50 0.50

Example of Calculation of RSI

eff

for a 41 × 152 mm Steel-frame Wall Assembly with Studs 406 mm o.c.

1. Calculate RSI

Materials in Assembly RSI

(thermal resistance

through framing)

RSI

(thermal resistance

through cavity)

Outside air film 0.03 0.03

Brick veneer 0.07 0.07

Air space (25 mm thick) 0.18 0.18

Extruded polystyrene (38 mm thick × RSI 0.035/mm) 1.33 1.33

Steel stud (152 mm thick × RSI 0.0000161/mm) 0.0023 –

Insulation (152 mm thick; RSI 3.52 (R20) batts) – 3.52

Polyethylene (vapour barrier) – –

Gypsum (12.7 mm thick) 0.08 0.08

Interior air film 0.12 0.12

Total 1.81 5.33

% area framing and cavity from Table A-9.36.2.4.(1)-C 0.77% 99.23%

(U-value = 0.19 W/(m

·K))

41 x 152 mm steel

stud @ 406 mm o.c.

brick veneer

insulating sheathing

cavity insulation

air/vapour barrier

12.7 mm

gypsum board

RSI

0.77%

(area of

framing)

99.23%

(area of

cavity)

EG00705A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

2. Calculate RSI

Materials in Assembly RSI

(thermal resistance

through framing)

RSI

(thermal resistance

through cavity)

Steel stud (152 mm thick × RSI 0.0000161/mm) 0.0023 –

Insulation (152 mm thick; RSI 3.52 (R20) batts) – 3.52

Total 0.0023 3.52

% area framing and cavity from Table A-9.36.2.4.(1)-C 0.77% 99.23%

(U-value = 3.69 W/(m

·K))

3. Calculate RSI

Materials in Assembly RSI through Assembly

Outside air film 0.03

Brick veneer 0.07

Air space (25 mm thick) 0.18

Extruded polystyrene (38 mm thick × RSI 0.035/mm) 1.33

RSI

0.27

Polyethylene (vapour barrier) –

Gypsum (12.7 mm thick) 0.08

Interior air film 0.12

RSI

= 2.08 (m

·K)/W

(U-value = 0.48 W/(m

·K))

4. Calculate RSI

eff

RSI

eff

= (K

· RSI

) + (K

· RSI

) = (0.40 · 5.25) + (0.60 · 2.08) = 3.35 (m

·K)/W (U-value = 0.30 W/(m

·K))

Table A-9.36.2.4.(1)-C

Framing and Cavity Percentages for Typical Steel-frame Assemblies

(1)

Steel-frame

Assemblies

Frame Spacing, mm o.c.

< 500 ≥ 500 < 2100 ≥ 2100

% Area

Framing

% Area Cavity

% Area

Framing

% Area Cavity

% Area

Framing

% Area Cavity

% Area

Framing

% Area Cavity

Roofs, ceilings,

floors

0.4399.570.3399.67––––

Above-grade walls

and strapping

0.7799.230.6799.33––––

Below-grade walls

and strapping

0.5799.430.3399.67––––

Sheet steel wall––––0.0899.920.0699.94

Notes to Table A-9.36.2.4.(1)-C:

(1) The framing percentages given in this Table are based on common framing practices and not simply on the width of the studs and cavity. They are based on 18-gauge

(1.2 mm) steel; however, test results indicate that, for the range of thicknesses normally used in light-steel framing, the actual thickness has very little effect on the

effective thermal resistance. If the actual % areas of framing and cavity are known, those should be used rather than the ones in this Table.

Example of Calculation of RSI

eff

for a 41 × 152 mm Steel-frame Wall Assembly with Studs 406 mm o.c. (continued)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Table A-9.36.2.4.(1)-D

Thermal Resistance Values of Common Building Materials

(1)

Air Films Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Exterior:

ceiling, floors and walls wind 6.7 m/s (winter) – – 0.03

Interior:

ceiling (heat flow up) – – 0.11

floor (heat flow down) – – 0.16

walls (heat flow horizontal) – – 0.12

Air Cavities

(2)(3)

Thickness of Air Space

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Ceiling (heat flow up) faced with non-reflective material

(4)

13 mm – 0.15

20 mm – 0.15

40 mm – 0.16

90 mm – 0.16

Floors (heat flow down) faced with non-reflective material

(4)

13 mm – 0.16

20 mm – 0.18

40 mm – 0.20

90 mm – 0.22

Walls (heat flow horizontal) faced with non-reflective material

(4)

9.5 mm – 0.15

13 mm – 0.16

20 mm – 0.18

40 mm – 0.18

90 mm – 0.18

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Cladding Materials Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Brick:

fired clay (2400 kg/m

) 100 mm 0.0007 0.07

concrete: sand and gravel, or stone (2400 kg/m

) 100 mm 0.0004 0.04

Cement/lime, mortar, and stucco – 0.0009 –

Wood shingles:

400 mm, 190 mm exposure – – 0.15

400 mm, 300 mm exposure (double exposure) – – 0.21

insulating backer board 8 mm – 0.25

Siding:

Metal or vinyl siding over sheathing:

hollow-backed – – 0.11

insulating-board-backed 9.5 mm nominal – 0.32

foiled-backed 9.5 mm nominal – 0.52

Wood:

bevel, 200 mm, lapped 13 mm – 0.14

bevel, 250 mm, lapped 20 mm – 0.18

drop, 200 mm 20 mm – 0.14

hardboard 11 mm – 0.12

plywood, lapped 9.5 mm – 0.10

Stone:

quartzitic and sandstone (2240 kg/m

)

– 0.0003 –

calcitic, dolomitic, limestone, marble, and granite (2240 kg/m

)

– 0.0004 –

Fibre-cement: single-faced, cellulose fibre-reinforced cement 6.35 mm 0.003 0.023

8 mm 0.003 0.026

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Roofing Materials

(5)

Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Asphalt roll roofing – – 0.03

Asphalt/tar – 0.0014 –

Built-up roofing 10 mm – 0.06

Crushed stone – 0.0006 –

Metal deck – – negligible

Shingle:

asphalt – – 0.08

wood – – 0.17

Slate 13 mm – 0.01

Sheathing Materials Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Gypsum sheathing 12.7 mm 0.0063 0.08

Insulating fibreboard – 0.016 –

Particleboard:

low density (593 kg/m

) – 0.0098 –

medium density (800 kg/m

) – 0.0077 –

high density (993 kg/m

) – 0.0059 –

Plywood – generic softwood 9.5 mm

0.0087

0.083

11 mm 0.096

12.5 mm 0.109

15.5 mm 0.135

18.5 mm 0.161

Plywood – Douglas fir 9.5 mm

0.0111

0.105

11 mm 0.122

12.5 mm 0.139

15.5 mm 0.172

18.5 mm 0.205

Sheet materials:

permeable felt – – 0.011

seal, 2 layers of mopped (0.73 kg/m

) – – 0.210

seal, plastic film – – negligible

Waferboard (705 kg/m

) – 0.0095 –

Oriented strandboard (OSB) 9.5 mm

0.0098

0.093

11 mm 0.108

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Insulation Materials

(6)

Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Blanket and batt: rock or glass mineral fibre (CAN/ULC-S702)

R12 89/92 mm – 2.11

R14 89/92 mm – 2.46

R19

(

(R20 compressed) 140 mm – 3.34

R20 152 mm – 3.52

R22 140/152 mm – 3.87

R22.5 152 mm – 3.96

R24 140/152 mm – 4.23

R28 178/216 mm – 4.93

R31 241 mm – 5.46

R35 267 mm – 6.16

R40 279/300 mm – 7.04

Boards and slabs:

Roof board – 0.018 –

Building board or ceiling tile, lay-in panel – 0.016 –

Polyisocyanurate/polyurethane-faced sheathing: Types 1, 2 and 3

(CAN/ULC-S704)

permeably faced 25 mm 0.03818 0.97

50 mm 0.0360 1.80

impermeably faced 25 mm 0.03937 1.00

50 mm 0.0374 1.87

Expanded polystyrene (CAN/ULC-S701)

(9)

Type 1 25 mm 0.026 0.65

Type 2 25 mm 0.028 0.71

Type 3 25 mm 0.030 0.76

Extruded polystyrene: Types 2, 3 and 4 (CAN/ULC-S701) 25 mm 0.035 0.88

50 mm 0.0336 1.68

Semi-rigid glass fibre wall/roof insulation (48 kg/m

) 25 mm 0.0298 0.757

Semi-rigid rock wool wall insulation (56 kg/m

) 25 mm 0.0277 0.704

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Insulation Materials

(8)

(continued) Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Loose-fill insulation

Cellulose (CAN/ULC-S703) – 0.025 –

Glass fibre loose fill insulation for attics (CAN/ULC-S702) 112 to 565 mm 0.01875 –

Glass fibre loose fill insulation for walls (CAN/ULC-S702) 89 mm 0.02865 2.55

140 mm 0.0289 4.05

152 mm 0.030 4.23

Perlite – 0.019 –

Vermiculite – 0.015 –

Spray-applied insulation

Sprayed polyurethane foam

medium density (CAN/ULC-S705.1) 25 mm 0.036 0.90

50 mm 0.036 1.80

light density (CAN/ULC-S712.1) 25 mm 0.026 0.65

Sprayed cellulosic fibre (CAN/ULC-S703) settled thickness 0.024 –

Spray-applied glass-fibre insulation (CAN/ULC-S702)

density: 16 kg/m

89 mm 0.025 2.30

140 mm 0.025 3.53

density: 28.8 kg/m

89 mm 0.029 2.64

140 mm 0.029 4.06

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Structural Materials Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Concrete

Low-density aggregate

expanded shale, clay, slate or slags, cinders (1 600 kg/m

)

– 0.0013 –

perlite, vermiculite, and polystyrene bead (480 kg/m

)

– 0.0063 –

Normal-density aggregate

sand and gravel or stone aggregate (2 400 kg/m

)

– 0.0004 –

Hardwood

(10)(11)

Ash – 0.0063 –

Birch – 0.0055 –

Maple – 0.0063 –

Oak – 0.0056 –

Softwood

(10)(11)

Amabilis fir – 0.0080 –

California redwood – 0.0089 –

Douglas fir-larch – 0.0069 –

Eastern white cedar – 0.0099 –

Eastern white pine – 0.0092 –

Hemlock-fir – 0.0084 –

Lodgepole pine – 0.0082 –

Red pine – 0.0077 –

Western hemlock – 0.0074 –

Western red cedar – 0.0102 –

White spruce – 0.0097 –

Yellow cyprus-cedar – 0.0077 –

Wood, structural framing, spruce-pine-fir

(12)

– 0.0085 –

Steel, galvanized sheet, 0.14% carbon content – 0.0000161 –

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Concrete Blocks Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Limestone aggregate with 2 cores

cores filled with perlite 190 mm – 0.37

290 mm – 0.65

Light-weight units (expanded shale, clay, slate or slag aggregate) with 2 or

3 cores

no insulation in cores 90 mm – 0.24

140 mm – 0.30

190 mm – 0.32

240 mm – 0.33

290 mm – 0.41

cores filled with perlite 140 mm – 0.74

190 mm – 0.99

290 mm – 1.35

cores filled with vermiculite 140 mm – 0.58

190 mm – 0.81

240 mm – 0.98

290 mm – 1.06

cores filled with molded EPS beads 190 mm – 0.85

molded EPS inserts in cores 190 mm – 0.62

Medium-weight units (combination of normal- and low-mass aggregate)

with 2 or 3 cores

no insulation in cores 190 mm – 0.26

cores filled with molded EPS beads 190 mm – 0.56

molded EPS inserts in cores 190 mm – 0.47

cores filled with perlite 190 mm – 0.53

cores filled with vermiculite 190 mm – 0.58

Normal-weight units (sand and gravel aggregate) with 2 or 3 cores

no insulation in cores 90 mm – 0.17

140 mm – 0.19

190 mm – 0.21

240 mm – 0.24

290 mm – 0.26

cores filled with perlite 190 mm – 0.35

cores filled with vermiculite 140 mm – 0.40

190 mm – 0.51

240 mm – 0.61

290 mm – 0.69

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Hollow Clay Bricks Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Multi-cored without insulation in cores 90 mm – 0.27

Rectangular 2-core

no insulation in cores 140 mm – 0.39

190 mm – 0.41

290 mm – 0.47

cores filled with vermiculite 140 mm – 0.65

190 mm – 0.86

290 mm – 1.29

Rectangular 3-core

no insulation in cores 90 mm – 0.35

140 mm – 0.38

190 mm – 0.41

240 mm – 0.43

290 mm – 0.45

cores filled with vermiculite 140 mm – 0.68

190 mm – 0.86

240 mm – 1.06

290 mm – 1.19

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Notes to Table A-9.36.2.4.(1)-D:

(1) The thermal resistance values given in Table A-9.36.2.4.(1)-D are generic values for the materials listed or minimum acceptable values taken from the standards listed.

Values published by manufacturers for their proprietary materials may differ slightly but are permitted to be used, provided they were obtained in accordance with the test

methods referenced in Article 9.36.2.2. For materials not listed in the Table or where the listed value does not reflect the thickness of the product, the thermal resistance

value has to be calculated by dividing the material’s thickness, in m, by its conductivity, in W/(m·K), which can be found in the manufacturer’s literature.

(2) RSI values can be interpolated for air cavity sizes that fall between 9.5 and 90 mm, and they can be moderately extrapolated for air cavities measuring more than 90 mm.

However, air cavities measuring less than 9.5 mm cannot be included in the calculation of effective thermal resistance of the assembly.

(3) Where strapping is installed, use the RSI value for an air layer of equivalent thickness.

(4) Reflective insulation material may contribute a thermal property value depending on its location and installation within an assembly. Where a value is obtained through

evaluation carried out in accordance with Clause 9.36.2.2.(4)(b), it may be included in the calculation of the thermal resistance or transmittance of the specific assembly.

(5) Materials installed towards the exterior of a vented air space in a roof assembly cannot be included in the calculation of effective thermal resistance of the assembly.

(6) All types of cellular foam plastic insulation manufactured to be able to retain a blowing agent, other than air, for a period longer than 180 days shall be tested for long-term

thermal resistance (LTTR) in accordance with CAN/ULC-S770, “Determination of Long-Term Thermal Resistance of Closed-Cell Thermal Insulating Foams.” This LTTR

value shall be input as the design thermal resistance value for the purpose of energy calculations in Section 9.36. Product standards contain a baseline LTTR for a thickness

of 50 mm, from which the LTTR for other thicknesses can be calculated.

(7) An RSI 3.52 (R20) batt compressed into a 140 mm cavity has a thermal resistance value of 3.34 (R19); if installed uncompressed in a 152 mm cavity (e.g. in a metal stud

assembly), it will retain its full thermal resistance value of 3.52 (m

·K)/W.

(8) All types of cellular foam plastic insulation manufactured to be able to retain a blowing agent, other than air, for a period longer than 180 days shall be tested for long-term

thermal resistance (LTTR) in accordance with CAN/ULC-S770, “Determination of Long-Term Thermal Resistance of Closed-Cell Thermal Insulating Foams.” This LTTR

value shall be input as the design thermal resistance value for the purpose of energy calculations in Section 9.36. Product standards contain a baseline LTTR for a thickness

of 50 mm, from which the LTTR for other thicknesses can be calculated.

Interior Finish Materials

(13)

Thickness of Material

Thermal Resistance

(RSI), (m

·K)/W per mm

Thermal Resistance

(RSI), (m

·K)/W for

thickness listed

Gypsum board – 0.0061 –

Hardboard – medium-density (800 kg/m

) – 0.0095 –

Interior finish (plank, tile) board – 0.0198 –

Particleboard

low-density (590 kg/m

) – 0.0098 –

medium-density (800 kg/m

) – 0.0074 –

high-density (1 000 kg/m

) – 0.0059 –

underlay 15.9 mm – 0.140

Plywood – 0.0087 –

Flooring material

Carpet and fibrous pad – – 0.370

Carpet and rubber pad – – 0.220

Cork tile 3.2 mm – 0.049

Hardwood flooring 19 mm – 0.120

Terrazzo 25 mm – 0.014

Tile (linoleum, vinyl, rubber) – – 0.009

Tile (ceramic) 9.5 mm – 0.005

Wood subfloor 19 mm – 0.170

Plastering

Cement plaster: sand aggregate – 0.0014 –

Gypsum plaster

low-density aggregate – 0.0044 –

sand aggregate – 0.0012 –

Table A-9.36.2.4.(1)-D (continued)

Thermal Resistance Values of Common Building Materials

(1)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

(9) Expanded polystyrene insulation is not manufactured to be able to retain a blowing agent; it is therefore not necessary to test its LTTR. See Note (8).

(10) The thermal resistance values for wood species are based on a moisture content (MC) of 12%. In Canada, equilibrium moisture content for wood in buildings ranges from

8-14%. The difference between the thermal properties of wood species with 12% MC and those with 14% MC is negligible.

(11) For wood species not listed in the Table, the RSI value of a wood species of equal or greater density (or specific gravity (relative density)) can be used since the thermal

resistance of wood is directly related to its density (higher density wood has a lower thermal resistance).

(12) 0.0085 is considered a common value for structural softwood (see also the “ASHRAE Handbook – Fundamentals”).

(13) Materials installed towards the interior of a conditioned air space cannot be included in the calculation of effective thermal resistance of the assembly.

A-9.36.2.4.(3) Calculating Thermal Resistance of Major Structural Penetrations. Projecting slabs contribute a

large area to the 2% exclusion so calculation and analysis of the heat loss through the area they penetrate should be carried out;

where construction features only occasional penetrations by beams or joists, the heat loss is less critical to the overall energy

performance of a building. Although the 2% exemption is based on gross wall area, it applies to penetrations through any building

envelope assembly.

A-9.36.2.4.(4) Credit for Unheated Spaces Protecting the Building Envelope. The reduction in RSI afforded by

Sentence 9.36.2.4.(4) is intended to provide a simple credit under the prescriptive path for any unheated space that protects a

component of the building envelope. The credited value is conservative because it cannot take into account the construction of the

enclosure surrounding the unheated space, which may or may not comply with the Code; as such, too many variables, such as its size

or airtightness, may negate any higher credit that could be allowed.

There may be simulation tools that can be used under the performance path to provide a better assessment of the effect of an indirectly

heated space; these tools may be used to calculate the credit more accurately when an unheated space is designed to provide

significantly better protection than the worst-case situation assumed here. Vented spaces, such as attic and roof spaces or crawl spaces,

are considered as exterior spaces; the RSI-value credit allowed in Sentence 9.36.2.4.(4) can therefore not be applied in the calculation

of the effective thermal resistance of assemblies separating conditioned spaces from vented spaces.

A-9.36.2.5.(1) Continuity of Insulation. Sentence 9.36.2.5.(1) is intended to apply to building components such as

partitions, chimneys, fireplaces, and columns and beams that are embedded along exterior walls, but not to stud framing and ends of

joists. Studs and joists in frame construction are not considered to break the continuity of the insulation because the method for

calculating the effective thermal resistance of such assemblies, which is described in Note A-9.36.2.4.(1), takes their presence into

consideration.

The rest of Article 9.36.2.5. contains exceptions to Sentence (1): Sentences (2) to (8) introduce relaxations for various construction

details while Sentence (9) allows a complete exemption to the requirements in Sentence (1) for three specific construction details.

Balcony and canopy slabs are also exempt from the requirements in Sentence (1) because their presence is permitted to be disregarded

when calculating the overall effective thermal resistance of walls they penetrate.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.2.5.(2) Thermal Bridging. Sentence 9.36.2.5.(2) aims to minimize thermal bridging within the building envelope,

which occurs when building elements conduct more heat than the insulated portion of the building envelope, which can lead to

significant heat loss through the thermal bridge. The most typical case to which Clause 9.36.2.5.(2)(a) applies is that of a firewall that

must completely penetrate the building envelope (see Figure A-9.36.2.5.(2)-A). Figures A-9.36.2.5.(2)-B and A-9.36.2.5.(2)-C

illustrate the insulation options presented in Clauses 9.36.2.5.(2)(b) and (c).

Figure A-9.36.2.5.(2)-A

Penetrating element insulated on both sides

Note to Figure A-9.36.2.5.(2)-A:

(1) See Article 3.1.10.7.

EG00769A

noncombustible material

(1)

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Figure A-9.36.2.5.(2)-B

Penetrating element insulated within exterior wall

Figure A-9.36.2.5.(2)-C

Penetrating element insulated within itself

Note to Figure A-9.36.2.5.(2)-C:

(1) See Article 9.10.11.2.

EG00767A

thermal resistance not less

than 60% of that required

for the penetrated element

EG00768A

no less than 12.7 mm

Type X gypsum board

(1)

insulation not shown

(additional insulation may

be required to achieve

fire-resistance rating)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.2.5.(3) Insulation of Masonry Fireplaces. The two insulation options for masonry fireplaces and flues presented in

Sentence 9.36.2.5.(3) are consistent with those presented in Sentences 9.36.2.5.(2) and (4) with the exception of the option to insulate

the sides of the penetrating element to 4 times the thickness of the penetrated wall, which would not be an energy-efficient option in

cases where the penetration by the fireplace or flue is several feet wide. Figures A-9.36.2.5.(3)-A and A-9.36.2.5.(3)-B illustrate the

options for achieving a continuously insulated exterior wall where it is penetrated by a masonry fireplace or flue.

Figure A-9.36.2.5.(3)-A

Masonry fireplace insulated within itself

Figure A-9.36.2.5.(3)-B

Masonry fireplace insulated within plane of insulation of exterior wall

RSI of insulation within fireplace = 55% of RSI of exterior wall

EG00781A

RSI of insulation behind fireplace = 55% of RSI of exterior wall

EG00782A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.2.5.(5) Maintaining Continuity of Insulation. An example to which Sentence 9.36.2.5.(5) does not apply is that of

a foundation wall that is insulated on the inside and the insulation continues through the joist cavity and into the wall assembly.

An example to which Sentence (5) does apply is a foundation wall that is insulated on the outside below grade and on the inside above

grade, in which case the distance separating the two planes of insulation is the thickness of the foundation wall.

In the configuration described in Sentence (5), the top of the foundation wall might also be required to be insulated to reduce the

effect of thermal bridging through it. Insulation is not required to be overlapped as stated in Sentence (5) in cases where the joist

cavities on top of the foundation wall are filled with insulation.

For cast-in-place concrete foundation walls, Sentence (5) ensures that the continuity of the insulation is maintained at every section

across the wall.

Figure A-9.36.2.5.(5)-A

Application of Sentence 9.36.2.5.(5) to a cast-in-place concrete foundation wall

EG00771A

insulation

4 x

cast-in-place

concrete

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

In the case of hollow-core masonry walls, the effect of convection in the cores needs to be addressed. The cores of the block course that

coincide with the respective lowest and highest ends of each plane of insulation should be filled with grout, mortar or insulation to

reduce convection within the cores, which could short-circuit the insulation’s function.

Figure A-9.36.2.5.(5)-B

Application of Sentence 9.36.2.5.(5) to a hollow-core masonry foundation wall

A-9.36.2.5.(6) Effective Thermal Resistance at Projected Area. Sentence 9.36.2.5.(6) does not apply to components

that completely penetrate the building envelope, such as air intake or exhaust ducts. However, it does apply to components that are

installed within or partially within the building envelope but that don’t penetrate to the outdoors, and to any piece of equipment that

is merely recessed into the wall.

A-9.36.2.5.(8) Effective Thermal Resistance at Joints in the Building Envelope. Sentence 9.36.2.5.(8) calls for

continuity of the effective thermal resistance at the junction between two components of the building envelope, such as a wall with

another wall, a wall with a roof, or a wall with a window. For example, where the gap is between a door frame (required U-value

1.8 = RSI value 0.56) and the rough framing members (required RSI value 2.93), it would have to be insulated to the RSI value of the

door as a minimum. However, completely filling the gap with insulation may not be necessary as this may in fact compromise the

rainscreen principle where required. Care should therefore be taken when installing insulation between windows, doors and walls.

EG00772A

insulation

4 x

solid

block

solid

block

fully solid units or hollow

or semi-solid units filled

with mortar or grout

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.2.6.(1) Thermal Characteristics of Above-ground Opaque Building Assemblies.

Building Envelope Insulation and Ventilation Options

Although the Code does not present any formal trade-off options between the building envelope requirements and the ventilation

or water-heating requirements, Tables 9.36.2.6.-A and 9.36.2.6.-B recognize that the same level of energy performance can be

achieved through two different combinations of building envelope insulation levels and different ventilation strategies.

The insulation values in Table 9.36.2.6.-A are based on mechanical ventilation solutions without heat recovery, while those in

Table 9.36.2.6.-B are based on a heat recovery ventilator (HRV) that operates for at least 8 hours a day throughout the year at the

minimum required ventilation capacity. The operation of the HRV affords a reduction in the RSI values for some assemblies,

most notably for walls and rim joists.

Nominal Insulation Values for Above-ground Walls

Tables A-9.36.2.6.(1)-A and A-9.36.2.6.(1)-B are provided to help Code users assess the compliance of above-ground walls with

Table 9.36.2.6.-A or 9.36.2.6.-B. Table A-9.36.2.6.(1)-A presents the minimum nominal thermal resistance to be made up in a

given wall assembly for it to achieve the applicable RSI value required by Table 9.36.2.6.-A or 9.36.2.6.-B. The amount of

additional materials needed to meet the prescribed RSI value can then be estimated using the thermal resistance values listed in

Table A-9.36.2.4.(1)-D for the rest of the building materials in the assembly, any finishing materials, sheathing or insulation,

if applicable, and the interior and exterior air films. See the example given in Note (4) of Table A-9.36.2.6.(1)-A.

Note that the wall assemblies described in Table A-9.36.2.6.(1)-A do not necessarily address other building envelope

requirements (see Section 9.25.).

Table A-9.36.2.6.(1)-A

Minimum Nominal Thermal Resistance (RSI) to be Made up by Insulation, Sheathing or Other Materials and

Air Films in Above-ground Wall Assemblies

Description of

Framing or

Material

Thermal Resistance of Insulated Assembly

Minimum Effective Thermal Resistance Required by Article 9.36.2.6. for

Above-ground Wall Assemblies, (m

·K)/W

Nominal,

·K)/W (ft

·°F·h/Btu)

Effective,

·K)/W

2.78 2.97 3.08 3.85

Insulation in

Framing Cavity

Continuous

Materials

Entire Assembly

Minimum Nominal Thermal Resistance,

(1)

in (m

·K)/W, to be Made up by

Insulation, Sheathing

(2)

or Other Materials and Air Film Coefficients

38 × 140 mm

wood at

406 mm o.c.

3.34 (R19)

(3)

None 2.36 0.42

(4)

0.61 0.72 1.49

1.32 (R7.5) 3.68 – – – 0.17

3.87 (R22) None 2.55 0.23 0.42 0.54 1.30

0.88 (R5) 3.43 – – – 0.42

4.23 (R24) None 2.66 0.12 0.30 0.42 1.18

38 × 140 mm

wood at

610 mm o.c.

3.34 (R19)

(3)

None 2.45 0.33 0.52 0.63 1.40

0.88 (R5) 3.33 – – – 0.52

1.32 (R7.5) 3.77 – – – 0.08

3.87 (R22) None 2.67 0.11 0.30 0.42 1.18

4.23 (R24) None 2.80 – 0.17 0.28 1.05

38 × 89 mm

wood at

406 mm o.c.

2.11 (R12) 0.88 (R5) 2.37 0.40 0.59 0.71 1.47

1.32 (R7.5) 2.81 – 0.15 0.27 1.03

1.76 (R10) 3.25 – – – 0.59

2.46 (R14) 0.88 (R5) 2.50 0.28 0.47 0.58 1.35

1.76 (R10) 3.38 – – – 0.47

38 × 89 mm

wood at

610 mm o.c.

2.11 (R12) 0.88 (R5) 2.43 0.35 0.54 0.65 1.42

1.32 (R7.5) 2.87 – 0.10 0.21 0.98

2.46 (R14) 1.76 (R10) 3.46 – – – 0.39

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Table A-9.36.2.6.(1)-B can be used to determine the total effective thermal resistance (RSI) value of the framing/cavity portion of a

number of typical above-ground wall assemblies as well as some atypical ones not covered in Table A-9.36.2.6.(1)-A. Additional

configurations and assembly types are listed in EnergyStar tables available online at

http://ENERGYSTARforNewHomesStandard.NRCan.gc.ca.

Select the applicable stud/joist size and spacing and the RSI/R-value of the insulation to obtain the resultant effective RSI value for that

frame configuration. If the RSI/R-value of the insulation product to be installed falls between two RSI/R-values listed in the Tab le,

the lower value must be used. Once the effective RSI value of the framing/cavity portion is known, add up the nominal RSI values of

all other materials in the assembly (see Table A-9.36.2.4.(1)-D) to obtain the total effective RSI value for the entire assembly. See the

calculation examples in Note A-9.36.2.4.(1) for further guidance.

Insulating

concrete form

(ICF), 150 mm

thick

(5)

n/a 3.52 (R20) 3.58 – – – 0.27

3.73 (R21.2) 3.79 – – – 0.06

Concrete block

masonry:

lightweight,

190 mm thick

n/a 1.76 (R10) 2.08 0.70 0.89 1.00 1.77

2.64 (R15) 2.96 – 0.01 0.12 0.89

3.52 (R20) 3.84 – – – 0.01

Concrete block

masonry:

normal-weight,

190 mm thick

n/a 1.76 (R10) 1.97 0.81 1.00 1.11 1.88

2.64 (R15) 2.85 – 0.12 0.23 1.00

3.52 (R20) 3.73 – – – 0.12

Notes to Table A-9.36.2.6.(1)-A:

(1) A dash (–) means that no additional materials are needed in order to meet the minimum required effective thermal resistance for the assembly in question; however,

sheathing may be required for fastening of cladding or lateral bracing.

(2) Where insulating sheathing is installed towards the exterior of the assembly, low permeance requirements addressed in Article 9.25.5.2. must be taken into consideration.

(3) When RSI 3.52 (R20) insulation batts are installed in 140 mm wood framing, they undergo some compression, which reduces their original RSI value to 3.34 (m

·K)/W

(R19). However, when they are installed in 152 mm metal framing, R20 batts retain their original thermal resistance value.

(4) Example: To determine what additional materials would be needed to make up 0.42 (m

·K)/W, the RSI values of the other components in the wall assembly are added up

as follows:

interior air film coefficient (walls): 0.12 (m

·K)/W

12.7 mm gypsum board interior finish: 0.08 (m

·K)/W

12.7 mm gypsum board exterior sheathing: 0.08 (m

·K)/W

metal or vinyl siding: 0.11 (m

·K)/W

exterior air film coefficient (walls): 0.03 (m

·K)/W

RSI of other components in assembly: 0.12 + 0.08 + 0.08 + 0.11 + 0.03 = 0.42 (m

·K)/W

Result: no additional materials are needed to meet the effective thermal resistance required for this particular wall assembly.

(5) There are many types of ICF designs with different form thicknesses and tie configurations. Where ICF systems incorporate metal ties, thermal bridging should be

accounted for. Where permanent wood blocking (bucks) for windows and doors is not covered by the same interior and exterior levels of insulation, it shall be accounted

for in the calculation of effective thermal resistance.

Table A-9.36.2.6.(1)-A (continued)

Minimum Nominal Thermal Resistance (RSI) to be Made up by Insulation, Sheathing or Other Materials and

Air Films in Above-ground Wall Assemblies

Description of

Framing or

Material

Thermal Resistance of Insulated Assembly

Minimum Effective Thermal Resistance Required by Article 9.36.2.6. for

Above-ground Wall Assemblies, (m

·K)/W

Nominal,

·K)/W (ft

·°F·h/Btu)

Effective,

·K)/W

2.78 2.97 3.08 3.85

Insulation in

Framing Cavity

Continuous

Materials

Entire Assembly

Minimum Nominal Thermal Resistance,

(1)

in (m

·K)/W, to be Made up by

Insulation, Sheathing

(2)

or Other Materials and Air Film Coefficients

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Table A-9.36.2.6.(1)-B

Effective Thermal Resistance (RSI) Values of the Framing/Cavity Portion of Above-Ground Wall Assemblies

Nominal Thermal Resistance

of Cavity Insulation

Size, mm, and Spacing, mm o.c., of Above-ground Wood-frame Wall Assembly

38 × 89 38 × 140

304 406 488 610 304 406 488 610

RSI, (m

·K)/W R, ft

·°F·h/Btu Effective Thermal Resistance of Framing/Cavity Portion,

(1)

·K)/W

1.94111.401.431.451.48––––

2.11121.471.491.521.55––––

2.29131.531.561.591.63––––

2.47 14 1.59 1.62 1.66 1.70 1.95 1.98 2.01 2.03

2.64 15 1.64 1.68 1.72 1.76 2.03 2.06 2.09 2.12

2.82 16 1.69 1.73 1.78 1.82 2.11 2.14 2.18 2.21

2.99 17 1.74 1.78 1.83 1.88 2.18 2.22 2.26 2.30

3.17 18 1.78 1.83 1.88 1.94 2.25 2.29 2.33 2.38

3.34 19 1.82 1.87 1.93 1.98 2.32 2.36 2.41 2.45

3.52 20 1.86 1.91 1.97 2.03 2.38 2.43 2.48 2.53

3.7021––––2.442.492.552.60

3.8722––––2.492.552.612.67

4.0523––––2.552.612.672.74

4.2324––––2.602.662.732.80

4.4025––––2.652.722.782.86

4.5826––––2.702.772.842.92

4.7627––––2.742.822.892.98

4.9328––––2.792.862.943.03

5.1129––––2.832.912.993.08

5.2830––––2.872.953.043.13

Notes to Table A-9.36.2.6.(1)-B:

(1) These RSI values are valid where the cavity is completely filled with insulation and they do not account for air space in the cavity. A dash (–) means that it is not feasible

to install the cavity insulation listed within the frame configuration in question.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.2.6.(3) Reduced Effective Thermal Resistance Near the Eaves of Sloped Roofs. Minimum thermal

resistance values for attic-type roofs are significantly higher than those for walls. The exemption in Sentence 9.36.2.6.(3) recognizes

that the effective thermal resistance of a ceiling below an attic near its perimeter will be affected by roof slope, truss design and required

ventilation of the attic space. It is assumed that the thickness of the insulation will be increased as the roof slope increases until there is

enough space to allow for the installation of the full thickness of insulation required.

Figure A-9.36.2.6.(3)

Area of ceiling assemblies in attics permitted to have reduced thermal resistance

A-9.36.2.7.(1) and (2) Design of Windows, Glazed Doors and Skylights. The design of windows, glazed doors and

skylights involves many variables that impact their energy performance and their compliance with the Code’s energy efficiency

requirements, such as the type of framing material, number of glass layers, type and position of low-emissivity (low-e) coating,

type and size of spacer between glass layers, type of gas used to fill the glass unit, and additionally for glazed doors, type of materials

used to construct the door slab.

Here are a few examples of common window and glazed door constructions:

• a U-value of about 1.8 is typically achieved using argon-filled glazing units with a low-e coating and energy-efficient spacer

materials installed in a frame chosen mostly for aesthetic reasons;

• a U-value of about 1.6 is typically achieved using triple glazing but may be achieved using double glazing with an optimized gas,

spacer and coating configuration installed in an insulated frame;

• a U-value of about 1.4 is typically achieved using triple glazing and multiple low-e coatings.

U-values and Energy Ratings (ER) for manufactured windows, glazed doors and skylights are obtained through testing in accordance

with the standards referenced in Sentence 9.36.2.2.(3). The U-value and/or ER number for a proprietary product that has been tested

can be found in the manufacturer’s literature or on a label affixed to the product.

A-Table 9.36.2.7.-A Thermal Characteristics of Windows and Doors. Energy Ratings, also known as ER numbers,

are based on CSA A440.2/A440.3, “Fenestration Energy Performance/User Guide to CSA A440.2-14, Fenestration Energy

Performance.”

They are derived from a formula that measures the overall performance of windows or doors based on solar heat gain, heat loss and air

leakage through frames, spacers and glass. The ER formula produces a single unitless ER number between 0 and 50 for each of the

specified sample sizes found in CSA A440.2/A440.3 (the number only applies to the product at the sample size and not to a particular

proprietary window or door). The higher the ER number, the more energy-efficient the product. Note that the ER formula does not

apply to sloped glazing so skylights do not have an ER value.

venting clearance

1200 mm maximum offset to reach full insulation value

= nominal RSI

≥ 3.52 (m²•K)/W (R20)

EG00776A

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

The maximum U-values specified in Table 9.36.2.7.-A are based on the following assumptions:

• that of moderate solar gain for each window and glazed door,

• that houses have a mix of picture and sash windows, each of which performs differently from an energy-efficiency perspective, and

• that fenestration area to gross wall area ratios typically vary between 8% and 25%.

A-9.36.2.7.(3) Site-built Windows. Site-built windows are often installed in custom-built homes or in unique configurations

for which manufactured units are not available. Article 9.7.4.1. requires windows, doors and skylights to conform to either the

standards referenced in Article 9.7.4.2. or to Part 5. Regardless of the compliance path chosen, the requirements of Section 9.7. and

9.36. must also be met. Windows, doors and skylights and other glazed products that comply with Part 5 and are installed in a Part 9

building may use the site-built provisions of Sentence 9.36.2.7.(3) rather than complying with the requirements in Sentence

9.36.2.7.(1).

A-9.36.2.8.(1) Nominal Insulation Values for Walls Below-Grade or in Contact with the Ground.

Tables A-9.36.2.8.(1)-A, A-9.36.2.8.(1)-B and A-9.36.2.8.(1)-C are provided to help Code users assess the compliance of walls that

are below-grade or in contact with the ground with Table 9.36.2.8.-A or 9.36.2.8.-B. Table A-9.36.2.8.(1)-A presents the minimum

nominal thermal resistance to be made up in a given wall assembly for it to achieve the applicable RSI value required by

Table 9.36.2.8.-A or 9.36.2.8.-B. The amount of additional materials needed to meet the prescribed RSI value can then be estimated

using the thermal resistance values listed in Table A-9.36.2.4.(1)-D for the rest of the building materials in the assembly, any finishing

materials, sheathing or insulation, if applicable, and the interior air film. For example, an RSI value of 0.20 (m

·K)/W needed to

achieve the minimum RSI for a given assembly could be made up by installing 12.7 mm gypsum board, which has an RSI value of

0.0775 (m

·K)/W, and by taking into account the air film coefficient on the interior side of the wall, which is 0.12 (m

·K)/W.

Note that the wall assemblies described in Table A-9.36.2.8.(1)-A do not necessarily address other structural or building envelope

requirements (see Section 9.25.).

Table A-9.36.2.8.(1)-A

Minimum Nominal Thermal Resistance (RSI) to be Made up by Insulation, Sheathing or Other

Materials and Air Films in Wall Assemblies Below-Grade or in Contact with the Ground

Description of

Framing or

Material

Size and

Spacing of

Wood Framing

Thermal Resistance of Insulated Assembly Minimum Effective Thermal Resistance Required by Article 9.36.2.8. for

Wall Assemblies Below-Grade or in Contact with the Ground, (m²·K)/W

Nominal,

·K)/W (ft

·°F·h/Btu)

Effective,

·K)/W 1.99 2.98 3.46 3.97

Insulation in

Framing Cavity

Continuous

Materials

Entire

Assembly

Minimum Nominal Thermal Resistance,

(1)

in (m

·K)/W, to be Made up by Insulation, Sheathing

(2)

or Other Materials and Air Film Coefficients

200 mm

cast-in-place

concrete

38 × 89 mm,

610 mm o.c.

2.11 (R12)

None 1.79 0.20 1.19 1.67 2.18

1.41 (R8) 3.20 – – 0.26 0.77

2.46 (R14) 1.76 (R10) 3.75 – – – 0.22

38 × 140 mm,

610 mm o.c.

3.34 (R19)

(3)

None 2.78 – 0.20 0.68 1.19

4.23 (R24) None 3.26 – – 0.20 0.71

None n/a

1.76 (R10) 1.84 0.15 1.14 1.62 2.13

2.64 (R15) 2.72 – 0.26 0.74 1.25

3.52 (R20)

(3)

3.60 – – – 0.37

190 mm

concrete block

masonry:

normal-weight,

no insulation in

cores

38 × 89 mm,

610 mm o.c.

2.11 (R12)

None 1.92 0.07 1.06 1.54 2.05

1.41 (R8) 3.33 – – 0.13 0.64

2.11 (R12) 4.03 – – – –

38 × 140 mm,

610 mm o.c.

3.34 (R19)

(3)

None 2.91 – 0.07 0.55 1.06

4.23 (R24) None 3.39 – – 0.07 0.58

None n/a

1.76 (R10) 1.97 0.02 1.01 1.49 2.00

2.64 (R15) 2.85 – 0.13 0.61 1.12

3.52 (R20)

(3)

3.73 – – – 0.24

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Tables A-9.36.2.8.(1)-B and A-9.36.2.8.(1)-C can be used to determine the total effective thermal resistance (RSI) value of the

framing/cavity portion of a number of typical below-grade wall assemblies as well as some atypical ones not covered in

Table A-9.36.2.8.(1)-A. Additional configurations and assembly types are listed in EnergyStar tables available online at

http://ENERGYSTARforNewHomesStandard.NRCan.gc.ca.

190 mm

concrete block

masonry:

light-weight, no

insulation in

cores

38 × 89 mm,

610 mm o.c.

2.11 (R12)

None 2.03 – 0.95 1.43 1.94

1.41 (R8) 3.44 – – 0.02 0.53

2.11 (R12) 4.14 – – – –

38 × 140 mm,

610 mm o.c.

3.34 (R19)

(3)

None 3.02 – – 0.44 0.95

4.23 (R24) None 3.50 – – – 0.47

None n/a

1.76 (R10) 2.08 – 0.90 1.38 1.89

2.64 (R15) 2.96 – 0.02 0.50 1.01

3.52 (R20) 3.84 – – – 0.13

Insulating

concrete form

(ICF):

(4)

150 mm

concrete

n/a n/a

3.52 (R20)

(3)

3.58 – – – 0.39

3.73 (R21.2) 3.79 – – – 0.18

Pressure-treat

ed wood frame

38 × 140 mm,

203 mm o.c.

3.34 (R19)

(3)

None 2.33 – 0.65 1.13 1.64

4.23 (R24) None 2.62 – 0.36 0.84 1.35

38 × 186 mm,

203 mm o.c.

4.93 (R28) None 2.81 – 0.17 0.65 1.16

38 × 235 mm,

203 mm o.c.

5.28 (R31) None 3.86 – – – 0.11

38 × 140 mm,

406 mm o.c.

3.34 (R19)

(3)

None 2.59 – 0.39 0.87 1.38

4.23 (R24) None 3.00 – – 0.46 0.97

38 × 186 mm,

406 mm o.c.

4.93 (R28) None 3.85 – – – 0.12

38 × 235 mm,

406 mm o.c.

5.28 (R31) None 4.11 – – – –

Notes to Table A-9.36.2.8.(1)-A:

(1) A dash (–) means that no additional materials are needed in order to meet the minimum required effective thermal resistance for the assembly in question; however,

sheathing may be required for fastening of cladding or lateral bracing.

(2) Wood-based sheathing ≥ 11 mm thick generally has a thermal resistance of 0.11 (m

·K)/W (R0.62). However, thicker sheathing may be required for structural stability or

fastening of cladding. Note that thinner R0.62 wood-based sheathing products are also available (see Table A-9.36.2.4.(1)-D).

(3) When RSI 3.52 (R20) insulation batts are installed in 140 mm wood framing, they undergo some compression, which reduces their original RSI value to 3.34 (m

·K)/W

(R19). However, when they are installed in 152 mm metal framing or in a wood frame that is offset from the back-up wall, R20 batts retain their original thermal

resistance value.

(4) There are many types of ICF designs with different form thicknesses and tie configurations. Where ICF systems incorporate metal ties, thermal bridging should be

accounted for.

Table A-9.36.2.8.(1)-A (continued)

Minimum Nominal Thermal Resistance (RSI) to be Made up by Insulation, Sheathing or Other

Materials and Air Films in Wall Assemblies Below-Grade or in Contact with the Ground

Description of

Framing or

Material

Size and

Spacing of

Wood Framing

Thermal Resistance of Insulated Assembly Minimum Effective Thermal Resistance Required by Article 9.36.2.8. for

Wall Assemblies Below-Grade or in Contact with the Ground, (m²·K)/W

Nominal,

·K)/W (ft

·°F·h/Btu)

Effective,

·K)/W 1.99 2.98 3.46 3.97

Insulation in

Framing Cavity

Continuous

Materials

Entire

Assembly

Minimum Nominal Thermal Resistance,

(1)

in (m

·K)/W, to be Made up by Insulation, Sheathing

(2)

or Other Materials and Air Film Coefficients

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Select the applicable stud/joist size and spacing and the RSI/R-value of the insulation to obtain the resultant effective RSI value for that

frame configuration. If the RSI/R-value of the insulation product to be installed falls between two RSI/R-values listed in the Ta bl e,

the lower value must be used. Once the effective RSI value of the framing/cavity portion is known, add up the nominal RSI values of

all other materials in the assembly (see Table A-9.36.2.4.(1)-D) to obtain the total effective RSI value of the entire assembly. See the

calculation examples in Note A-9.36.2.4.(1) for further guidance.

Table A-9.36.2.8.(1)-B

Effective Thermal Resistance (RSI) Values of the Framing/Cavity Portion of Pressure-treated Foundation Wall Assemblies

Nominal Thermal Resistance of

Cavity Insulation

Size, mm, and Spacing, mm o.c., of Pressure-treated Wood-frame Foundation Wall Assembly

38 × 185 38 × 235

203 304 406 203 304 406

RSI, (m

·K)/W R, ft

·°F·h/Btu Effective Thermal Resistance of Framing/Cavity Portion,

(1)

·K)/W

2.11 12 1.95 1.98 2.00 2.08 2.09 2.09

2.29 13 2.06 2.10 2.13 2.21 2.23 2.24

2.47 14 2.17 2.23 2.26 2.34 2.36 2.38

2.64 15 2.27 2.33 2.38 2.45 2.49 2.51

2.82 16 2.36 2.45 2.50 2.57 2.62 2.65

2.99 17 2.45 2.55 2.61 2.67 2.73 2.77

3.17 18 2.54 2.65 2.72 2.78 2.85 2.90

3.34 19 2.62 2.75 2.83 2.88 2.96 3.02

3.52 20 2.71 2.84 2.93 2.98 3.07 3.14

3.70 21 2.79 2.94 3.04 3.07 3.18 3.26

3.87 22 2.86 3.02 3.13 3.16 3.28 3.37

4.05 23 2.93 3.11 3.23 3.25 3.39 3.48

4.23 24 3.00 3.20 3.32 3.34 3.49 3.59

4.40 25 3.07 3.27 3.41 3.41 3.58 3.69

4.58 26 3.13 3.35 3.50 3.50 3.68 3.79

4.76 27 3.19 3.43 3.59 3.57 3.77 3.90

4.93 28 3.25 3.50 3.67 3.65 3.85 3.99

5.11 29 3.31 3.57 3.75 3.72 3.94 4.09

5.28 30 3.36 3.64 3.83 3.79 4.02 4.18

5.46 31 3.42 3.71 3.90 3.86 4.11 4.27

Notes to Table A-9.36.2.8.(1)-B:

(1) These RSI values are valid where the cavity is completely filled with insulation and they do not account for air space in the cavity.

Table A-9.36.2.8.(1)-C

Effective Thermal Resistance (RSI) Values of the Framing/Cavity Portion of

Below-Grade Interior Non-loadbearing Wood-frame Wall Assemblies

Nominal Thermal Resistance of

Cavity Insulation

Size, mm, and Spacing, mm o.c., of Below-Grade Interior Non-loadbearing Wood-frame Wall Assembly

38 × 89 38 × 140

203 304 406 610 203 304 406 610

RSI, (m

·K)/W R, ft

·°F·h/Btu Effective Thermal Resistance of Framing/Cavity Portion,

(1)

·K)/W

0.00 0 0.22 0.21 0.20 0.20 – – – –

1.41 8 1.17 1.21 1.24 1.27 – – – –

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-Tables 9.36.2.8.-A and -B Multiple Applicable Requirements. In cases where a single floor assembly is made up of

several types of the floor assemblies listed in Tables 9.36.2.8.-A and 9.36.2.8.-B, each portion of that floor must comply with its

respective applicable RSI value. For example, in the case of a walkout basement, the portion of floor that is above the frost line –

i.e. the walkout portion – should be insulated in accordance with the values listed in the applicable Table whereas the portion below

the frost line can remain uninsulated.

A-9.36.2.8.(2) Combination Floor Assemblies. An example of a floor assembly to which Sentence 9.36.2.8.(2) would

apply is a heated slab-on-grade with an integral footing.

1.94 11 1.41 1.50 1.55 1.61 – – – –

2.11 12 1.48 1.57 1.64 1.71 – – – –

2.29 13 1.54 1.65 1.73 1.81 – – – –

2.47 14 1.60 1.73 1.81 1.91 – – – –

2.64 15 1.65 1.79 1.89 1.99 – – – –

2.82 16 1.70 1.86 1.96 2.08 2.12 2.24 2.31 2.39

2.99 17 1.75 1.92 2.03 2.16 2.19 2.32 2.41 2.50

3.17 18 1.80 1.97 2.10 2.24 2.27 2.41 2.50 2.61

3.34 19 1.84 2.03 2.16 2.31 2.33 2.49 2.59 2.70

3.52 20 1.88 2.08 2.22 2.39 2.39 2.57 2.68 2.81

3.70 21 1.91 2.13 2.28 2.46 2.46 2.64 2.77 2.90

3.87 22 1.95 2.17 2.33 2.52 2.51 2.71 2.84 2.99

4.05 23 1.98 2.22 2.39 2.59 2.57 2.78 2.93 3.09

4.23 24 2.01 2.26 2.44 2.65 2.62 2.85 3.00 3.18

4.40 25 – – – – 2.67 2.91 3.07 3.26

4.58 26 – – – – 2.72 2.97 3.15 3.34

4.76 27 – – – – 2.77 3.03 3.22 3.42

4.93 28 – – – – 2.81 3.09 3.28 3.50

Notes to Table A-9.36.2.8.(1)-C:

(1) These RSI values are valid where the cavity is completely filled with insulation and they do not account for air space in the cavity. A dash (–) means that it is not feasible

to install the cavity insulation listed within the frame configuration in question.

Table A-9.36.2.8.(1)-C (continued)

Effective Thermal Resistance (RSI) Values of the Framing/Cavity Portion of

Below-Grade Interior Non-loadbearing Wood-frame Wall Assemblies

Nominal Thermal Resistance of

Cavity Insulation

Size, mm, and Spacing, mm o.c., of Below-Grade Interior Non-loadbearing Wood-frame Wall Assembly

38 × 89 38 × 140

203 304 406 610 203 304 406 610

RSI, (m

·K)/W R, ft

·°F·h/Btu Effective Thermal Resistance of Framing/Cavity Portion,

(1)

·K)/W

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.2.8.(4) Unheated Floors-on-ground Above the Frost Line. Figure A-9.36.2.8.(4) illustrates the insulation

options for unheated floors-on-ground that are above the frost line.

Figure A-9.36.2.8.(4)

Options for insulating unheated floors-on-ground

A-9.36.2.8.(9) Skirt Insulation. “Skirt insulation” refers to insulation installed on the exterior perimeter of the foundation and

extended outward horizontally or at a slope away from the foundation. In cold climates, skirt insulation is typically extended 600 to

1000 mm out from the vertical foundation wall over the footings to reduce heat loss from the house into the ground and to reduce the

chance of frost forming under the footings.

EG00737C

Clause 9.36.2.8.(4)(a)

Subclause 9.36.2.8.(4)(b)(ii)

Subclause 9.36.2.8.(4)(b)(iii)

Subclause 9.36.2.8.(4)(b)(i)

1.2 m

1.2 m or

to footing

1.2 m

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Figure A-9.36.2.8.(9)

Skirt insulation

A-9.36.2.9.(1) Controlling air leakage.

Airtightness Options

Sentence 9.36.2.9.(1) presents three options for achieving an airtight building envelope: one prescriptive option (Clause (a)) and

two testing options (Clauses (b) and (c)).

Air Barrier Assembly Testing

Air barrier assemblies are subjected to structural loading due to mechanical systems, wind pressure and stack effect. In addition,

they may be affected by physical degradation resulting from thermal and structural movement. Both CAN/ULC-S742, “Air

Barrier Assemblies – Specification,” and ASTM E 2357, “Determining Air Leakage of Air Barrier Assemblies,” outline testing

limits for such issues, which can compromise the performance of the air barrier assembly. Where local climatic data and building

conditions exceed these limits, the maximum building height and sustained 1-in-50 hourly wind pressure values covered in

Table 1 of CAN/ULC-S742 are permitted to be extrapolated beyond the listed ranges to apply to any building height, in any

location, provided the air barrier assembly in question has been tested to the specific building site and design parameters.

However, air barrier assemblies tested to ASTM E 2357 are not subjected to temperature variations during testing, and there is

no indication that testing data is permitted to be extrapolated beyond the 0.65 kPa limit.

Air Barrier System Approaches

For an air barrier system to be effective, all critical junctions and penetrations addressed in Articles 9.36.2.9. and 9.36.2.10. must

be sealed using either an interior or exterior air barrier approach or a combination of both.

The following are examples of typical materials and techniques used to construct an interior air barrier system:

• airtight-drywall approach

• sealed polyethylene approach

• joint sealant method

• rigid panel material (i.e. extruded polystyrene)

• spray-applied foams

• paint or parging on concrete masonry walls or cast-in-place concrete

Where the air barrier and vapour barrier functions are provided by the same layer, it must be installed toward the warm

(in winter) side of the assembly or, in the case of mass walls such as those made of cast-in place concrete, provide resistance to air

leakage through much of the thickness of the assembly. Where these functions are provided by separate elements, the vapour

barrier is required to be installed toward the interior of the assembly while the airtight element can be installed toward the interior

or exterior depending on its vapour permeance.

EG00777A

Insulation is extended 600 to 1000 mm

out from the foundation wall.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

The following are examples of typical materials and techniques used to construct an exterior air barrier system:

• rigid panel material (i.e. extruded polystyrene)

•house wraps

• peel-and-stick membranes

• liquid-applied membranes

When designing an exterior air barrier system, consideration should be given to the strength of the vapour barrier and expected

relative humidity levels as well as to the climatic conditions at the building’s location and the properties of adjoining materials.

A-9.36.2.9.(5) Making Fireplaces Airtight. Besides fireplace doors, other means to reduce air leakage through fireplaces are

available; for example, installing a glass-enclosed fireplace.

A-9.36.2.9.(6) Exterior Air Barrier Design Considerations. Any airtight assembly – whether interior or exterior – will

control air leakage for the purpose of energy efficiency. However, the materials selected and their location in the assembly can have

a significant impact on their effectiveness with regard to moisture control and the resistance to deterioration of the entire

building envelope.

A-9.36.2.10.(5)(b) Sealing the Air Barrier System with Sheathing Tape. One method of sealing air barrier materials

at joints and junctions is to apply sheathing tape that has an acceptable air leakage characteristic, is compatible with the air barrier

material and resistant to the mechanisms of deterioration to which the air barrier material will be exposed. Where an assembly tested to

CAN/ULC-S742, “Air Barrier Assemblies – Specification,” includes sheathing tape as a component, the sheathing tape will have been

tested for compatibility and resistance to deterioration and will be referenced in the manufacturer’s literature as acceptable for use with

that air barrier assembly.

A-9.36.2.10.(7)(a) Components Designed to Provide a Seal at Penetrations. An example of the component referred

to in Clause 9.36.2.10.(7)(a) is a plastic surround for electrical outlet boxes that has a flange to which sealant can be applied or that has

an integrated seal.

A-9.36.2.10.(9) Sealing the Air Barrier around Windows, Doors and Skylights. A continuous seal between

windows, doors and skylights and adjacent air barrier materials can be achieved by various means including applying exterior sealant,

interior sealant, low-expansion foam or sheathing tape in combination with drywall, polyethylene, a closed-cell backer rod, or a

wood liner.

A-9.36.2.10.(14) Sealing Duct Penetrations. Article 9.32.3.11. requires that joints in all ventilation system ducting be

sealed with mastic, metal foil duct tape or sealants specified by the manufacturer. Sentence 9.36.2.10.(14) requires that penetrations

made by ducts through ceilings or walls be sealed with appropriate sealant materials and techniques to prevent air leakage. Mechanical

fastening of the duct at the penetration may further reduce the likelihood of air leakage through the penetration.

A-9.36.2.11. Concept of Trade-offs. The trade-off options presented in Sentences 9.36.2.11.(2) to (4) afford some degree of

flexibility in the design and construction of energy-efficient features in houses and buildings as they allow a builder/designer to install

one or more assemblies with a lower RSI value than that required in Articles 9.36.2.1. to 9.36.2.7. as long as the discrepancy in

RSI value is made up by other assemblies and that the total area of the traded assemblies remains the same.

Limitations to Using Trade-off Options

In some cases, the energy-conserving impact of requirements cannot be easily quantified and allowing trade-offs would be

unenforceable: this is the case, for instance, for airtightness requirements (Article 9.36.2.10.). In other cases, no credit can be

given for improving energy performance where the Code permits reduced performance: for example, the Code allows insulation

to be reduced at the eaves under a sloped roof so no credit can be

given for installing raised heel trusses to accommodate the full

insulation value otherwise required by the Code; in other words, the increased RSI value that would be achieved with the raised

truss cannot be traded.

Furthermore, the trade-off calculations only address conductive heat loss through the building envelope and are therefore limited

in their effectiveness at keeping the calculated energy performance of a building in line with its actual energy performance,

which includes solar heat gains. The limitations stated in Sentence 9.36.2.11.(6) address this by ensuring that the thermal

resistances are relatively evenly distributed across all building assemblies.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

Terms Used in Trade-off Provisions

For the purposes of Article 9.36.2.11., the term “reference” (e.g. reference assembly) refers to a building element that complies

with the prescriptive requirements of Articles 9.36.2.1. to 9.36.2.7., whereas the term “proposed” refers to a building element

whose RSI value can be traded in accordance with Sentence 9.36.2.11.(2), (3) or (4), as applicable.

A-9.36.2.11.(2) Trading RSI Values of Above-Ground Opaque Building Envelope Assemblies.

Sentence 9.36.2.11.(2) applies where a designer wants to use a wall or ceiling assembly with a lower effective thermal resistance than

required by Subsection 9.36.2. in one building envelope area and an assembly with a compensating higher effective thermal resistance

in another building envelope area to achieve the same energy performance through the combined total areas as would be achieved by

complying with Subsection 9.36.2.

Example

A designer wants to reduce the insulation in 40 m

of wall area in the proposed design from the required effective RSI value of 3.27 (R24 batts in a

38 × 140 mm frame, 406 mm o.c.) to a value of 2.93 (R20 batts). The proposed design has 200 m

of attic space where more insulation could be added to

compensate for the lower RSI value in the 40 m

of wall.

Assemblies Being

Traded

Area of Each

Assembly (A)

Reference Design Values Proposed Design Values

RSI values (R) A/R Values RSI values (R) A/R Values

Attic 200 m

8.66 (m

·K)/W 23.09 W/K 8.66 (m

·K)/W 23.09 W/K

Wall 40 m

3.27 (m

·K)/W 12.23 W/K 2.93 (m

·K)/W 13.65 W/K

Total A/R value: 35.32 W/K Total A/R value: 36.74 W/K

The increased total A/R value for the attic and wall assemblies of the proposed design, which is caused by less insulation in the wall, now has to be

compensated for by an increase in attic insulation while keeping the respective areas of the building assemblies constant. To determine the RSI value to be

made up by insulation in the attic (i.e. increase in effective thermal resistance of attic assembly), first calculate the difference between the two total A/R

values:

36.74 W/K – 35.32 W/K = 1.42 W/K

Then, subtract this residual A/R value from the A/R value required for the attic insulation:

23.09 W/K – 1.42 W/K = 21.67 W/K

Adding this decreased A/R value for the proposed attic to the increased A/R value for the proposed wall now gives a total A/R value that is less than or equal

to that of the reference design:

21.67 W/K + 13.65 W/K = 35.32 W/K

To determine the RSI value to be made up by insulation in the attic of the proposed design, divide the area of the attic by the decreased A/R value required

for the attic of the proposed design (21.67 W/K):

200 m

/21.67 W/K = 9.23 (m

·K)/W (R52.4)

Assemblies Being

Traded

Area of Each

Assembly (A)

Reference Design Values Proposed Design Trade-off Values

RSI values (R) A/R Values RSI values (R) A/R Values

Attic 200 m

8.66 (m

·K)/W 23.09 W/K 9.23 (m

·K)/W 21.67 W/K

Wall 40 m

3.27 (m

·K)/W 12.23 W/K 2.93 (m

·K)/W 13.65 W/K

Total A/R value: 35.32 W/K Total A/R value: 35.32 W/K

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.2.11.(2) and (3) Calculating Trade-off Values. To trade effective thermal resistance values between above-ground

building envelope components or assemblies, the ratios of area and effective thermal resistance of all such components or assemblies for

the reference case (in which all components and assemblies comply with Article 9.36.2.6.) and the proposed case (in which the

effective thermal resistance values of some areas are traded) must be added up and compared using the following equation:

where

= effective thermal resistance of assembly i of the reference case,

= area of assembly i of the reference case,

= effective thermal resistance of assembly i of the proposed case,

= area of assembly i of the proposed case,

n = total number of above-ground components or assemblies, and

i = 1, 2, 3, …, n.

The sum of the areas of the above-ground assemblies being traded in the proposed case (A

) must remain the same as the sum of the

areas of the corresponding above-ground assemblies in the reference case (A

). Only the trade-off option described in

Sentence 9.36.2.11.(4) allows a credit for a reduction in window area where the window to gross wall area ratio is less than 17%.

A-9.36.2.11.(3) Trading R-values of Windows. Sentence 9.36.2.11.(3) applies where a designer wants to install one or

more windows having a U-value above the maximum permitted by Article 9.36.2.7. and reduce the U-value of other windows to

achieve the same overall energy performance through the combined total area of all windows as would be achieved by complying with

Article 9.36.2.7. (Note that R-values, not U-values as are typically used in relation to windows, are used in this Note.)

Example

A designer wants to install a large stained glass window on the south side of the proposed house as well as other windows for a total 12 m

in area.

The designer wants the stained glass window to have a U-value of 2.7 W/(m

·K) (R-value 0.37 (m

·K)/W), which is higher than the maximum permitted by

Subsection 9.7.3. for condensation resistance, and proposes to compensate for its reduced energy performance by reducing the U-value of the remaining

windows on that side, which total 10 m

Assemblies on South Side Total Area of Assemblies (A)

Reference Design Values

R-value (R) A/R Value

Windows 12 m

0.56 (m

·K)/W 21.54 W/K

Total A/R value: 21.54 W/K

Assemblies Being Traded

on South Side

Total Area of Assemblies (A)

Proposed Design Values

R-value (R) A/R Values

Stained glass window 2 m

0.37 (m

·K)/W 5.41 W/K

Other windows 10 m

0.56 (m

·K)/W 17.86 W/K

Total A/R value: 23.27 W/K

The increased total A/R value for the window assemblies on the south side of the proposed house, which is due to the stained glass window, now has to be

compensated for by better windows (i.e. with a lower U-value than the maximum allowed) while keeping the total area of windows in the house constant

(12 m

). To determine the R-value required to be made up by the rest of the windows on the south side, first calculate the difference between the two total

A/R values:

23.27 W/K – 21.54 W/K = 1.73 W/K

This value (1.73 W/K) now has to be subtracted from the A/R value for the 10 m

of windows to determine the compensating energy performance needed:

17.86 W/K – 1.73 W/K = 16.13 W/K

Adding this decreased A/R value for the windows to the increased A/R value for the stained glass window will now give a total A/R value that is less than or

equal to that of the reference design:

16.13 W/K + 5.41 W/K = 21.54 W/K

To determine the R-value to be made up by the rest of the windows on the south side of the proposed house, divide the area of the remaining windows by the

decreased A/R value for the 10 m

of windows:

10 m

/16.13 W/K = 0.62 (m

·K)/W (or a U-value of 1.6 W/(m

·K))

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.2.11.(4) RSI Values of Insulation in Attics under Sloped Roofs.

Trade-off Option for Buildings with Low Ceilings

The trade-off option presented in Sentence 9.36.2.11.(4) relating to buildings with a low floor-to-ceiling height and a relatively

low window and door area to wall area ratio recognizes the proven energy performance of single-section factory-constructed

buildings, which have very low sloped roofs in order to comply with transportation height limitations. This option is provided to

avoid unnecessarily imposing performance modeling costs. It is unlikely to be applied to site-constructed buildings or to

factory-constructed buildings that are not subject to stringent transportation height restrictions because low ceilings are not the

preferred choice, and the cost of cutting framing and interior finish panel products to size would exceed the cost of meeting the

prescriptive attic and floor insulation levels.

Trade-off Calculation

The trade-off option presented in Sentence 9.36.2.11.(4) allows the trading of a credit based on the difference between the

reference (prescriptive) and actual (proposed) window and door area. This credit can be used to reduce the required effective

thermal resistance of all ceiling or floor assemblies (attics).

where

i,c/f,r

= effective thermal resistance of ceiling/floor assembly i of the reference case,

i,c/f,r

= area of ceiling/floor assembly i of the reference case,

i,c/f,p

= effective thermal resistance of ceiling/floor assembly i of the proposed case,

i,c/f,p

= area of ceiling/floor assembly i of the proposed case,

w,r

(17%) = area of windows constituting 17% of gross wall area (see Article 9.36.2.3.),

w,r

= effective thermal resistance of windows (see Article 9.36.2.7.),

w,p

(max.15%) = area of windows constituting 15% or less of gross wall area (see Article 9.36.2.3.),

n = total number of ceiling/floor assemblies, and

i = 1, 2, 3,…, n.

The sum of A

i,c/f,p

must equal the sum of A

i,c/f,r

. The sum of the areas of all other building envelope assemblies must remain the

same in both the proposed and reference cases.

Assemblies Being Traded on

South Side

Total Area of Assemblies (A)

Proposed Design Trade-off Values

R-values (R) A/R Values

Stained glass window 2 m

0.37 (m

·K)/W 5.41 W/K

Other windows 10 m

0.62 (m

·K)/W 16.13 W/K

Total A/R value: 21.54 W/K

Example

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

Trading Window Area for Reduced Attic Insulation

Sentence 9.36.2.11.(4) applies where a proposed design has a fenestration and door area to gross wall area ratio (FDWR) of 15%

or less. The resulting reduction in energy loss due to the fact that there are fewer windows is traded for a reduction in R-value for

a specific area in the attic where it is impossible to install the required insulation level due to roof slope.

A-9.36.2.11.(6)(a) Reduction in Thermal Resistance of Ceilings in Buildings with Low Ceilings.

Sentence 9.36.2.11.(4) allows insulation in attics under sloped roofs to be reduced to less than the prescriptive level required for the

exterior walls, which may be less than 55% of the required values for the attic insulation.

A-9.36.3.2.(1) Load Calculations. Subsection 9.33.5. requires that heating systems serving single dwelling units be sized in

accordance with CSA F280, “Determining the Required Capacity of Residential Space Heating and Cooling Appliances.”

The HRAI Digest is also a useful source of information on the sizing of HVAC systems for residential buildings.

Example

A designer wants to use a FDWR of 12% in the proposed design in order to be able to install less insulation in the 100 m

of attic space.

Assemblies Being Traded Area of Each Assembly (A)

Reference Design Values (FDWR 17%)

RSI values (R) A/R Values

Attic 100 m

8.67 (m

·K)/W 11.5 W/K

Windows 25 m

0.63 (m

·K)/W 39.7 W/K

Total A/R value: 51.2 W/K

Assemblies Being Traded Area of Each Assembly (A)

Proposed Design Values (FDWR 12%)

RSI values (R) A/R Values

Attic 100 m

8.67 (m

·K)/W 11.5 W/K

Windows 18 m

0.63 (m

·K)/W 28.6 W/K

Total A/R value: 40.1 W/K

To determine the reduction in RSI value permitted for the attic insulation in the proposed design, first calculate the difference between the two A/R values:

51.2 W/K – 40.1 W/K = 11.1 W/K

This residual A/R value can now be used as a credit towards the A/R value of the attic insulation in the proposed design:

11.1 W/K + 11.5 W/K = 22.6 W/K

Adding this increased A/R value for the proposed attic to the A/R value for the proposed window area will now give a total A/R value that is less than or equal

to that of the reference design:

22.6 W/K + 28.6 W/K = 51.2 W/K

To determine the new RSI value of the attic insulation, divide the area of the attic by its new increased A/R value:

100 m

/22.6 W/K = 4.42 (m

·K)/W

Because Clause 9.36.2.11.(6)(b) limits the reduction of a traded RSI value for opaque building envelope assemblies – in this case, an attic – to 60% of the

minimum RSI value permitted by Article 9.36.2.6., this new RSI value of 4.42 (m

·K)/W for the attic is too low (60% × 8.67 = 5.20 (m

·K)/W). Therefore,

the full potential trade-off for this example cannot be used.

Assemblies Being Traded Area of Each Assembly (A)

Proposed Design Trade-off Values (FDWR 12%)

RSI values (R) A/R Values

Attic 100 m

5.20 (m

·K)/W 19.2 W/K

Windows 18 m

0.63 (m

·K)/W 28.6 W/K

Total A/R value: 47.8 W/K (< 51.2 W/K)

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.3.2.(2) Design and Installation of Ducts. The following publications contain useful information on this subject:

• the ASHRAE Handbooks

• the HRAI Digest

• the ANSI/SMACNA 006, “HVAC Duct Construction Standards – Metal and Flexible”

A-9.36.3.2.(5) Increasing the Insulation on Sides of Ducts. Table A-9.36.3.2.(5) can be used to determine the level of

insulation needed on the sides of ducts that are 127 mm deep to compensate for a reduced level of insulation on their underside.

A-9.36.3.3.(4) Exemption. The exemption in Sentence 9.36.3.3.(4) typically applies to heat-recovery ventilators and

ventilation systems that are designed to run or are capable of running continuously for specific applications. See also

Sentence 9.32.3.13.(8).

A-9.36.3.4.(1) Piping for Heating and Cooling Systems. CSA B214, “Installation Code for Hydronic Heating

Systems,” the ASHRAE Handbooks, the HRAI Digest, and publications of the Hydronics Institute are useful sources of information

on the design and installation of piping for heating and cooling systems.

A-9.36.3.4.(2) High-Temperature Refrigerant Piping. Piping for heat pumps is an example of high-temperature

refrigerant piping.

A-9.36.3.5.(1) Location of Heating and Air-conditioning Equipment. Locating certain types of equipment for heating

and air-conditioning systems – for example, heat-recovery ventilators or furnaces – outdoors or in an unconditioned space may result

in lower efficiencies and higher heat loss. Where components of a system are intended to be installed outside – for example, portions

of heat pump systems and wood-fired boilers – efficiency losses, if any, have already been accounted for in their design.

A-9.36.3.6.(7) Heat Pump Controls for Recovery from Setback. The requirements of Sentence 9.36.3.6.(7) can be

achieved through several methods:

• installation of a separate exterior temperature sensor,

• setting a gradual rise of the control point,

• installation of controls that “learn” when to start recovery based on stored data.

A-9.36.3.8. Application. Article 9.36.3.8. is intended to apply to any vessel containing open water in an indoor setting, not

only swimming pools and hot tubs; however, it does not apply to bathtubs. In the context of this Article, the terms “hot tub” and “spa”

are interchangeable.

Table A-9.36.3.2.(5)

RSI Required on Sides of Ducts where RSI on Underside is Reduced

RSI Required for

Exterior Walls,

(1)

·K)/W

RSI

(2)

on Underside

of 127 mm Deep

Duct, (m

·K)/W

Width of Duct, mm

304 356 406 457 483 508 533

RSI Required on Sides of Ducts, (m

·K)/W

2.78 2.11 4.47 4.98 5.61 6.43 6.94 n/a n/a

2.29 3.74 3.97 4.23 4.52 4.69 4.86 5.05

2.64 2.97 3.00 3.03 3.07 3.09 3.10 3.12

2.96 2.11 5.70 6.75 8.25 n/a n/a n/a n/a

2.29 4.56 5.02 5.58 6.27 6.68 n/a n/a

2.64 3.46 3.57 3.67 3.78 3.84 3.90 3.97

3.08 2.29 5.26 5.96 6.88 n/a n/a n/a n/a

2.64 3.85 4.02 4.20 4.40 4.50 4.62 4.73

3.85 3.43 4.67 4.84 5.03 5.23 5.34 5.45 5.56

Notes to Table A-9.36.3.2.(5):

(1) See Article 9.36.2.6.

(2) See Note A-9.36.1.2.(3) for the formula to convert metric RSI values to imperial R values.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.3.8.(4)(a) Heat Recovery from Dehumidification in Spaces with an Indoor Pool or Hot Tub.

Sentence 9.36.3.8.(4) is not intended to require that all air exhausted from a swimming pool or hot tub area pass through a

heat-recovery unit, only sufficient air to recover 40% of the total sensible heat. Most heat-recovery units can recover more than 40% of

the sensible heat from the exhausted air, but because it may not be cost-effective to reclaim heat from all exhaust systems, the overall

recovery requirement is set at 40%.

A-9.36.3.9.(1) Heat Recovery in Dwelling Units. Whereas Section 9.32. addresses the effectiveness of mechanical

ventilation systems in dwelling units from a health and safety perspective, Section 9.36. is concerned with their functioning from an

energy efficiency perspective.

The requirements of Subsection 9.32.3. can be met using one of several types of ventilation equipment, among them heat-recovery

ventilators (HRVs), which are typically the system of choice in cases where heat recovery from the exhaust component of the

ventilation system is required. As such, Article 9.36.3.9. should be read in conjunction with the provisions in Subsection 9.32.3. that

deal with HRVs.

A-9.36.3.9.(3) Efficiency of Heat-Recovery Ventilators (HRVs). HRVs are required to be tested in conformance with

CAN/CSA-C439, “Rating the Performance of Heat/Energy-Recovery Ventilators,” under different conditions to obtain a rating: to be

rated for colder locations, HRVs must be tested at two different temperatures, as stated in Clause 9.36.3.9.(3)(b), whereas their rating

for locations in mild climates relies only on the 0°C test temperature, as stated in Clause 9.36.3.9.(3)(a).

The performance of an HRV product and its compliance with Sentence 9.36.3.9.(3) can be verified using the sensible heat recovery at

the 0°C and/or –25°C test station (i.e. location where the temperature is measured) published in the manufacturer’s literature or in

product directories, such as HVI’s Certified Home Ventilating Products Directory.

The rating of HRVs also depends on the flow rate used during testing. Therefore, the minimum flow rate required in Section 9.32.

needs to be taken into consideration when selecting an HRV product.

A-9.36.3.10.(1) Unit and Packaged Equipment. The minimum performance values stated in Table 9.36.3.10. were

developed based on values and technologies found in the Model National Energy Code of Canada for Houses 1997, the NECB,

federal, provincial and territorial energy efficiency regulations as well as in applicable standards on equipment typically installed in

housing and small buildings.

In some cases – after a review of current industry practices (industry sales figures) – the performance requirements were increased from

regulated minimums where it could be shown that the cost and availability of the equipment are acceptable. Some of the performance

requirements are based on anticipated efficiency improvements in the energy efficiency regulations and revisions to standards.

A-9.36.3.10.(3) Multiple Component Manufacturers. Where components from more than one manufacturer are used as

parts of a heating, ventilating or air-conditioning system, the system should be designed in accordance with good practice using

component efficiency data provided by the component manufacturers to achieve the overall efficiency required by Article 9.36.3.10.

A-9.36.4.2.(1) Unit and Packaged Equipment. The minimum performance values stated in Table 9.36.4.2. were

developed based on values and technologies found in the Model National Energy Code of Canada for Houses 1997, the NECB,

federal, provincial and territorial energy efficiency regulations as well as in applicable standards on equipment typically installed in

housing and small buildings.

In some cases – after a review of current industry practices (industry sales figures) – the performance requirements were increased from

regulated minimums where it could be shown that the cost and availability of the equipment are acceptable.

A-9.36.4.2.(3) Exception. Components of solar hot

water systems and heat pump systems are examples of service water

heating equipment that is required to be installed outdoors.

A-9.36.4.6.(2) Required Operation of Pump. The water in indoor pools is pumped through filtration equipment at rates

that will help prevent the build-up of harmful bacteria and algae based on water volume and temperature, frequency of pool use,

number of swimmers, etc.

A-9.36.5.2. Use of Terms “Building” and “House”. Although the word “house” is used in the terms “proposed house”

and “reference house,” it is intended to include other types of residential buildings addressed by Subsection 9.36.5. The terms

“proposed building” and “reference building” used in the NECB apply to other types of buildings.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.5.3.(2) Concept of Comparing Performance. Comparing the performance of a reference house to that of a

proposed house is one way to benchmark the performance of a proposed house in relation to Code requirements. There are other ways

to benchmark energy consumption models: for example, by setting a quantitative energy target or using a benchmark design. In the

performance compliance option presented in Subsection 9.36.5., the user must demonstrate that their design results in a similar level

of performance to that of the prescriptive requirements – an approach that is consistent with the concept of objective-based codes.

Figure A-9.36.5.3.(2)

Energy consumption of proposed house versus that of reference house

A-9.36.5.4.(1) Calculation Procedure. It is important to characterize actual heat transfer pathways such as areas of

fenestration, walls, floors, ceilings, etc. An accurate geometric model of a house, including volume, captures such information,

but modeling can be carried out with other calculations.

Proposed House: complies with objectives of

Subsections 9.36.2. to 9.36.4. using

performance compliance option

Reference House: complies with prescriptive

requirements in Subsections 9.36.2. to 9.36.4.

≤ X

= X

EG00773A

X = calculated house energy target of reference house

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.5.4.(2) Space-Conditioning Load. Supplementary heating systems form part of the principal heating system and

must be able to meet the space-conditioning load of the house.

A-9.36.5.4.(7) Thermostatic Control. The thermostat’s response to temperature fluctuations described in

Sentence 9.36.5.4.(7) represents a thermostat deadband of ±0.5°C.

A-9.36.5.5.(1) Source of Climatic Data. Climatic data sources include the Canadian Weather Year for Energy Calculations

(CWEC) and the Canadian Weather Energy and Engineering Data Sets (CWEEDS). The CWEC represent average heating and

cooling degree-days which impact heating and cooling loads in buildings. The CWEC follow the ASHRAE WYEC2 format and were

derived from the CWEEDS of hourly weather information for Canada from the 1953-1995 period of record. The CWEC are

available from Environment Canada at http://climate.weatheroffice.gc.ca/prods_servs/index_e.html.

Where climatic data for a target location are not available, climatic data for a representative alternative location should be selected

based on the following considerations: same climatic zone, same geographic area or characteristics, heating degree-days (HDD) of the

alternative location are within 10% of the target location’s HDD, and the January 1% heating design criteria of the alternative location

is within 2°C of the target location’s same criteria (see Appendix C). Where several alternative locations are representative of the

climatic conditions at the target location, their proximity to the target location should also be a consideration.

A-9.36.5.6.(6) Contents of the House. In the context of Subsection 9.36.5., “contents of the house” refers to cabinets,

furniture and other elements that are not part of the building structure.

A-9.36.5.6.(11) Application. Sentence 9.36.5.6.(11) is not intended to apply to the fenestration area to wall area ratio.

A-9.36.5.7.(1) Consumption of HVAC systems. The energy consumption of HVAC systems typically includes the

distribution system and the effect of controls.

A-9.36.5.7.(5) Zoned Air Handlers. Zoned air handler systems may also have duct and piping losses.

A-9.36.5.8.(5) Water Delivery Temperature. A value of 55˚C is used in the energy model calculations; Article 2.2.10.7. of

Division B of the Book II (Plumbing Systems) of this Code contains different requirements relating to water delivery temperature.

A-9.36.5.9.(1) Modeling the Proposed House.

Completeness of the Energy Model Calculations

The specifications for a building typically include the following inputs and variables, among others, which are needed for

modeling:

• space-heating and domestic hot water (DHW) systems

• air-, ground- and water-source heat pumps

• central air-conditioning systems

• primary and secondary DHW systems

• efficiencies of heating and cooling equipment

• solar gain through windows facing each cardinal direction

• sloped glazing, including skylights

• overhangs, taking into account the hourly position of the sun with respect to each window and overhang on a typical day each

month

• the various levels of thermal mass

• slab-on-grade, crawl space (open, ventilated or closed), basement and walkout foundations, taking into account dimensions,

thermal resistance and placement of insulation, soil conductivity, depth of water table, and weather/climate, and

• heat transfer between the three zones of the house, i.e. the attic, main floor and foundation

Opaque Building Envelope Assemblies

In the context of Sentence 9.36.5.9.(1), the term “opaque building envelope assembly” includes above-ground assemblies and

those that are in contact with the ground.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.36.5.10.(2) Assembly Type. Sentence 9.36.5.10.(2) sets a limit on the size of building envelope assemblies that have to

be considered separately in the energy model calculations. In this context, assembly type is intended to mean either walls, roof,

fenestration, exposed floors, or foundation walls and is intended to include the respective assembly type areas of the entire building.

A-9.36.5.10.(9)(c)(ii) Equivalent Leakage Area (ELA). The ELA is the size of an imaginary hole through which the same

amount of air would pass that passes through all of the unintended openings in the building envelope if the pressure across all those

openings were equal. This value is needed in the calculation because it is a good indicator of the airtightness of the house: a leaky house

will have a large ELA and a very tight house will have a small ELA. For example, an energy-efficient house might have an ELA as low

as 200 cm

whereas a very leaky house can have an ELA of more than 3000 cm

A-9.36.5.10.(11) Timing of the Airtightness Test. The blower door test described in CAN/CGSB-149.10-M,

“Determination of the Airtightness of Building Envelopes by the Fan Depressurization Method,” should be carried out once the

building is substantially completed. Sufficient time should be allotted before completion to allow for subsequent air sealing in the

event the desired airtightness is not achieved. Interim testing while the air barrier is still accessible for service can also be helpful.

A-9.36.5.11.(9) Part-Load Performance of Equipment.

Measured Data

Where available, the measured part-load performance data are provided by the equipment manufacturer.

Modeled Part-Load Performance Data

Part-load performance ratings differ depending on the equipment. The intent of Sentence 9.36.5.11.(9) is to indicate that the

same modeled data source should be used for both the proposed and reference houses.

A-9.36.5.11.(10) Sensible Heat Recovery.

Treatment of Humidity in the Calculations

The calculations using sensible heat do not take latent heat (humidity) into account.

Energy-Recovery Ventilators

Energy-recovery ventilators can be used in lieu of heat-recovery ventilators.

A-9.36.5.11.(11) Circulation Fans. Sentences 9.36.5.11.(12) to (19) calculate the energy consumption of the circulation fan.

The results are intended to be used in energy model calculations only and are not intended to address the performance of the

ventilation system. The actual sizing of ventilation systems must comply with Section 9.32.

A-9.36.5.12.(2) Assumptions Relating to Drain-Water Heat Recovery. Energy savings associated with drain water

heat recovery depend on the duration of showers and the vertical drop in the drain pipe. Similar to the service water heating load

distribution, the length of showers depends on occupant behaviour. The values provided in Sentence 9.36.5.12.(2) are intended to be

used in the energy model calculations only and take into consideration the loads stated in Table 9.36.5.8. The efficiency of a

drain-water heat-recovery unit must be modeled using the same physical configuration intended for installation.

A-9.36.5.14.(10) Above-Ground Gross Wall Area. The determination of above-ground gross wall area is consistent with

the prescriptive requirements of Article 9.36.2.3. in that it is based on the measurement of the distance between interior grade and the

uppermost ceiling and on interior areas of insulated wall assemblies.

A-9.36.5.15.(5) Sizing of Heating and Cooling Systems. The intent of Sentence 9.36.5.15.(5) is that the cooling system

be sized only for the portion of the house that is cooled.

Article 9.33.5.1. references CSA F280, “Determining the Required Capacity of Residential Space Heating and Cooling Appliances,”

which contains a number of different methods for determining the capacity of heating appliances. The intent of

Sentence 9.36.5.15.(5) is that the equipment be sized according to the methods for total heat output capacity and nominal cooling

capacity without being oversized.

A-9.36.5.15.(6) Default Settings. The default settings in energy performance modeling software for houses are an appropriate

source of part-load performance values of equipment.

A-9.36.5.15.(8) Treatment of Humidity in the Calculations. The calculations using sensible heat do not take latent heat

(humidity) into account.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.36.6.2. Floor Area in the Energy Step Code. The words floor area, as used in Sentence 9.36.6.2.(1),

Sentence 9.36.6.2.(3), Sentence 9.36.6.3

.(1), Sentence 10.2.3.2.(1), and Sentence 10.2.3.2.(2) of Division B, and Sentence 2.2.8.3.(3)

of Division C are not italicized, to differentiate them from the defined term floor area in Article 1.4.1.2. of Division A.

Different modelling approaches identify the applicable floor area in various ways (e.g. modelled floor area, heated floor area, treated floor area,

etc.) and the use of the words floor area in Sentence 9.36.6.2.(1), Sentence 9.36.6.2.(3), Sentence 9.36.6.3

.(1), Sentence 10.2.3.2.(1), and

Sentence 10.2.3.2.(2) of Division B, and Sentence 2.2.8.3.(3) of Division C

is intended to accommodate the various modelling approaches.

A-9.36.6.2.(1)(f) Auxiliary HVAC Equipment. This category of equipment generally includes cooling tower fans,

humidifiers and other devices that do not directly fall under one of the other categories listed in Sentence 8.4.2.2.(1) of the NECB.

A-9.36.6.3.(2) Airtightness Testing for Step 1. Although there is no airtightness requirement for buildings conforming to

the requirements of Step 1, these buildings must still be tested in accordance with Article 9.36.6.5. and their air barriers must meet the

requirements of Subsection 9.25.3.

Buildings conforming to the requirements of Step 1 may also conform to Subsection 9.36.5. Although Sentence 9.36.5.10.(9)

provides the option of using the airtightness as tested in the energy modelling, using the result in the energy model is not required.

A-9.36.6.4.(2)(b) EnerGuide Rating System. Although not a requirement of the British Columbia Building Code, users of

the EnerGuide Rating System (ERS) must be energy advisors registered and in good standing with Natural Resources Canada in

accordance with the EnerGuide Rating System Administrative Procedures and must adhere to the technical standards and procedures

of the ERS. These standards and procedures are available through Natural Resources Canada and include program requirements for

energy modelling using the ERS.

A-9.36.6.4.(2)(c) NECB. Although the energy model calculation methods of the NECB are permitted to be used, the results of

those calculations must reflect the definitions and the requirements related to mechanical energy use intensity and

thermal energy

demand intensity as set out in Articles 9.36.6.2. and 9.36.6.3., and not the Annual Energy Consumption as required by Part 8 of

the NECB.

A-9.36.6.4.(4) Air Leakage Rate in Energy Model Calculations. For Step 1 buildings, airtightness testing must be

performed as required by Sentence 9.36.6.3.(2) and reported as required by Division C, but there is no minimum level of airtightness

required. See Sentence 9.36.5.10.(9) for requirements for the airtightness value to be used in the energy model calculations for Step 1

buildings using Subsection 9.36.5.

For buildings that must conform to the requirements of any of Steps 2 to 5, higher than expected air leakage may require the building

design to be altered and the energy model calculations to be repeated. Alternatively, the air leakage rate could be retested after making

alterations to the air barrier system to attain the desired air leakage rate.

A-9.37.1.1. Application. It is intended that Section 9.37. apply to the construction of a secondary suite, whether as an addition

to an existing building or as part of the construction of a new building. This Section may also be used as a standard for assessing an

existing additional dwelling unit located in a single family dwelling building (house), but is not intended to be applied as a retroactive

code to these existing units.

It is intended that the definition reflects that a secondary suite is an additional dwelling unit of limited size located within a house.

Many of the changes in Section 9.37. are premised on the condition of the limited size of the secondary suite, which may directly or

indirectly relate to issues such as occupant load, travel distance and egress dimensions.

In order for an additional dwelling unit to be considered a secondary suite, the following criteria must apply:

• There is only one secondary suite permitted in the building.

• It must be located in a building containing only residential occupancy.

• The secondary suite is located in or is part of a building containing only one other dwelling unit.

• The area of the secondary suite cannot exceed 90 m

of finished living area. (This does not include the areas used for common

storage, common laundry facilities or common areas used for egress.)

• The area of the secondary suite cannot exceed 40% of the total living floor space (area) of the building it is located in. (The living

floor area of the building does not include attached storage garages.)

• The secondary suite cannot be subdivided from the building it is part of under the Strata Property Act. This means that both

dwelling units are registered under the same title.

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.37.1.2. Construction Requirements. The requirements of Part 9 of the British Columbia Building Code apply to the

construction of a secondary suite and the alterations to a building to incorporate a secondary suite, except those specifically referenced

in Subsection 9.37.2.

A secondary suite may be constructed in a building that has been in existence for many years and that may not comply with current

code requirements. As it may not be feasible to comply with the current Code, discretion should be used provided it does not

substantially reduce the level of safety intended by the Code.

For example, existing stairs may not comply with current rise or run requirements; winders may not have the 150 mm tread at the

narrow end; guards may be a few millimeters lower than now required.

In some cases, existing sidelights or windows may not comply with the Code’s safety or security requirements. Acceptable safety

requirements can be achieved by applying decals, rails or safety films.

Insulation requirements may not comply with the current Code; window and door glazing may not be insulated or installed in

thermally broken frames.

Fire stops are required to be installed in new additions and in exposed existing locations, but it is not intended either that existing

finishes be removed to check for the presence of fire stops or that new fire stops be installed.

Doors required to have a 20 min fire-protection rating, or to be 45 mm solid core wood, may be mounted in existing door frames that

are less than 38 mm in thickness if it would require substantial framing alterations to accommodate a 38 mm thick frame.

It is not the intent to retroactively apply the current Code to all existing features in order to permit the construction of a secondary

suite in an existing building.

A-9.37.2.3.(1) Exit Stairs. Existing internal and external stairs that formerly served one dwelling unit may now serve both the

existing dwelling unit and the new secondary suite. It is not the intent to apply all current Code exit stair requirements in order to

permit the construction of a secondary suite in an existing building.

A-9.37.2.6. Means of Egress. The additional occupant load created by a secondary suite does not warrant increasing the

width of a public corridor, common exit stair or landing used by both dwelling units. The stairs, corridors and landings formerly

serving one dwelling unit are likely to be of adequate size to accommodate the occupant load of both suites.

A-9.37.2.8. Openings Near Unenclosed Exit Stairs and Ramps. Unprotected door or window openings in other fire

compartments adjacent to exit stairs and ramps should be protected from the other suite to provide safe passage to a safe area.

Normally such protection as required by Part 9 would extend both vertically and horizontally beyond the adjacent openings. This is

considered excessive due to required fire safety measures and the relatively short travel distances in this type of building.

The application of current Part 9 requirements would in many cases require the protection of all openings in entire faces of dwelling

units, which could be very restrictive. Authorities should exercise judgment with regard to deciding which openings are close enough

to the exit facility to pose a problem during the early stages of a fire and require appropriate opening protection. Those openings that

directly pass the means of egress are required to be protected.

Effective December 10, 2018 to December 11, 2019

Notes to Part 9 – Housing and Small Buildings Division B: Acceptable Solutions

Division B

British Columbia Building Code 2018

A-9.37.2.14. Combustible Drain, Waste and Vent Piping. Exposed combustible drain, waste and vent piping that

penetrates a fire separation is required to be protected as described. This protection is not required for exposed fixture traps and arms

serving fixtures within the suite provided they are not exposed from the underside of a horizontal fire separation. The intent is not to

require removal of existing combustible piping which, as a result of the creation of a secondary suite, may now be on both sides of a

rated fire separation. Rather, the intent is to protect this piping where it is exposed.

Figure A-9.37.2.14.

Combustible Drain, Waste and Vent Pipe

A-9.37.2.15. and 16. Separation of Residential Suites and Public Corridors. Two options are permitted for the

separation of residential suites required by Article 9.10.9.14. and the separation of suites and public corridors required by

Article 9.10.9.15.

One option is to separate the suites with a fire separation having a fire-resistance rating of 30 min and provide in each suite an

additional smoke alarm interconnected with the smoke alarm in the other suite (described in Article 9.37.2.19.). A 30 min

fire-resistance rating can be achieved with 12.7 mm Type X gypsum board on framing 400 mm o.c. for vertical assemblies, and 12.7

mm Type X or 15.9 mm gypsum board on frame floor/ceiling assemblies. This is often typical construction in modern single dwelling

houses. This option will provide an equivalent level of life safety as the occupants of the building will be made aware of the hazard by

an automatic detection system in the early stages, allowing them early evacuation.

The second option is to provide an automatic sprinkler system conforming to an NFPA standard throughout the building (i.e. both

suites and common areas). With this provision, no fire-resistance rating is required, but the suites must still be separated by a fire

separation. Automatic sprinkler systems are a recognized alternative to fire-resistance ratings as a sprinkler system should control the

fire at its early stage, preventing its propagation.

A-9.37.2.17. Air Ducts and Fire Dampers. In order to prevent the migration of smoke from one suite to another during a

fire, heating or ventilation systems incorporating ducts that serve both suites are permitted only if there is a mechanism to prevent

smoke being circulated from one unit to the other. It is preferable for the secondary suite to have its own heating system independent

of the rest of the building.

Unit 'A'

Rated

Fire

Separations

Opening Sealed or

Limited to Size of Pipe

Unrated

Partition

Unit 'A'

Unit 'B'

(Secondary Suite)

NOT

PERMITTED

Combustible

DWV Pipe

Minimum

12.7

gypsum

wallboard

Effective December 10, 2018 to December 11, 2019

Division B: Acceptable Solutions Notes to Part 9 – Housing and Small Buildings

British Columbia Building Code 2018 Division B

A-9.37.2.19. Smoke Alarms. This Article requires an interconnected photoelectric smoke alarm in each suite where fire

separations having a fire-resistance rating of 30 min are used. The purpose of these interconnected alarms is to provide early warning to

both suites in the event of a fire in one suite. Photoelectric type alarms are required as they are less prone to nuisance false alarms such

as can occur during cooking, but careful consideration is still required as to their location.

It is important to note that these alarms are additional to the requirements of Subsection 9.10.19. and that each suite is still required

to be provided with alarms in conformance with Subsection 9.10.19.

The additional smoke alarm should not be interconnected to the other smoke alarm(s) located within the same suite.

This additional smoke alarm system is not required when the fire-resistance ratings required in Articles 9.10.9.14. and 9.10.9.15. are

not reduced, or when the building is sprinklered.

A-9.37.2.20. Sound Control. Meeting the Code’s level of sound transmission for secondary suites may be difficult and

expensive, particularly in an existing building. As there is single ownership of both dwelling units, this requirement is not mandatory,

but designers are encouraged to take the subject into consideration where feasible.