The British Columbia Building Code | Section 9.2. | Definitions
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.2. Definitions
9.2.1. General
9.2.1.1. Defined Words
1) Words in italics are defined in Article 1.4.1.2.of Division A.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.20. Masonry and Insulating Concrete Form Walls
Not In Contact with the Ground
9.20.1. Application
9.20.1.1. General
1) Except as provided in Article9.20.1.2., this Section applies to
a) unreinforced masonry and masonry veneer walls not in contact with the ground, where
i) the height of the walls constructed on the foundation walls does not exceed 11m, and
ii) the roof or floor assembly above the first storey is not of concrete construction, and
b) flat insulating concrete form walls not in contact with the ground that (seeNoteA-9.15.1.1.(1)(c) and
9.20.1.1.(1)(b))
i) have a maximum floor-to-floor height of 3m,
ii) are erected in buildings not more than 2 storeys in building height and containing only a single dwelling
unit, and
iii) are erected in locations where the seismic spectral response acceleration, S
a
(0.2), is not greater than 0.4
(seeNoteA-9.20.1.2.).
2) For walls other than those described in Sentence(1), or where the masonry walls or insulating concrete form
walls not in contact with the ground are designed for specified loads on the basis of ultimate and serviceability limit
states, Subsection4.3.2. shall apply.
9.20.1.2. Earthquake Reinforcement
(SeeNoteA-9.20.1.2.)
1) In locations where the spectral response acceleration, S
a
(0.2), is greater than 0.55, loadbearing elements of
masonry buildings more than 1 storey in building height shall be reinforced with not less than the minimum amount of
reinforcement required by Subsection9.20.15.
2) In locations where the spectral response acceleration, S
a
(0.2), is greater than 0.35 but less than or equal to
0.55, loadbearing elements of masonry buildings 3 storeys in building height shall be reinforced with not less than the
minimum amount of reinforcement required by Subsection9.20.15.
9.20.2. Masonry Units
9.20.2.1. Masonry Unit Standards
1) Masonry units shall comply with
a) ASTM C 73, “Calcium Silicate Brick (Sand-Lime Brick),”
b) ASTM C 126, “Ceramic Glazed Structural Clay Facing Tile, Facing Brick, and Solid Masonry Units,”
c) ASTM C 212, “Structural Clay Facing Tile,”
d) CAN/CSA-A82, “Fired Masonry Brick Made from Clay or Shale,”
e) CSAA165.1, “Concrete Block Masonry Units,”
f) CSAA165.2, “Concrete Brick Masonry Units,” or
g) CSAA165.3, “Prefaced Concrete Masonry Units.”
9.20.2.2. Used Brick
1) Used bricks shall be free of old mortar, soot or other surface coating and shall conform to Article9.20.2.1.
9.20.2.3. Glass Blocks
1) Glass blocks shall not be used as loadbearing units or in the construction of fireplaces or chimneys.
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Division B
9.20.2.4. Cellular Concrete
1) Masonry made with cellular concrete shall not be used in contact with the soil or exposed to the weather.
9.20.2.5. Stone
1) Stone shall be sound and resistant to deterioration.
9.20.2.6. Concrete Blocks Exposed to the Weather
1) Concrete blocks exposed to the weather shall have density and water absorption characteristics conforming to
concrete typesA, B, C, or D described in CSAA165.1, “Concrete Block Masonry Units.”
9.20.2.7. Compressive Strength
1) The compressive strength of concrete blocks shall conform to Table9.20.2.7.
9.20.3. Mortar and Grout
9.20.3.1. Materials
1) Cementitious materials and aggregates for mortar and grout shall comply with CSAA179, “Mortar and
Grout for Unit Masonry.”
2) Water and aggregate shall be clean and free of significant amounts of deleterious materials.
3) Lime used in mortar shall be hydrated.
4) If lime putty is used in mortar, it shall be made by slaking quicklime in water for not less than 24h or soaking
hydrated lime in water for not less than 12h.
9.20.3.2. Mortar and Grout Mixes
1) Mortar types shall be in accordance with Table9.20.3.2.-A.
2) Mortar for glass block masonry shall be
a) TypeS Portland cement-lime where exposed to the exterior, or
b) TypeS or N where protected from the exterior.
3) Mortar shall be mixed within the proportion limits provided in Table9.20.3.2.-B, with sufficient water to
bring the mixture to a consistency adequate for laying masonry units.
4) Grout shall be mixed within the proportion limits provided in Table9.20.3.2.-C, with sufficient water to
provide a suitable flow to fill all voids completely, without excessive segregation or bleeding.
5) Except as provided in Sentence(6), mortar shall be used and placed in final position
a) within 1.5h after mixing when the air temperature is 25°C or higher, or
b) within 2.5h after mixing when the air temperature is less than 25°C.
6) Mortar and grout containing a set-control admixture shall be manufactured off-site in a batching plant and
shall be used and placed in final position within a time not exceeding the useful life stipulated by the manufacturer.
Table 9.20.2.7.
Compressive Strength of Concrete Blocks
Forming Part of Sentence 9.20.2.7.(1)
Type of Unit
Minimum Compressive Strength Over Net Area, MPa
Exposed to Weather Not Exposed to Weather
Solid or hollow concrete blocks 15 10
Solid loadbearing cellular blocks Not permitted 5
Solid non-loadbearing cellular blocks Not permitted 2
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
7) Grout used for reinforced masonry shall be placed in accordance with the requirements of CSAA371,
“Masonry Construction for Buildings.”
9.20.4. Mortar Joints
9.20.4.1. Thickness
1) Except as provided in Sentence(2), mortar joint thickness for burned clay brick and concrete masonry units
shall be 10mm.
2) Permitted tolerances in head and bed joints shall be not more than ± 5mm.
9.20.4.2. Solid Masonry Units
1) Solid masonry units shall be laid with full head and bed joints.
9.20.4.3. Laying of Masonry Units
1) Hollow masonry units shall be laid with mortar applied to head and bed joints of both inner and outer face
shells.
2) Vertically aligned webs of hollow masonry units shall be laid in a full bed of mortar
a) under the starting course,
Table 9.20.3.2.-A
Mortar Use
Forming Part of Sentence 9.20.3.2.(1)
Location Building Element Mortar Type
Exterior, Above Ground
Loadbearing walls and columns S
Non-loadbearing walls and columns N or S
Parapets, chimneys, masonry veneer N or S
Exterior, At or Below Ground Foundation walls and columns S
Interior
Loadbearing walls and columns N
Non-loadbearing walls and columns N
Table 9.20.3.2.-B
Mortar Mix Proportions (by volume)
Forming Part of Sentence 9.20.3.2.(3)
Mortar Type Portland Cement Lime Masonry Cement Type N Masonry Cement Type S
Fine Aggregate
(damp, loose-state sand)
Type S
1 ½ – – 3½ to 4½
–––12¼ to 3
½ – 1 – 3½ to 4½
Type N
11––4½ to 6
––1–2¼ to 3
Table 9.20.3.2.-C
Grout Mix Proportions (by volume)
Forming Part of Sentence 9.20.3.2.(4)
Portland Cement Lime Fine Aggregate (sand) Coarse Aggregate
1 0 to 1/10
2¼ to 3 times the sum of the
cement and lime volumes
1 to 2 times the sum of the
cement and lime volumes
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
b) in all courses of columns, and
c) where adjacent to cells or cavities that are to be filled with grout.
3) Except for head joints left open for weep holes and ventilation, solid masonry units shall be laid with full head
and bed joints.
9.20.5. Masonry Support
9.20.5.1. Masonry Support
1) All masonry shall be supported on masonry, concrete or steel, except that masonry veneer walls may be
supported on foundations of wood frame constructed in conformance with Sentence9.15.2.4.(1).
(SeeNoteA-9.20.5.1.(1).)
2) Every masonry wall shall be at least as thick as the wall it supports, except as otherwise permitted in
Article9.20.12.2.
9.20.5.2. Lintels or Arches
1) Masonry over openings shall be supported by steel, masonry or reinforced concrete lintels, or masonry arches.
2) Steel angle lintels supporting masonry veneer above openings shall
a) conform to Table9.20.5.2., and
b) have a bearing length not less than 90 mm.
3) Steel angle lintels supporting masonry other than veneer, masonry and reinforced concrete lintels, and
masonry arches shall be designed in accordance with Part4 to support the imposed load.
4) Steel angle lintels supporting masonry shall be prime painted or otherwise protected from corrosion.
9.20.6. Thickness and Height
9.20.6.1. Thickness of Exterior Walls
1) Masonry exterior walls, other than cavity walls, in 1-storey buildings and the top storeys of 2- and 3-storey
buildings shall be not less than 140mm thick, provided the walls are not more than 2.8m high at the eaves and 4.6m
high at the peaks of gable ends.
2) The exterior walls of the bottom storeys of 2-storey buildings, and exterior walls of the bottom 2 storeys of
3-storey buildings shall be not less than 190mm thick.
3) In exterior walls composed of more than one wythe, each wythe shall be not less than 90 mm thick.
9.20.6.2. Cavity Walls
1) Cavity walls shall be made with not less than 90mm wide units if the joints are raked and not less than
75mm wide units if the joints are not raked.
Table 9.20.5.2.
Maximum Allowable Spans for Steel Lintels Supporting Masonry Veneer
Forming Part of Sentence 9.20.5.2.(2)
Minimum Angle Size, mm Maximum Allowable Spans, m
Vertical Leg Horizontal Leg Thickness
Supporting
75mm Brick
Supporting
90mm Brick
Supporting
100mm Stone
89 76 6.4 2.55 – –
89 89 6.4 2.59 2.47 2.30
102 89 6.4 2.79 2.66 2.48
127 89 7.9 3.47 3.31 3.08
127 89 11 3.643.483.24
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
2) The width of a cavity in a cavity wall shall be not less than 50mm and not greater than 150 mm.
3) The minimum thickness of cavity walls above the supporting base shall be 230 mm for the top 7.6m and
330mm for the remaining portion, except that where 75mm wide units are used, the wall height above the top of
the foundation wall shall not exceed 6m.
9.20.6.3. Thickness of Interior Walls
1) The thickness of loadbearing interior walls shall be determined on the basis of the maximum lateral support
spacing as provided in Sentences9.20.10.1.(2) and(3).
2) The thickness of interior non-loadbearing walls shall be
a) determined on the basis of the maximum lateral support spacing as provided in Sentences9.20.10.1.(2)
and(3), and
b) in any case, not less than 65mm.
9.20.6.4. Masonry Veneer
1) Except for masonry veneer where each masonry unit is supported individually by the structural backing,
masonry veneer shall consist of solid masonry units not less than 75mm thick.
2) Veneer described in Sentence(1) over wood-frame walls shall have not less than a 25mm air space behind
the veneer.
3) Masonry veneer less than 90mm thick shall have unraked joints.
4) Masonry veneer shall conform to Subsection4.3.2., where the masonry units are required to be individually
supported by the structural backing.
9.20.6.5. Parapet Walls
1) The height of parapet walls above the adjacent roof surface shall be not more than 3 times the parapet
wall thickness.
2) Parapet walls shall be solid masonry
a) with the cells of hollow or semi-solid units filled with mortar, grout, or concrete, and
b) that extends from the top of the parapet to not less than 300mm below the adjacent roof level.
9.20.6.6. Stone or Concrete Facings
1) Slab and panel facings of precast concrete and natural or artifical stone shall conform to Subsection4.3.2.
9.20.7. Chases and Recesses
9.20.7.1. Maximum Dimensions
1) Except as permitted in Sentence9.20.7.2.(2) and Article9.20.7.4., the depth of any chase or recess shall not
exceed one third the thickness of the wall, and the width of the chase or recess shall not exceed 500mm.
9.20.7.2. Minimum Wall Thickness
1) Except as permitted in Sentence(2) and Article9.20.7.4., no chase or recess shall be constructed in any wall
190mm or less in thickness.
2) Recesses may be constructed in 190mm walls provided they do not exceed 100mm in depth, 750mm in
height and 500mm in width.
9.20.7.3. Separation of Chases or Recesses
1) Chases and recesses shall be not less than
a) 4times the wall thickness apart, and
b) 600mm away from any pilaster, cross wall, buttress or other vertical element providing required lateral
support for the wall.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
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9.20.7.4. Non-Conforming Chases or Recesses
1) Chases or recesses that do not conform to the limits specified in Articles9.20.7.1. to9.20.7.3. shall be
considered as openings, and any masonry supported above such a chase or recess shall be supported by a lintel or arch
as provided in Article9.20.5.2.
9.20.7.5. Chases or Recesses Cut into Walls
1) Chases and recesses shall not be cut into walls made with hollow units after the masonry units are in place.
9.20.8. Support of Loads
9.20.8.1. Capping of Hollow Masonry Walls
1) Except as permitted in Sentence(2), loadbearing walls of hollow masonry units supporting roof or floor
framing members shall be capped with not less than 50mm of solid masonry or have the top course filled
with concrete.
2) Capping required in Sentence(1) may be omitted where the roof framing is supported on a wood plate not
less than 38mm by 89mm.
9.20.8.2. Cavity Walls Supporting Framing Members
1) Floor joists supported on cavity walls shall be supported on solid masonry units not less than 57mm high.
2) Floor joists described in Sentence(1) shall not project into the cavity.
3) Roof and ceiling framing members bearing on cavity walls shall be supported on
a) solid masonry units not less than 57mm high that bridge the full thickness of the wall, or
b) a wood plate not less than 38mm thick, bearing not less than 50mm on each wythe.
9.20.8.3. Bearing of Beams and Joists
1) The bearing area under beams and joists shall be sufficient to carry the supported load.
2) In no case shall the minimum length of end bearing of beams supported on masonry be less than 90mm.
3) The length of end bearing of floor, roof or ceiling joists supported on masonry shall be not less than 40mm.
9.20.8.4. Support of Beams and Columns
1) Beams and columns supported on masonry walls shall be supported on pilasters where the thickness of the
masonry wall or wythe is less than 190mm.
2) Not less than 190mm depth of solid masonry or concrete shall be provided under the beam or column
referred to in Sentence(1).
3) Pilasters required in Sentence(1) shall be bonded or tied to masonry walls.
4) Concrete pilasters required in Sentence(1) shall be not less than 50mm by 300mm.
5) Unit masonry pilasters required in Sentence(1) shall be not less than 100mm by 290mm.
9.20.8.5. Projection of Masonry Veneer Beyond Supporting Members
1) Masonry veneer of solid masonry units resting on a bearing support shall not project more than one third of
the thickness of the veneer. (SeeNoteA-9.20.8.5.(1).)
2) Where the masonry veneer described in Sentence(1) is rough stone masonry,
a) the projection shall be measured as the average projection of the units, and
b) the thickness of the veneer shall be measured as the average thickness of the veneer.
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British Columbia Building Code 2018 Division B
9.20.9. Bonding and Tying
9.20.9.1. Joints to be Offset or Reinforced
1) Vertical joints in adjacent masonry courses shall be offset unless each wythe of masonry is reinforced with the
equivalent of not less than 2corrosion-resistant steel bars of 3.76mm diam placed in the horizontal joints at vertical
intervals not exceeding 460mm.
2) Where joints in the reinforcing referred to in Sentence(1) occur, the bars shall be lapped not less than
150mm.
9.20.9.2. Bonding or Tying of Other than Masonry Veneer
1) Except as provided in Article9.20.9.5. regarding masonry veneer, masonry walls that consist of 2or more
wythes shall have the wythes bonded or tied together with masonry bonding units as described in Article9.20.9.3. or
with metal ties as described in Article9.20.9.4.
9.20.9.3. Bonding
1) Where wythes are bonded together with masonry units, the bonding units shall comprise not less than 4% of
the wall surface area.
2) Bonding units described in Sentence(1) shall be spaced not more than 600mm vertically and horizontally in
the case of brick masonry and 900mm o.c. in the case of block or tile.
3) Units described in Sentence(1) shall extend not less than 90mm into adjacent wythes.
9.20.9.4. Tying
1) Where 2 or more wythes are tied together with metal ties of the individual rod type, the ties shall conform to
the requirements in Sentences(3) to(6).
2) Other ties may be used where it can be shown that such ties provide walls that are at least as strong and as
durable as those made with the individual rod type.
3) Metal ties of the individual rod type shall
a) be corrosion-resistant,
b) have a minimum cross-sectional area of not less than 17.8mm
2
, and
c) have not less than a 50mm portion bent at right angles at each end.
4) Metal ties of the individual rod type shall
a) extend from within 25mm of the outer face of the wall to within 25mm of the inner face of the wall,
b) be completely embedded in mortar except for the portion exposed in cavity walls, and
c) be staggered from course to course.
5) Where 2 or more wythes in walls other than cavity walls and masonry veneer/masonry backing walls are tied
together with metal ties of the individual rod type, the space between wythes shall be completely filled with mortar.
6) Ties described in Sentence(5) shall be
a) located within 300mm of openings and spaced not more than 900mm apart around openings, and
b) spaced not more than 900mm apart horizontally and 460mm apart vertically at other locations.
7) Except as required in Sentences(8) and(9), where the inner and outer wythes of cavity walls are tied with
individual wire ties, the ties shall be spaced not more than 900mm apart horizontally and 400mm apart vertically.
8) Within 100mm of the bottom of each floor or roof assembly where the cavity extends below the assemblies,
the ties described in Sentence(7) shall be spaced not more than 600mm apart horizontally.
9) Within 300mm of any openings, the ties described in Sentence(7) shall be spaced not more than
900mm apart.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.20.9.5. Ties for Masonry Veneer
1) Masonry veneer 75mm or more in thickness and resting on a bearing support shall be tied to masonry
backing or to wood framing members with straps that are
a) corrosion-resistant,
b) not less than 0.76mm thick,
c) not less than 22mm wide,
d) shaped to provide a key with the mortar, and
e) spaced in accordance with Table9.20.9.5.
2) Straps described in Sentence(1) that are fastened to wood framing members shall be
a) bent at a right angle within 6mm from the fastener, and
b) fastened with corrosion-resistant 3.18mm diam screws or spiral nails having a wood penetration of not less
than 63mm.
3) Masonry veneer individually supported by masonry or wood-frame backing shall be secured to the backing in
conformance with Subsection4.3.2.
9.20.9.6. Reinforcing for Glass Block
1) Glass block shall have horizontal joint reinforcement of 2corrosion-resistant bars of not less than 3.76mm
diam or expanded metal strips not less than 75mm wide
a) spaced at vertical intervals of not more than 600mm for units 200mm or less in height, and
b) installed in every horizontal joint for units higher than 200mm.
2) Reinforcement required in Sentence(1) shall be lapped not less than 150mm.
9.20.10. Lateral Support
9.20.10.1. Lateral Support Required
1) Masonry walls shall be laterally supported by floor or roof construction or by intersecting masonry walls or
buttresses.
2) The spacing of supports required in Sentence(1) shall be not more than
a) 20 times the wall thickness for all loadbearing walls and exterior non-loadbearing walls, and
b) 36 times the wall thickness for interior non-loadbearing walls.
3) In applying Sentence(2), the thickness of cavity walls shall be taken as the greater of
a) two-thirds of the sum of the thicknesses of the wythes, or
b) the thickness of the thicker wythe.
4) Floor and roof constructions providing lateral support for walls as required in Sentence(1) shall be
constructed to transfer lateral loads to walls or buttresses approximately at right angles to the laterally supported walls.
Table 9.20.9.5.
Veneer Tie Spacing
Forming Part of Sentence 9.20.9.5.(1)
Maximum Vertical Spacing, mm Maximum Horizontal Spacing, mm
400 800
500 600
600 400
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British Columbia Building Code 2018 Division B
9.20.11. Anchorage of Roofs, Floors and Intersecting Walls
9.20.11.1. Anchorage to Floor or Roof Assemblies where Masonry Walls Require Lateral
Support
1) Where required to receive lateral support (seeSubsection9.20.10.), masonry walls shall be anchored to each
floor or roof assembly at maximum intervals of 2m, except that anchorage to floor joists not more than 1m above
grade may be omitted.
2) Anchors required in Sentence(1) shall be corrosion-resistant and be not less than the equivalent of 40mm by
4.76mm thick steel straps.
3) Anchors required in Sentence(1) shall be shaped to provide a mechanical key with the masonry and shall be
securely fastened to the horizontal support to develop the full strength of the anchor.
4) When joists are parallel to the wall, anchors required in Sentence(1) shall extend across not less than 3 joists.
9.20.11.2. Bonding and Tying Intersecting Masonry Walls where Walls Require Lateral
Support
1) Where required to provide lateral support, intersecting walls shall be bonded or tied together.
2) Where bonding is used to satisfy the requirements of Sentence(1), 50% of the adjacent masonry units in the
intersecting wall, distributed uniformly over the height of the intersection, shall be embedded in the laterally
supported wall.
3) Where tying is used to satisfy the requirements of Sentence(1), the ties shall be
a) corrosion-resistant metal,
b) equivalent to not less than 4.76mm by 40mm steel strapping,
c) spaced not more than 800mm o.c. vertically, and
d) shaped at both ends to provide sufficient mechanical key to develop the strength of the ties.
9.20.11.3. Anchoring Intersecting Wood-Frame Walls to Masonry Walls
1) Wood-frame walls shall be anchored to masonry walls that they intersect with not less than 4.76mm diam
corrosion-resistant steel rods spaced not more than 900mm o.c. vertically.
2) Anchors required in Sentence(1) shall be fastened to the wood framing at one end and shaped to provide a
mechanical key at the other end to develop the strength of the anchor.
9.20.11.4. Anchoring Wood-Frame Roof Systems to Masonry Walls
1) Except as permitted in Sentence(2), roof systems of wood-frame construction shall be anchored to exterior
masonry walls by not less than 12.7mm diam anchor bolts,
a) spaced not more than 2.4m apart,
b) embedded not less than 90mm into the masonry, and
c) fastened to a rafter plate of not less than 38mm thick lumber.
2) The roof system described in Sentence(1) is permitted to be anchored by nailing the wall furring strips to the
side of the rafter plate.
9.20.11.5. Anchoring Masonry Cornices, Sills and Trim to Masonry Walls
1) Cornices, sills or other trim of masonry material which project beyond the wall face shall have not less than
65% of their mass, but not less than 90mm, within the wall or shall be adequately anchored to the wall with
corrosion-resistant anchors.
9.20.11.6. Anchoring to Masonry Piers
1) Where anchor bolts are to be placed in the top of a masonry pier, the pier shall conform to the requirements
of Sentence9.15.2.3.(4) and shall be capped with concrete or reinforced masonry not less than 200mm thick.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
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9.20.12. Corbelling
9.20.12.1. Corbelling
1) All corbelling shall consist of solid masonry units.
2) The units referred to in Sentence(1) shall be corbelled so that the horizontal projection of any unit does not
exceed 25mm and the total projection does not exceed one third of the total wall thickness.
9.20.12.2. Corbelling for Cavity Walls
1) Cavity walls of greater thickness than the foundation wall on which they rest shall not be corbelled but may
project 25mm over the outer face of the foundation wall disregarding parging.
2) Where the foundation wall referred to in Sentence(1) is unit masonry, it is permitted to be corbelled to meet
flush with the inner face of a cavity wall provided
a) the projection of each course does not exceed half the height or one third the thickness of the corbelled unit,
and
b) the total corbel does not exceed one third of the foundation wall thickness.
(SeeNoteA-9.20.12.2.(2).)
9.20.12.3. Corbelling for Masonry Veneer
1) Masonry veneer resting on a bearing support shall not project more than 25mm beyond the supporting base
where the veneer is not less than 90mm thick, and 12mm beyond the supporting base where the veneer is less than
90mm thick.
2) In the case of rough stone veneer, the projection, measured as the average projection of the stone units, shall
not exceed one-third the bed width beyond the supporting base.
9.20.13. Control of Rainwater Penetration
9.20.13.1. Materials for Flashing
1) Materials used for flashing shall conform to Table9.20.13.1.
2) Aluminum flashing in contact with masonry or concrete shall be effectively coated or separated from the
masonry or concrete by an impervious membrane.
Table 9.20.13.1.
Flashing Materials
Forming Part of Sentence 9.20.13.1.(1)
Material
Minimum Thickness, mm
Exposed Flashing Concealed Flashing
Aluminum 0.48 –
Copper 0.46 0.46
Copper or aluminum laminated to felt or kraft
paper
–0.05
Galvanized steel 0.33 0.33
Lead sheet 1.73 1.73
Polyethylene – 0.50
Roll roofing, Type S – standard
Zinc 0.46 0.46
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.20.13.2. Fastening of Flashing
1) Fastening devices for flashing shall be corrosion-resistant and, where metal flashing is used, shall be
compatible with the flashing with respect to galvanic action.
9.20.13.3. Location of Flashing
1) Flashing shall be installed in masonry and masonry veneer walls
a) beneath jointed masonry window sills,
b) over the back and top of parapet walls,
c) over the heads of glass block panels,
d) beneath weep holes, and
e) over the heads of window or door openings in exterior walls when the vertical distance between the top of a
window or door frame and the bottom edge of the eave exceeds one-quarter of the horizontal eave overhang.
9.20.13.4. Extension of Flashing
1) When installed beneath jointed masonry window sills or over the heads of openings, flashing shall extend
from the front edge of the masonry up behind the sill or lintel.
9.20.13.5. Flashing for Weep Holes in Masonry/Masonry Walls
1) Flashing beneath weep holes in cavity walls and masonry veneer/masonry backing walls shall
a) be bedded not less than 25mm in the inside wythe,
b) extend to not less than 5mm beyond the outer face of the building element below the flashing, and
c) be installed with a nominally horizontal slope toward the outside wythe.
9.20.13.6. Flashing for Weep Holes in Masonry Veneer
1) Flashing beneath weep holes in masonry veneer over masonry backing walls shall conform to the flashing
requirements for cavity walls and masonry veneer/masonry backing walls in Article9.20.13.5.
2) Flashing beneath weep holes in masonry veneer over wood-frame walls shall be installed so that it extends
from a point not less than 5mm beyond the outer face of the building element below the flashing to a point 150mm
up the wood-frame wall.
3) Where the frame wall is sheathed with a sheathing membrane, a non-wood-based rigid exterior insulating
sheathing or a semi-rigid insulating sheathing with an integral sheathing membrane, the flashing shall be installed
behind the sheathing membrane or insulating sheathing.
4) Flashing described in Sentence(2) is permitted to conform to the requirements for concealed flashing in
Table9.20.13.1.
9.20.13.7. Flashing Joints
1) Joints in flashing shall be made watertight.
9.20.13.8. Required Weep Holes
1) Weep holes spaced not more than 800mm apart shall be provided at the bottom of
a) cavities in cavity walls, and
b) cavities or air spaces in masonry veneer walls.
2) The cavities or air spaces described in Sentence(1) shall include those above lintels over window and door
openings required to be flashed in conformance with Article9.20.13.3.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.20.13.9. Protection of Interior Finish
1) Except as provided in Sentence(3), where the interior finish of the exterior walls of a building is a type that
may be damaged by moisture, exterior masonry walls, other than cavity walls or walls that are protected for their full
height by a roof of a carport or porch, shall be covered on the interior surface with sheathing membrane conforming
to CAN/CGSB-51.32-M, “Sheathing, Membrane, Breather Type,” lapped not less than 100mm at the joints.
2) In situations described in Sentence(1), flashing shall be provided where water will accumulate, to lead it to
the exterior.
3) Where insulation that effectively limits the passage of water is applied by a waterproof adhesive or mortar
directly to parged masonry, the requirements for sheathing membrane in Sentence(1) do not apply.
(SeeNoteA-9.20.13.9.(3).)
9.20.13.10. Mortar Droppings
1) Cavity walls shall be constructed so that mortar droppings are prevented from forming a bridge to allow the
passage of rain water across the cavity.
9.20.13.11. Caulking at Door and Window Frames
1) The junction of door and window frames with masonry shall be caulked in conformance with
Subsection9.27.4.
9.20.13.12. Drips beneath Window Sills
1) Where no flashing is installed beneath window sills, such sills shall be provided with a drip not less than
25mm from the wall surface.
9.20.14. Protection during Work
9.20.14.1. Laying Temperature of Mortar and Masonry
1) Mortar and masonry shall be maintained at a temperature not below 5°C during installation and for not less
than 48h after installation.
2) No frozen material shall be used in mortar mix.
9.20.14.2. Protection from Weather
1) The top surface of uncompleted masonry exposed to the weather shall be completely covered with a
waterproofing material when construction is not in progress.
9.20.15. Reinforcement for Earthquake Resistance
9.20.15.1. Amount of Reinforcement
1) Where reinforcement is required in this Section, masonry walls shall be reinforced horizontally and vertically
with steel having a total cross-sectional area of not less than 0.002times the horizontal cross-sectional area of the wall,
so that not less than one-third of the required steel area is installed either horizontally or vertically and the remainder
in the other direction.
9.20.15.2. Installation Standard
1) Where reinforcement for masonry is required in this Section, it shall be installed in conformance with the
requirements for reinforced masonry as contained in CSAA371, “Masonry Construction for Buildings.”
9.20.16. Corrosion Resistance
9.20.16.1. Corrosion Resistance of Connectors
1) Carbon steel connectors required to be corrosion-resistant shall be galvanized to at least the minimum
standards in Table9.20.16.1.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.20.17. Above-Ground Flat Insulating Concrete Form Walls
9.20.17.1. Thickness of Flat Insulating Concrete Form Walls
1) The thickness of the concrete in flat insulating concrete form walls not in contact with the ground shall be
a) not less than 140mm, and
b) constant for the entire height of the wall.
9.20.17.2. Reinforcement for Flat Insulating Concrete Form Walls
1) Horizontal reinforcement in above-grade flat insulating concrete form walls shall
a) consist of
i) one 10M bar placed not more than 300mm from the top of the wall, and
ii) 10M bars at 600mm o.c., and
b) be placed in the middle third of the wall section.
2) Vertical reinforcement in above-grade flat insulating concrete form walls shall
a) consist of 10M bars at 400mm o.c., and
b) be placed in the middle third of the wall section.
3) Vertical reinforcement required by Sentence(2) and interrupted by wall openings shall be placed not more
than 600mm from each side of the opening.
9.20.17.3. Openings in Non-Loadbearing Flat Insulating Concrete Form Walls
1) No openings shall occur within 1 200mm of interior and exterior corners of exterior non-loadbearing flat
insulating concrete form walls.
2) Portions of walls above openings in non-loadbearing flat insulating concrete form walls shall have a minimum
depth of concrete of no less than 200mm across the width of the opening.
3) Openings that are more than 600mm but not more than 3 000mm in width in non-loadbearing flat
insulating concrete form walls shall be reinforced at the top and bottom with one 10M bar.
4) Openings more than 3 000mm in width in non-loadbearing flat insulating concrete form walls shall be
reinforced on all four sides with two 10M bars.
5) Reinforcing bars described in Sentences(3) and(4) shall extend 600mm beyond the edges of the opening.
6) The cumulative width of openings in non-loadbearing flat insulating concrete form walls shall not make up
more than 70% of the length of any wall.
Table 9.20.16.1.
Minimum Requirements for Galvanizing
Forming Part of Sentence 9.20.16.1.(1)
Connector Material ASTM Standard Coating Class or Thickness
Wire ties and continuous reinforcing
(hot-dipped galvanizing)
ASTM A 153/A 153M Class B2 or 458 g/m
2
Hardware and bolts ASTM A 153/A 153M See ASTM A 153/A 153M
Strip, plate, bars and rolled sections
(not less than 3.18 mm thick)
ASTM A 123/A 123M 610 g/m
2
Sheet (less than 3.18 mm thick) ASTM A 123/A 123M 305 g/m
2
on material 0.76 mm thick
(1)
Notes to Table9.20.16.1.:
(1) ASTM A 123/A 123M does not apply to metal less than 3.18 mm thick. Galvanizing coatings may be interpolated for thicknesses between 3.18 mm and 0.76 mm.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.20.17.4. Openings in Loadbearing Flat Insulating Concrete Form Walls
1) No openings shall occur within 1 200mm of interior and exterior corners of exterior loadbearing flat
insulating concrete form walls.
2) In loadbearing flat insulating concrete form walls, lintels shall be provided over all openings wider
than 900mm.
3) Lintels described in Sentence(2) shall be constructed in accordance with Span Table9.20.17.4.-A,
9.20.17.4.-B or 9.20.17.4.-C.
4) Lintels described in Sentence(2) over openings wider than 1 200mm shall be reinforced for shear with 10M
stirrups at a maximum spacing of half the distance from the bottom reinforcing bar to the top of the lintel.
9.20.17.5. Framing Supported on Flat Insulating Concrete Form Walls
1) Floor joists supported on the side of flat insulating concrete form walls shall be supported with joist hangers
secured to wood ledger boards.
2) The ledger boards referred to in Sentence(1) shall be not less than
a) 38mm thick, and
b) the depth of the floor joists.
3) Anchor bolts shall be used to secure ledger boards to flat insulating concrete form walls and shall be
a) embedded in the wall to a depth not less than 100 mm, and
b) spaced in accordance with Table9.20.17.5.
4) Floor joists and building frames supported on the top of flat insulating concrete form walls shall be anchored
in conformance with Article9.23.6.1.
9.20.17.6. Anchoring of Roof Framing to the Top of Flat Insulating Concrete Form Walls
1) Roof framing supported on the top of flat insulating concrete form walls shall be fixed to the top plates,
which shall be anchored to the wall with anchor bolts
a) not less than 12.7mm in diameter, and
b) spaced at not more than 1 200mm o.c.
2) The anchor bolts described in Sentence(1) shall be placed in the centre of the flat insulating concrete form
wall and shall be embedded no less than 100mm into the concrete.
3) Attachment of roof framing to wood top plates shall be in accordance with Table9.23.3.4.
9.20.17.7. Protection from Precipitation and Damage
1) Above-ground flat insulating concrete form walls shall be protected from precipitation and damage in
conformance with Section9.27.
Table 9.20.17.5.
Maximum Anchor Bolt Spacing for the Connection of Floor Ledgers to Flat Insulating Concrete Form Walls
Forming Part of Sentence 9.20.17.5.(3)
Maximum Clear Floor Span, m
Maximum Anchor Bolt Spacing, mm
Staggered 12.7mm Diameter Anchor Bolts Staggered 16mm Diameter Anchor Bolts
2.44 450 500
3.0 400 450
4.0 300 400
5.0 275 325
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.21. Masonry and Concrete Chimneys and Flues
9.21.1. General
9.21.1.1. Application
1) This Section applies to
a) rectangular masonry or concrete chimneys not more than 12m in height serving fireplaces or serving appliances
having a combined total rated heat output of 120kW or less, and
b) flue pipes connected to such chimneys.
2) Chimneys, other than those described in Sentence(1), gas vents and flue pipes serving gas-, oil- or
solid-fuel-burning appliances and their associated equipment, including stoves, cooktops, ovens and space heaters,
covered by the standards referenced in Sentences9.33.5.2.(1) and9.33.5.3.(1) shall conform to Subsection9.33.10.
3) Chimneys and flue pipes other than those described in Sentences(1) and(2) shall conform to Section6.3.
9.21.1.2. Chimney or Flue Pipe Walls
1) The walls of any chimney or flue pipe shall be constructed so as to be smoke- and flame-tight.
9.21.2. Chimney Flues
9.21.2.1. Chimney Flue Limitations
1) A chimney flue that serves a fireplace or incinerator shall not serve any other appliance.
2) A chimney flue that serves a solid-fuel-burning appliance shall not be connected to a natural-gas- or
propane-fired appliance.
3) A chimney flue that serves a solid-fuel-burning appliance shall not be connected to an oil-burning appliance
unless the solid-fuel-burning appliance is certified for such installation and the installation of both appliances meets
the requirements of the relevant standards referenced in Article9.33.5.2.
9.21.2.2. Connections of More Than One Appliance
1) Except as required by Article9.21.2.1., where two or more fuel-burning appliances are connected to the same
chimney flue, the connections shall be made as described in Sentences(2) to(4) and an adequate draft shall be
provided for the connected appliances in conformance with the requirements of applicable provincial or territorial
regulations or municipal bylaws or, in the absence of such regulations or bylaws, with the requirements of the
relevant standards listed in Subsection9.33.10.
2) Where 2 or more fuel-burning appliances are connected to the same chimney flue, the appliances shall be
located on the same storey.
3) The connection referred to in Sentence(2) for a solid-fuel-burning appliance shall be made below
connections for appliances burning other fuels.
4) The connection referred to in Sentence(2) for a liquid-fuel-burning appliance shall be made below any
connections for appliances burning natural gas or propane.
9.21.2.3. Inclined Chimney Flues
1) Chimney flues shall not be inclined more than 45° to the vertical.
9.21.2.4. Size of Chimney Flues
1) Except for chimneys serving fireplaces, the size of a chimney flue shall conform to the requirements of the
appliance installation standards referenced in Sentences9.33.5.2.(1) and9.33.5.3.(1).
2) Where a chimney flue serves only one appliance, the flue area shall be at least equal to that of the flue pipe
connected to it.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.21.2.5. Fireplace Chimneys
1) The size of a chimney flue serving a masonry fireplace shall conform to Table9.21.2.5.-A or9.21.2.5.-B.
Table 9.21.2.5.-A
Diameter of Round Flues for Fireplace Chimneys
Forming Part of Sentence 9.21.2.5.(1)
Fireplace
Opening, m
2
Chimney Height, m
3.0 to 4.5 > 4.5 to 5.9 > 5.9 to 8.9 > 8.9 to 12
Flue Diameter, mm
min. max. min. max. min. max. min. max.
up to 0.150 110 170 100 160 90 150 90 150
0.151 to 0.250 150 210 130 190 130 190 120 180
0.251 to 0.350 180 240 160 220 150 210 140 200
0.351 to 0.500 220 280 200 260 190 250 170 230
0.501 to 0.650 260 320 230 290 220 280 200 260
0.651 to 0.800 290 350 260 320 240 300 220 280
0.801 to 1.00 330 390 290 350 270 330 250 310
1.01 to 1.20 360 420 320 380 300 360 270 330
1.21 to 1.40 390 450 350 410 330 390 300 360
1.41 to 1.60 420 480 380 440 350 410 320 380
1.61 to 1.80 – – 400 460 370 430 340 400
1.81 to 2.00 – – – – 400 460 360 420
2.01 to 2.20 – – – – – – 380 440
Table 9.21.2.5.-B
Rectangular Flue Sizes for Fireplace Chimneys
Forming Part of Sentence 9.21.2.5.(1)
Fireplace
Opening, m
2
Chimney Height, m
3.0 to 4.5 > 4.5 to 5.9 > 5.9 to 8.9 > 8.9 to 12
Flue Size, mm
min. max. min. max. min. max. min. max.
up to 0.150 200 × 200 200 × 200 100 × 200 100 × 200 100 × 200 100 × 200 100 × 200 100 × 200
0.151 to 0.250 200 × 200 200 × 200 200 × 200 200 × 200 200 × 200 200 × 200 200 × 200 200 × 200
0.251 to 0.350 200 × 300 200 × 300 200 × 200 200 × 300 200 × 200 200 × 200 200 × 200 200 × 200
0.351 to 0.500 300 × 300 300 × 300 200 × 300 200 × 300 200 × 300 200 × 300 200 × 200 200 × 300
0.501 to 0.650 300 × 300 300 × 400 300 × 300 300 × 300 300 × 300 300 × 300 200 × 300 200 × 300
0.651 to 0.800 300 × 400 300 × 400 300 × 300 300 × 400 300 × 300 300 × 300 300 × 300 300 × 300
0.801 to 1.00 400 × 400 400 × 400 300 × 400 300 × 400 300 × 400 300 × 400 300 × 300 300 × 300
1.01 to 1.20 400 × 400 400 × 400 400 × 400 400 × 400 300 × 400 300 × 400 300 × 400 300 × 400
1.21 to 1.40 – – 400 × 400 400 × 400 400 × 400 400 × 400 300 × 400 300 × 400
1.41 to 1.60 – – – – 400 × 400 400 × 400 400 × 400 400 × 400
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.21.2.6. Oval Chimney Flues
1) The width of an oval chimney flue shall be not less than two-thirds its breadth.
9.21.3. Chimney Lining
9.21.3.1. Lining Materials
1) Every masonry or concrete chimney shall have a lining of clay, concrete, firebrick or metal.
9.21.3.2. Joints in Chimney Liners
1) Joints of chimney liners shall be sealed to provide a barrier to the passage of flue gases and condensate into the
cavity between the liner and the surrounding masonry.
2) Joints of clay, concrete or firebrick chimney liners shall be struck flush to provide a straight, smooth, aligned
chimney flue.
9.21.3.3. Clay Liners
1) Clay liners shall conform to CAN/CSA-A324-M, “Clay Flue Liners.”
2) Liners referred to in Sentence(1) shall be not less than 15.9mm thick and shall be capable of resisting,
without softening or cracking, a temperature of 1 100°C.
9.21.3.4. Firebrick Liners
1) Firebrick liners shall conform to ASTM C 27, “Fireclay and High-Alumina Refractory Brick.”
2) Firebrick liners shall be laid with high temperature cement mortar conforming to CAN/CGSB-10.3, “Air
Setting Refractory Mortar.”
9.21.3.5. Concrete Liners
1) Concrete flue liners shall conform to Clause4.2.6.4 of CAN/CSA-A405-M, “Design and Construction of
Masonry Chimneys and Fireplaces.”
9.21.3.6. Metal Liners
1) Metal liners shall be constructed of not less than 0.3mm thick stainless steel.
2) Metal liners referred to in Sentence(1) shall only be used in chimneys serving gas- or oil-burning appliances.
(SeeNoteA-9.21.3.6.(2).)
9.21.3.7. Installation of Chimney Liners
1) Chimney liners shall be installed when the surrounding masonry or concrete is placed.
9.21.3.8. Spaces between Liners and Surrounding Masonry
1) A space not less than 10mm wide shall be left between a chimney liner and surrounding masonry.
1.61 to 1.80 – – – – – – 400 × 400 400 × 400
1.81 to 2.00 – – – – – – 400 × 400 400 × 400
Table 9.21.2.5.-B (continued)
Rectangular Flue Sizes for Fireplace Chimneys
Forming Part of Sentence 9.21.2.5.(1)
Fireplace
Opening, m
2
Chimney Height, m
3.0 to 4.5 > 4.5 to 5.9 > 5.9 to 8.9 > 8.9 to 12
Flue Size, mm
min. max. min. max. min. max. min. max.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) The space required in Sentence(1) shall not be filled with mortar.
9.21.3.9. Mortar for Chimney Liners
1) Chimney liners used in chimneys for solid-fuel-burning appliances shall be laid in a full bed of
a) high temperature cement mortar conforming to CAN/CGSB-10.3, “Air Setting Refractory Mortar,” or
b) mortar consisting of 1 part Portland cement to 3parts sand by volume.
2) Chimney liners used in chimneys for oil- or gas-burning appliances shall be laid in a full bed of mortar
consisting of 1 part Portland cement to 3parts sand by volume.
9.21.3.10. Extension of Chimney Liners
1) Chimney liners shall extend from a point not less than 200mm below the lowest flue pipe connection to a
point not less than 50mm or more than 100mm above the chimney cap.
9.21.4. Masonry and Concrete Chimney Construction
9.21.4.1. Unit Masonry
1) Unit masonry shall conform to Section9.20.
9.21.4.2. Concrete
1) Concrete shall conform to Section9.3.
9.21.4.3. Footings
1) Footings for masonry chimneys and concrete chimneys shall conform to Section9.15.
9.21.4.4. Height of Chimney Flues
1) A chimney flue shall extend not less than
a) 900mm above the highest point at which the chimney comes in contact with the roof, and
b) 600mm above the highest roof surface or structure within 3m of the chimney.
(SeeNoteA-9.21.4.4.(1).)
9.21.4.5. Lateral Stability
1) Except as provided in Sentence(2), chimneys shall be braced in accordance with Subsection4.3.2. to provide
lateral stability under wind loads.
2) A chimney need not be laterally braced provided
a) no horizontal outside dimension is less than 400mm, and
b) the chimney extends not more than 3.6m above a roof or the masonry wall of which it forms a part.
(SeeNoteA-9.21.4.5.(2).)
9.21.4.6. Chimney Caps
1) The top of a chimney shall have a waterproof cap of reinforced concrete, masonry or metal.
2) The cap required in Sentence(1) shall slope from the lining and be provided with a drip not less than 25mm
from the chimney wall.
3) Cast-in-place concrete caps shall be separated from the chimney liner by a bond break and be sealed at that
location.
4) Jointed precast concrete or masonry chimney caps shall have flashing installed beneath the cap extending from
the liner to the drip edge.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.21.4.7. Cleanout
1) A cleanout opening with a metal frame and a tight-fitting metal door shall be installed near the base of the
chimney flue.
9.21.4.8. Wall Thickness
1) The walls of a masonry chimney shall be built of solid masonry units not less than 75mm thick.
9.21.4.9. Separation of Flue Liners
1) Flue liners in the same chimney shall be separated by not less than 75mm of masonry or concrete exclusive of
liners where clay liners are used, or 90mm of firebrick where firebrick liners are used.
2) Flue liners referred to in Sentence(1) shall be installed to prevent significant lateral movement.
9.21.4.10. Flashing
1) Junctions with adjacent materials shall be adequately flashed to shed water.
9.21.5. Clearance from Combustible Construction
9.21.5.1. Clearance from Combustible Materials
1) The clearance between masonry or concrete chimneys and combustible framing shall be not less than
a) 50mm for interior chimneys, and
b) 12mm for exterior chimneys.
(SeeNoteA-9.21.5.1.(1).)
2) A clearance of not less than 150mm shall be provided between a cleanout opening and combustible material.
3) Combustible flooring and subflooring shall have not less than a 12mm clearance from masonry or
concrete chimneys.
9.21.5.2. Sealing of Spaces
1) All spaces between masonry or concrete chimneys and combustible framing shall be sealed top or bottom with
noncombustible material.
9.21.5.3. Support of Joists or Beams
1) Joists or beams may be supported on masonry walls which enclose chimney flues provided the combustible
members are separated from the flue by not less than 290mm of solid masonry.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.22. Fireplaces
9.22.1. General
9.22.1.1. Application
1) Except when otherwise specifically stated herein, this Section applies to masonry fireplaces
constructed on-site.
9.22.1.2. Masonry and Concrete
1) Except as otherwise stated in this Section, unit masonry shall conform to Section9.20. and concrete to
Section9.3.
2) Masonry above openings shall be supported by steel lintels conforming to Sentence9.20.5.2.(2), reinforced
concrete or a masonry arch.
9.22.1.3. Footings
1) Footings for masonry and concrete fireplaces shall conform to Section9.15.
9.22.1.4. Combustion Air
1) Where a supply of combustion air is provided directly to the fire chamber of a fireplace, including a
factory-built fireplace, the installation shall comply with the “Outdoor Air Supply” requirements provided in
CAN/CSA-A405-M, “Design and Construction of Masonry Chimneys and Fireplaces.”
9.22.2. Fireplace Liners
9.22.2.1. Brick or Steel Liners
1) Except where a fireplace is equipped with a steel liner, every fireplace shall have a firebrick liner.
9.22.2.2. Firebrick Liners
1) Firebrick liners shall be not less than
a) 50mm thick for the sides and back, and
b) 25mm thick for the floor.
2) Firebrick liners shall be laid with high temperature cement mortar conforming to CAN/CGSB-10.3,
“Air Setting Refractory Mortar.”
3) Joints between a firebrick liner and the adjacent backing masonry shall be offset.
9.22.2.3. Steel Liners
1) Steel liners for fireplaces shall conform to CAN/ULC-S639-M, “Steel Liner Assemblies for Solid-Fuel
Burning Masonry Fireplaces,” and shall be installed in accordance with the installation instructions in that standard.
9.22.3. Fireplace Walls
9.22.3.1. Thickness of Walls
1) Except as provided in Sentence(2), the thickness of the back and sides of a fireplace, including the thickness
of any firebrick liner, shall be not less than 190mm where a metal liner or a firebrick liner less than 51mm thick is
used.
2) When a steel fireplace liner is used with an air circulating chamber surrounding the firebox, the back and
sides of the fireplace shall consist of
a) solid masonry units not less than 90mm thick, or
b) hollow masonry units not less than 190mm thick.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.22.4. Fire Chamber
9.22.4.1. Fire Chamber Dimensions
1) The distance from the back of the fire chamber to the plane of the fireplace opening shall be not less than
300mm.
9.22.5. Hearth
9.22.5.1. Hearth Extension
1) Except as required in Sentence(2), fireplaces shall have a noncombustible hearth extending not less than
400mm in front of the fireplace opening and not less than 200mm beyond each side of the fireplace opening.
2) Where the fire chamber floor is elevated more than 150mm above the hearth, the dimension of the hearth
measured perpendicular to the plane of the fireplace opening shall be increased by not less than
a) 50mm for an elevation above 150mm and not more than 300 mm, and
b) an additional 25mm for every 50mm in elevation above 300mm.
9.22.5.2. Support of Hearth
1) Except as permitted in Sentence(2), the fire chamber floor and hearth shall be supported on a reinforced
concrete slab not less than 100mm thick at its supports and, if cantilevered, not less than 50mm thick at its
unsupported edge.
2) A hearth for a fireplace with an opening raised not less than 200mm from a combustible floor is permitted to
be supported on that floor provided the requirements of Clauses5.3.6.5. to 5.3.6.7. of CAN/CSA-A405-M, “Design
and Construction of Masonry Chimneys and Fireplaces,” are followed.
9.22.6. Damper
9.22.6.1. Required Damper and Size
1) The throat of every fireplace shall be equipped with a metal damper sufficiently large to cover the full area of
the throat opening.
9.22.7. Smoke Chamber
9.22.7.1. Slope of Smoke Chamber
1) The sides of the smoke chamber connecting a fireplace throat with a flue shall not be sloped at an angle
greater than 45° to the vertical.
9.22.7.2. Wall Thickness
1) The thickness of masonry walls surrounding the smoke chamber shall be not less than 190mm at the sides,
front and back, except that the portions of the back exposed to the outside may be 140mm thick.
9.22.8. Factory-Built Fireplaces
9.22.8.1. Conformance to Standard
1) Factory-built fireplaces and their installation shall conform to CAN/ULC-S610-M, “Factory-Built
Fireplaces.”
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.22.9. Clearance of Combustible Material
9.22.9.1. Clearance to the Fireplace Opening
1) Combustible material shall not be placed on or near the face of a fireplace within 150mm of the fireplace
opening, except that where the combustible material projects more than 38mm out from the face of the fireplace
above the opening, such material shall be not less than 300mm above the top of the opening.
9.22.9.2. Metal Exposed to the Interior
1) Metal exposed to the interior of a fireplace such as the damper control mechanism shall have not less than a
50mm clearance from any combustible material on the face of the fireplace where such metal penetrates through the
face of the fireplace.
9.22.9.3. Clearance to Combustible Framing
1) Not less than a 100mm clearance shall be provided between the back and sides of a fireplace and combustible
framing, except that a 50mm clearance is permitted where the fireplace is located in an exterior wall.
2) Not less than a 50mm clearance shall be provided between the back and sides of the smoke chamber of a
fireplace and combustible framing, except that a 25mm clearance is permitted where the fireplace is located in an
exterior wall.
9.22.9.4. Heat-Circulating Duct Outlets
1) The clearance of combustible material above heat-circulating duct outlets from those outlets shall be not
less than
a) 300mm where the combustible material projects not less than 38mm from the face, and
b) 150mm where the projection is less than 38mm.
9.22.10. Fireplace Inserts and Hearth-Mounted Stoves
9.22.10.1. Appliance Standard
1) Fireplace inserts and hearth-mounted stoves vented through the throat of a fireplace shall conform to
ULC-S628, “Fireplace Inserts.”
9.22.10.2. Installation
1) The installation of fireplace inserts and hearth-mounted stoves vented through the throat of a fireplace shall
conform to CSAB365, “Installation Code for Solid-Fuel-Burning Appliances and Equipment.”
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.23. Wood-Frame Construction
9.23.1. Application
9.23.1.1. Limitations
(SeeNoteA-9.23.1.1.) (Seealso NoteA-9.4.2.1.(1).)
1) This Section applies to constructions where wall, floor and roof planes are generally comprised of lumber
frames of small repetitive structural members, or engineered components, and where
a) roof and wall planes are clad, sheathed or braced on at least one side,
b) the small repetitive structural members are spaced not more than 600mmo.c.,
c) the constructions do not serve as foundations,
d) the specified live load on supported subfloors and floor framing does not exceed 2.4kPa, and
e) the span of any structural member does not exceed 12.20m.
(SeeNoteA-9.23.1.1.(1).)
2) Where the conditions in Sentence(1) are exceeded for wood constructions, the design of the framing and
fastening shall conform to Subsection4.3.1.
9.23.2. General
9.23.2.1. Strength and Rigidity
1) All members shall be so framed, anchored, fastened, tied and braced to provide the necessary strength
and rigidity.
9.23.2.2. Protection from Decay
1) Ends of wood joists, beams and other members framing into masonry or concrete shall be treated to prevent
decay where the bottom of the member is at or below ground level, or a 12mm air space shall be provided at the end
and sides of the member.
2) Air spaces required in Sentence(1) shall not be blocked by insulation, vapour barriers or airtight materials.
9.23.2.3. Protection from Dampness
1) Except as permitted in Sentence(2), wood framing members that are not pressure-treated with a wood
preservative and that are supported on concrete in contact with the ground or fill shall be separated from the concrete
by not less than 0.05mm polyethylene film or TypeS roll roofing.
2) Dampproofing material referred to in Sentence(1) is not required where the wood member is at least
150mm above the ground.
9.23.2.4. Lumber
1) Lumber shall conform to Subsection9.3.2.
9.23.3. Fasteners
9.23.3.1. Standards for Nails and Screws
1) Except as provided in Sentence(2) and unless otherwise indicated, nails specified in this Section shall be
common steel wire nails or common spiral nails conforming to
a) ASTMF1667, “Driven Fasteners: Nails, Spikes, and Staples,” or
b) CSAB111, “Wire Nails, Spikes and Staples.”
2) Nails used to comply with Table9.23.3.4. shall have a diameter not less than that stated in Table9.23.3.1.
(SeeNoteA-9.23.3.1.(2).)
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
3) Wood screws specified in this Section shall conform to ASMEB18.6.1, “Wood Screws (Inch Series).”
(SeeNoteA-9.23.3.1.(3).)
9.23.3.2. Length of Nails
1) All nails shall be long enough so that not less than half their required length penetrates into the
second member.
9.23.3.3. Prevention of Splitting
1) Splitting of wood members shall be minimized by staggering the nails in the direction of the grain and by
keeping nails well in from the edges. (SeeNoteA-9.23.3.3.(1).)
9.23.3.4. Nailing of Framing
1) Except as provided in Sentence(2), nailing of framing shall conform to Table9.23.3.4.
2) Where the bottom wall plate or sole plate of an exterior wall is not nailed to floor joists, rim joists or blocking
in conformance with Table9.23.3.4., the exterior wall is permitted to be fastened to the floor framing by
a) having plywood, OSB or waferboard sheathing extend down over floor framing and fastened to the floor
framing by nails or staples conforming to Article9.23.3.5., or
b) tying the wall framing to the floor framing by galvanized-metal strips
i) 50mm wide,
ii) not less than 0.41mm thick,
iii) spaced not more than 1.2m apart, and
iv) fastened at each end with at least two 63mm nails.
Table 9.23.3.1.
Diameter of Nails
Forming Part of Sentence 9.23.3.1.(2)
Minimum Length of Nails, mm Diameter of Nails, mm
57 2.87
63 3.25
76 3.66
82 3.66
101 or greater 4.88
Table 9.23.3.4.
Nailing for Framing
Forming Part of Sentence 9.23.3.4.(1)
Construction Detail Minimum Length of Nails, mm
Minimum Number or
Maximum Spacing of Nails
Floor joist or blocking perpendicular to sill plate or top wall plate below – toe nail 82 2 per floor joist or blocking
Rim joist, trimmer joist or blocking – supporting walls with required braced wall
panels – to sill plate or top wall plate – toe nail
82 150 mm o.c.
Wood or metal strapping to underside of floor joists 57 2
Cross bridging to joists 57 2 at each end
Double header or trimmer joists 76 300 mm o.c.
Floor joist to stud (balloon construction) 76 2
Ledger strip to wood beam 82 2 per joist
Joist to joist splice (see also Table 9.23.14.8.) 76 2 at each end
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
3) Where the 1-in-50 hourly wind pressure is equal to or greater than 0.8kPa, roof rafters, joists or trusses shall
be tied to the wall framing with connectors that will resist a factored uplift load of 3kN.
Tail joist to adjacent header joist 82 5
(end nailed) around openings 101 3
Each header joist to adjacent trimmer joist 82 5
(end nailed) around openings 101 3
Stud to wall plate (each end) toe nail 63 4
or end nail 82 2
Doubled studs at openings, or studs at walls or wall intersections and corners 76 750 mm o.c.
Doubled top wall plates
(1)
76 600 mm o.c.
Bottom wall plate or sole plate to floor joists, rim joists or blocking
(exterior walls)
(2)
82 400 mm o.c.
Bottom wall plate or sole plate – in required braced wall panels – to floor joists,
rim joists or blocking (exterior walls)
(2)
82 150 mm o.c.
Interior walls to framing or subflooring 82 600 mm o.c.
Required braced wall panels – in interior walls – to framing above and below 82 150 mm o.c.
Horizontal member over openings in non-loadbearing walls – each end 82 2
Lintels to studs 82 2 at each end
Ceiling joist to plate – toe nail each end 82 2
Roof rafter, roof truss or roof joist to plate – toe nail
(3)
82 3
Rafter plate to each ceiling joist 101 2
Rafter to joist (with ridge supported) 76 3
Rafter to joist (with ridge unsupported) 76 see Table 9.23.14.8.
Gusset plate to each rafter at peak 57 4
Rafter to ridge board – toe nail – end nail 82 3
Collar tie to rafter – each end 76 3
Collar tie lateral support to each collar tie 57 2
Jack rafter to hip or valley rafter 82 2
Roof strut to rafter 76 3
Roof strut to loadbearing wall – toe nail 82 2
38 mm × 140 mm or less plank decking to support 82 2
Plank decking wider than 38 mm × 140 mm to support 82 3
38 mm edge laid plank decking to support (toe nail) 76 1
38 mm edge laid plank to each other 76 450 mm o.c.
Notes to Table9.23.3.4.:
(1) See Article 9.23.11.4. for requirements on the nailing of top plates in braced wall bands.
(2) See Sentence 9.23.3.4.(2).
(3) See Sentence 9.23.3.4.(3).
Table 9.23.3.4. (continued)
Nailing for Framing
Forming Part of Sentence 9.23.3.4.(1)
Construction Detail Minimum Length of Nails, mm
Minimum Number or
Maximum Spacing of Nails
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
4) Galvanized-steel straps are deemed to comply with Sentence(3), provided they are
a) 50mm wide,
b) not less than 0.91mm thick, and
c) fastened at each end with at least four 63mm nails.
9.23.3.5. Fasteners for Sheathing or Subflooring
1) Except as provided in Sentences(2) to(4), fastening of sheathing and subflooring shall conform to
Table9.23.3.5.-A.
2) Fastening of roof sheathing and sheathing in required braced wall panels shall conform to Table9.23.3.5.-B,
where
a) the 1-in-50 hourly wind pressure (HWP) is equal to or greater than 0.8kPa and less than 1.2kPa and the
seismic spectral response acceleration, S
a
(0.2), is not more than 0.90, or
b) the seismic spectral response acceleration, S
a
(0.2), is greater than 0.70 and not more than 0.90.
3) Fastening of roof sheathing and sheathing in required braced wall panels shall conform to Table9.23.3.5.-C,
where
Table 9.23.3.5.-A
Fasteners for Subflooring and for Sheathing where the 1-in-50 HWP < 0.8 kPa and S
a
(0.2) ≤ 0.70
Forming Part of Sentence 9.23.3.5.(1)
Element
Minimum Length of Fasteners, mm
Minimum Number or Maximum Spacing of
Fasteners
Common
or Spiral
Nails
Ring
Thread
Nails or
Screws
Roofing
Nails
Staples
Board lumber 184 mm or less wide 51 45 n/a 51 2 per support
Board lumber more than 184 mm wide 51 45 n/a 51 3 per support
Fibreboard sheathing up to 13 mm thick n/a n/a 44 28
150 mm o.c. along edges and 300 mm
o.c. along intermediate supports
Gypsum sheathing up to 13 mm thick n/a n/a 44 n/a
Plywood, OSB or waferboard up to 10 mm thick 51 45 n/a 38
Plywood, OSB or waferboard over 10 mm and up to 20 mm thick 51 45 n/a 51
Plywood, OSB or waferboard over 20 mm and up to 25 mm thick 57 51 n/a n/a
Table 9.23.3.5.-B
Fasteners for Sheathing where 0.8 kPa ≤ 1-in-50 HWP < 1.2 kPa and S
a
(0.2) ≤ 0.90 or where 0.70 < S
a
(0.2) ≤ 0.90
Forming Part of Sentence 9.23.3.5.(2)
Element
Minimum Length of Fasteners, mm
Minimum Number or Maximum Spacing of Fasteners
Common,
Spiral or Ring
Thread Nails
Screws
14-gauge
Staples
Board lumber 184 mm or less wide 63 51 63 2 per support
Board lumber more than 184 mm wide 63 51 63 3 per support
Plywood, OSB or waferboard up to 20 mm thick
(1)
63 51 63 150 mm o.c. along edges and 300 mm o.c. along
intermediate supports; and for roof sheathing where
HWP is equal to or greater than 0.8 kPa and less than
1.2 kPa, 50 mm o.c. within 1 m of the edges of the roof
Plywood, OSB or waferboard over 20 mm and up
to 25 mm thick
63 57 n/a
Notes to Table9.23.3.5.-B:
(1) See Note A-Table 9.23.3.5.-B.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
a) the 1-in-50 hourly wind pressure (HWP) is equal to or greater than 0.8kPa and less than 1.2kPa and the
spectral response acceleration, S
a
(0.2), is not more than 1.8, or
b) the seismic spectral response acceleration, S
a
(0.2), is greater than 0.90 and not more than 1.8.
4) Fastening of sheathing shall conform to Part4,
a) where the 1-in-50 hourly wind pressure is equal to or greater than 1.2kPa, or
b) for required braced wall panels, where the seismic spectral response acceleration, S
a
(0.2), is greater than 1.8.
5) Staples shall not be less than 1.6mm in diameter or thickness, with not less than a 9.5mm crown driven with
the crown parallel to framing.
6) Roofing nails for the attachment of fibreboard or gypsum sheathing shall not be less than 3.2mm in diameter
with a minimum head diameter of 11.1mm.
7) Flooring screws shall not be less than 3.2mm in diameter.
8) The edges of sheathing in a braced wall panel shall be supported and fastened to wood blocking where
a) the seismic spectral response acceleration, S
a
(0.2), is greater than 1.2, or
b) the braced wall panel supports more than a roof of lightweight construction.
9.23.4. Maximum Spans
9.23.4.1. Application
1) Spans provided in this Subsection for joists, beams and lintels supporting floors shall apply only where
a) the floors serve residential areas as described in Table4.1.5.3., or
b) the uniformly distributed live load on the floors does not exceed that specified for residential areas as
described in Table4.1.5.3.
2) Spans for joists, beams and lintels supporting floors shall be determined according to Subsection4.1.3. where
the supported floors
a) serve other than residential areas, or
b) support a uniform live load in excess of that specified for residential areas.
9.23.4.2. Spans for Joists, Rafters and Beams
(SeeNoteA-9.23.4.2.)
1) Except as required in Sentence(2) and Article9.23.14.10., spans for wood joists and rafters shall conform to
the spans shown in Span Tables9.23.4.2.-A to9.23.4.2.-G for the uniform live loads shown in the Tables.
(SeeArticle9.4.2.2.)
Table 9.23.3.5.-C
Fasteners for Sheathing where 0.8 kPa ≤ 1-in-50 HWP < 1.2 kPa and S
a
(0.2) ≤ 1.8 or where 0.90 < S
a
(0.2) ≤ 1.8
Forming Part of Sentence 9.23.3.5.(3)
Element
Minimum Length of Fasteners, mm
Minimum Number or Maximum Spacing of Fasteners
Common, Spiral
or Ring Thread
Nails
Screws
Plywood, OSB or waferboard up to 20 mm thick
(1)
63 51 75 mm o.c. along edges and 300 mm o.c. along intermediate
supports; and for roof sheathing where 1-in-50 HWP is equal
to or greater than 0.8 kPa and less than 1.2 kPa, 50 mm o.c.
within 1 m of the edges of the roof
Plywood, OSB or waferboard over 20 mm and up to
25 mm thick
63 57
Notes to Table9.23.3.5.-C:
(1) See Note A-Table 9.23.3.5.-B.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Spans for floor joists that are not selected from Span Tables9.23.4.2.-A and9.23.4.2.-B and that are required
to be designed for the same loading conditions, shall not exceed the design requirements for uniform loading and
vibration criteria. (SeeNoteA-9.23.4.2.(2).)
3) Spans for built-up wood and glued-laminated timber floor beams shall conform to the spans in Span
Tables9.23.4.2.-H to9.23.4.2.-K. (SeeArticle9.4.2.2.)
4) Spans for roof ridge beams shall conform to the spans in Span Table9.23.4.2.-L for the uniform snow load
shown. (SeeArticles9.4.2.2. and9.23.14.8.)
9.23.4.3. Steel Beams
1) The spans for steel floor beams with laterally supported top flanges shall conform to Table9.23.4.3.
(SeeNoteA-9.23.4.3.(1).)
2) Beams described in Sentence(1) shall at least meet the requirements for Grade350W steel contained in
CSAG40.21, “Structural Quality Steel.”
9.23.4.4. Concrete Topping
(SeeNoteA-9.23.4.4.)
Table 9.23.4.3.
Maximum Spans for Steel Beams Supporting Floors in Dwelling Units
(1)
Forming Part of Sentence 9.23.4.3.(1)
Section
Supported Joist Length,m (half the sum of joist spans on both sides of the beam)
2.4 3.0 3.6 4.2 4.8 5.4 6.0
One Storey Supported
W150 × 22 5.5 5.2 4.9 4.8 4.6 4.5 4.3
W200 × 21 6.5 6.2 5.9 5.7 5.4 5.1 4.9
W200 × 27 7.3 6.9 6.6 6.3 6.1 5.9 5.8
W200 × 31 7.8 7.4 7.1 6.8 6.6 6.4 6.2
W250 × 24 8.1 7.6 7.3 7.0 6.6 6.2 5.9
W250 × 33 9.2 8.7 8.3 8.0 7.7 7.5 7.3
W250 × 39 10.0 9.4 9.0 8.6 8.4 8.1 7.9
W310 × 31 10.4 9.8 9.4 8.9 8.4 8.0 7.6
W310 × 39 11.4 10.7 10.2 9.8 9.5 9.2 9.0
Two
Storeys Supported
W150 × 22 4.9 4.4 4.1 3.8 3.5 3.4 3.2
W200 × 21 5.6 5.1 4.6 4.3 4.1 3.8 3.7
W200 × 27 6.4 6.1 5.6 5.3 4.9 4.7 4.4
W200 × 31 6.9 6.5 6.2 5.8 5.4 5.1 4.9
W250 × 24 6.8 6.1 5.6 5.2 4.9 4.6 4.4
W250 × 33 8.2 7.7 7.0 6.5 6.1 5.8 5.5
W250 × 39 8.8 8.3 7.8 7.2 6.8 6.4 6.1
W310 × 31 8.7 7.8 7.2 6.7 6.2 5.9 5.6
W310 × 39 10.0 9.3 8.5 7.9 7.4 7.0 6.7
Notes to Table9.23.4.3.:
(1) See Note A-Table 9.23.4.3.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
1) Except as permitted in Sentence(2), where a floor is required to support a concrete topping, the joist spans
shown in Span Table9.23.4.2.-A or the spacing of the members shall be reduced to allow for the loads due to the
topping.
2) Where a floor is required to support a concrete topping, joist spans are permitted to be selected from Span
Table9.23.4.2.-B provided the concrete
a) is 38 to 51mm thick,
b) is normal weight,
c) is placed directly on the subflooring, and
d) has not less than 20MPa compressive strength after 28 days.
3) Where a floor is required to support a concrete topping not more than 51mm thick, the allowable beam
spans shown in Span Tables9.23.4.2.-H to9.23.4.2.-K shall be multiplied by 0.8 or the supported length of the
floor joists shall be reduced to allow for the loads due to the topping.
9.23.4.5. Heavy Roofing Materials
1) Where a roof is required to support an additional uniform dead load from roofing materials such as concrete
roofing tile, or materials other than as specified in Section9.27., such as clay roofing tiles, the additional load shall be
allowed for by reducing
a) the spans for roof joists and rafters in Span Tables9.23.4.2.-D to9.23.4.2.-G, or the spacing of the members,
and
b) the spans for ridge beams and lintels in Span Tables9.23.4.2.-L and9.23.12.3.-A to9.23.12.3.-D.
(SeeNoteA-9.23.4.2.)
9.23.5. Notching and Drilling
9.23.5.1. Holes Drilled in Framing Members
1) Holes drilled in roof, floor or ceiling framing members shall be not larger than one-quarter the depth of the
member and shall be located not less than 50mm from the edges, unless the depth of the member is increased by the
size of the hole.
9.23.5.2. Notching of Framing Members
1) Floor, roof and ceiling framing members are permitted to be notched provided the notch is located on the top
of the member within half the joist depth from the edge of bearing and is not deeper than one-third the joist depth,
unless the depth of the member is increased by the size of the notch.
9.23.5.3. Wall Studs
1) Wall studs shall not be notched, drilled or otherwise damaged so that the undamaged portion of the stud is
less than two-thirds the depth of the stud if the stud is loadbearing or 40mm if the stud is non-loadbearing, unless the
weakened studs are suitably reinforced.
9.23.5.4. Top Plates
1) Top plates in walls shall not be notched, drilled or otherwise weakened to reduce the undamaged width to less
than 50mm unless the weakened plates are suitably reinforced.
9.23.5.5. Roof Trusses
1) Roof truss members shall not be notched, drilled or otherwise weakened unless such notching or drilling is
allowed for in the design of the truss.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.23.6. Anchorage
9.23.6.1. Anchorage of Building Frames
1) Except as required by Sentence9.23.6.3.(1), building frames shall be anchored to the foundation unless a
structural analysis of wind and earthquake pressures shows anchorage is not required.
2) Except as provided in Sentences(3) to(6), anchorage shall be provided by
a) embedding the ends of the first floor joists in concrete, or
b) fastening the sill plate to the foundation with not less than 12.7mm diam anchor bolts spaced not more than
2.4 m o.c.
3) For buildings with 2 or more floors supported by frame walls that are in areas where the seismic spectral
response acceleration, S
a
(0.2), is not greater than 0.70 or the 1-in-50 hourly wind pressure (HWP) is equal to or
greater than 0.80kPa but not greater than 1.20kPa, anchorage shall be provided by fastening the sill plate to the
foundation with not less than two anchor bolts per braced wall panel, where all anchor bolts used are
a) not less than 15.9mm in diameter, located within 0.5m of the end of the foundation, and spaced not more
than 2.4m o.c, or
b) not less than 12.7mm in diameter, located within 0.5m of the end of the foundation, and spaced not more
than 1.7m o.c.
4) For buildings supported by frame walls that are in areas where the seismic spectral response acceleration,
S
a
(0.2), is greater than 0.70 but not greater than 1.8 and the 1-in-50 hourly wind pressure (HWP) is not greater than
1.20kPa, anchorage shall be provided by fastening the sill plate to the foundation with not less than two anchor bolts
per braced wall panel located within 0.5m of the end of the foundation and spaced in accordance with Table9.23.6.1.
Table 9.23.6.1.
Anchor Bolt Spacing where the 1-in-50 HWP ≤ 1.20 kPa and 0.70 < S
a
(0.2) ≤ 1.8
Forming Part of Sentence 9.23.6.1.(4)
Anchor Bolt
Diameter, mm
S
a
(0.2)
Maximum Spacing of Anchor Bolts Along Braced Wall Band, m
Light Construction Heavy Construction
(1)
Number of Floors Supported
(2)
1 2 3 1 2
12.7 0.70 < S
a
(0.2) ≤ 0.80 2.4 2.3 1.8 2.4 2.0
0.80 < S
a
(0.2) ≤ 0.90 2.4 2.3 1.8 2.4 2.0
0.90 < S
a
(0.2) ≤ 1.0 2.4 2.2 1.5 2.4 1.8
1.0 < S
a
(0.2) ≤ 1.1 2.4 2.1 1.4 2.4 1.6
1.1 < S
a
(0.2) ≤ 1.2 2.4 2.0 1.3 2.4 1.5
1.2 < S
a
(0.2) ≤ 1.3 2.4 1.9 1.3 2.4 1.5
1.3 < S
a
(0.2) ≤ 1.35 2.4 1.8 1.2 2.3 1.4
1.35 < S
a
(0.2) ≤ 1.8 2.4 1.8 1.1 2.3 1.4
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
5) Anchor bolts referred to in Sentences(2) to(4) shall be
a) fastened to the sill plate with nuts and washers,
b) embedded not less than 100mm in the foundation, and
c) so designed that they may be tightened without withdrawing them from the foundation.
6) Where the seismic spectral response acceleration, S
a
(0.2), is greater than 1.8 or the 1-in-50 hourly wind
pressure is equal to or greater than 1.2kPa, anchorage shall be designed according to Part4.
9.23.6.2. Anchorage of Columns and Posts
1) Except as provided in Sentences(2) and(3), exterior columns and posts shall be anchored to resist uplift and
lateral movement.
2) Except as provided in Sentence(3), where columns or posts support balconies, decks, verandas or other
exterior platforms, and the distance from finished ground to the underside of the joists is not more than 600mm,
a) the columns or posts shall be anchored to the foundation to resist uplift and lateral movement, or
b) the supported joists or beams shall be directly anchored to the ground to resist uplift.
3) Anchorage is not required for platforms described in Sentence(2) that
a) are not more than 1 storey in height,
b) are not more than 55m
2
in area,
c) do not support a roof, and
d) are not attached to another structure, unless it can be demonstrated that differential movement will not
adversely affect the performance of the structure to which the platform is attached.
9.23.6.3. Anchorage of Smaller Buildings
1) Buildings not more than 4.3m wide and not more than 1 storey in building height that are not anchored in
accordance with Sentence9.23.6.1.(1) shall be anchored in conformance with the requirements of CSAZ240.10.1,
“Site Preparation, Foundation, and Anchorage of Manufactured Homes.”
15.9 0.70 < S
a
(0.2) ≤ 0.80 2.4 2.4 2.2 2.4 2.4
0.80 < S
a
(0.2) ≤ 0.90 2.4 2.4 2.2 2.4 2.4
0.90 < S
a
(0.2) ≤ 1.0 2.4 2.4 2.1 2.4 2.3
1.0 < S
a
(0.2) ≤ 1.1 2.4 2.4 1.9 2.4 2.3
1.1 < S
a
(0.2) ≤ 1.2 2.4 2.4 1.9 2.4 2.2
1.2 < S
a
(0.2) ≤ 1.3 2.4 2.4 1.8 2.4 2.1
1.3 < S
a
(0.2) ≤ 1.35 2.4 2.3 1.7 2.4 2.0
1.35 < S
a
(0.2) ≤ 1.8 2.4 2.2 1.6 2.4 1.9
Notes to Table9.23.6.1.:
(1) See Note A-9.23.13.2.(1)(a)(i).
(2) All constructions include support of a roof load in addition to the indicated number of floors.
Table 9.23.6.1. (continued)
Anchor Bolt Spacing where the 1-in-50 HWP ≤ 1.20 kPa and 0.70 < S
a
(0.2) ≤ 1.8
Forming Part of Sentence 9.23.6.1.(4)
Anchor Bolt
Diameter, mm
S
a
(0.2)
Maximum Spacing of Anchor Bolts Along Braced Wall Band, m
Light Construction Heavy Construction
(1)
Number of Floors Supported
(2)
1 2 3 1 2
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.23.7. Sill Plates
9.23.7.1. Size of Sill Plates
1) Where sill plates provide bearing for the floor system, they shall be not less than 38mm by 89mm material.
9.23.7.2. Levelling and Sealing of Sill Plates
1) Sill plates shall be
a) levelled by setting them on a full bed of mortar, or
b) laid directly on the foundation if the top of the foundation is level.
(Seealso Article9.23.2.3.)
2) The joint between the sill plate for exterior walls and the foundation shall be sealed in accordance with
Subsection9.25.3.
9.23.8. Beams to Support Floors
9.23.8.1. Bearing for Beams
1) Beams shall have even and level bearing and the bearing at end supports shall be not less than 89mm long,
except as stated in the notes to Span Tables9.23.4.2.-H to9.23.4.2.-K.
9.23.8.2. Priming of Steel Beams
1) Exterior steel beams shall be shop primed.
9.23.8.3. Built-up Wood Beams
(SeeNoteA-9.23.8.3.)
1) Where a beam is made up of individual pieces of lumber that are nailed together, the individual members
shall be 38mm or greater in thickness and installed on edge.
2) Except as permitted in Sentence(3), where individual members of a built-up beam are butted together to
form a joint, the joint shall occur over a support.
3) Where a beam is continuous over more than one span, individual members are permitted to be butted
together to form a joint at or within 150mm of the end quarter points of the clear spans, provided the quarter points
are not those closest to the ends of the beam.
4) Members joined at quarter points shall be continuous over adjacent supports.
5) Joints in individual members of a beam that are located at or near the end quarter points shall not occur in
adjacent members at the same quarter point and shall not reduce the effective beam width by more than half.
6) Not more than one butt joint shall occur in any individual member of a built-up beam within any one span.
7) Except as provided in Sentence(8), where 38mm members are laid on edge to form a built-up beam,
individual members shall be nailed together with a double row of nails not less than 89mm in length, spaced not
more than 450mm apart in each row with the end nails located 100mm to 150mm from the end of each piece.
8) Where 38mm members in built-up wood beams are not nailed together as provided in Sentence(7), they
shall be bolted together with not less than 12.7mm diam bolts equipped with washers and spaced not more than
1.2m o.c., with the end bolts located not more than 600mm from the ends of the members.
9.23.9. Floor Joists
9.23.9.1. End Bearing for Joists
1) Except when supported on ribbon boards, floor joists shall have not less than 38mm length of end bearing.
2) Ribbon boards referred to in Sentence(1) shall be not less than 19mm by 89mm lumber let into the studs.
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British Columbia Building Code 2018 Division B
9.23.9.2. Joists Supported by Beams
1) Floor joists may be supported on the tops of beams or may be framed into the sides of beams.
2) When framed into the side of a wood beam, joists referred to in Sentence(1) shall be supported on
a) joist hangers or other acceptable mechanical connectors, or
b) not less than 38mm by 64mm ledger strips nailed to the side of the beam, except that 38mm by 38mm
ledger strips may be used provided each joist is nailed to the beam by not less than four 89mm nails, in
addition to the nailing for the ledger strip required in Table9.23.3.4.
3) When framed into the side of a steel beam, joists referred to in Sentence(1) shall be supported on the bottom
flange of the beam or on not less than 38mm by 38mm lumber bolted to the web with not less than 6.3mm diam
bolts spaced not more than 600mm apart.
4) Joists referred to in Sentence(3) shall be spliced above the beam with not less than 38mm by 38mm lumber
at least 600mm long to support the flooring.
5) Not less than a 12mm space shall be provided between the splice required in Sentence(4) and the beam to
allow for shrinkage of the wood joists.
9.23.9.3. Restraint of Joist Bottoms
1) Except as provided in Sentence9.23.9.4.(1), bottoms of floor joists shall be restrained from twisting at each
end by toe-nailing to the supports, end-nailing to the header joists or by providing continuous strapping, blocking
between the joists or cross-bridging near the supports.
9.23.9.4. Strapping, Bridging, Furring and Ceilings in Span Tables 9.23.4.2.-A and -B
(SeeNoteA-9.23.4.2.(2).)
1) Except as permitted by Sentence(5), where strapping is specified in Span Table9.23.4.2.-A, it shall be
a) not less than 19mm by 64 mm, nailed to the underside of floor joists,
b) located not more than 2 100mm from each support or other rows of strapping, and
c) fastened at each end to a sill or header.
2) Where bridging is specified in Span Table9.23.4.2.-A, it shall consist of not less than 19mm by 64mm or
38mm by 38mm cross bridging located not more than 2 100mm from each support or other rows of bridging.
3) Where bridging and strapping are specified in Span Table9.23.4.2.-A,
a) bridging shall
i) comply with Sentence(2), or
ii) consist of 38mm solid blocking located not more than 2 100mm from each support or other rows of
bridging and securely fastened between the joists, and
b) except as provided in Sentence(5), strapping shall comply with Sentence(1) and be installed under
the bridging.
4) Bridging specified in Span Table9.23.4.2.-B shall consist of
a) bridging as described in Sentence(2), or
b) 38mm solid blocking located not more than 2 100mm from each support or other rows of bridging and
securely fastened between the joists.
5) Strapping described in Sentence(1) and Clause(3)(b) is not required where
a) furring strips complying with Table9.29.3.1. are fastened directly to the joists, or
b) a panel-type ceiling finish complying with Subsection9.29.5., 9.29.6., 9.29.7., 9.29.8., or 9.29.9. is attached
directly to the joists.
6) Where a ceiling attached to wood furring is specified in Span Table9.23.4.2.-B,
a) the ceiling finish shall consist of gypsum board, plywood or OSB not less than 12.7mm thick, and
b) the furring shall be
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
i) 19mm by 89mm wood furring spaced at not more than 600mm o.c., or
ii) 19mm by 64mm wood furring spaced at not more than 400mm o.c.
9.23.9.5. Header Joists
1) Header joists around floor openings shall be doubled when they exceed 1.2m in length.
2) The size of header joists exceeding 3.2m in length shall be determined by calculations.
9.23.9.6. Trimmer Joists
1) Trimmer joists around floor openings shall be doubled when the length of the header joist exceeds 800mm.
2) When the header joist exceeds 2m in length the size of the trimmer joists shall be determined by calculations.
9.23.9.7. Support of Tail and Header Joists
1) When tail joists and header joists are supported by the floor framing, they shall be supported by suitable joist
hangers or nailing in accordance with Table9.23.3.4.
9.23.9.8. Support of Walls
1) Non-loadbearing walls parallel to the floor joists shall be supported by joists beneath the wall or on blocking
between the joists.
2) Blocking referred to in Sentence(1) for the support of non-loadbearing walls shall be
a) not less than 38mm by 89mm lumber, and
b) except as required for the fastening of walls constructed with required braced wall panels, spaced not more
than 1.2m apart.
3) Except as provided in Sentence(6), non-loadbearing interior walls at right angles to the floor joists are not
restricted as to location.
4) Loadbearing interior walls parallel to floor joists shall be supported by beams or walls of sufficient strength to
safely transfer the specified live loads to the vertical supports.
5) Unless the joist size is designed to support such loads, loadbearing interior walls at right angles to floor joists
shall be located
a) not more than 900mm from the joist support where the wall does not support a floor, and
b) not more than 600mm from the joist support where the wall supports one or more floors.
6) Loadbearing and non-loadbearing walls constructed with required braced wall panels shall be continuously
supported by floor joists, blocking or rim joists to allow for the required fastening (seeTable9.23.3.4.).
9.23.9.9. Cantilevered Floor Joists
1) Floor joists supporting roof loads shall not be cantilevered more than 400mm beyond their supports where
38mm by 184mm joists are used and not more than 600mm beyond their supports where 38mm by 235mm or
larger joists are used.
2) The cantilevered portions referred to in Sentence(1) shall not support floor loads from other storeys unless
calculations are provided to show that the design resistances of the cantilevered joists are not exceeded.
3) Where cantilevered floor joists described in Sentences(1) and(2) are at right angles to the main floor joists,
thetail joists in the cantilevered portion shall extend inward away from the cantilever support a distance equal to not
less than 6 times the length of the cantilever, and shall be end nailed to an interior doubled header joist in
conformance with Table9.23.3.4.
9.23.10. Wall Studs
9.23.10.1. Stud Size and Spacing
1) The size and spacing of studs shall conform to Table9.23.10.1.
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British Columbia Building Code 2018 Division B
9.23.10.2. Bracing and Lateral Support
1) Where loadbearing interior walls are not finished in accordance with Section9.29., blocking or strapping shall
be fastened to the studs at mid-height to prevent sideways buckling.
9.23.10.3. Orientation of Studs
1) Except as permitted in Sentences(2) and(3), all studs shall be placed at right angles to the wall face.
2) Studs on the flat are permitted to be used in gable ends of roofs that contain only unfinished space or in
non-loadbearing interior walls within the limits described in Article9.23.10.1.
3) Wall studs that support only a load from an attic not accessible by a stairway are permitted to be placed on
the flat within the limits permitted in Article9.23.10.1. provided
Table 9.23.10.1.
Size and Spacing of Studs
Forming Part of Sentence 9.23.10.1.(1)
Type of Wall
Supported Loads
(including dead loads)
Minimum Stud Size, mm
Maximum Stud Spacing,
mm
(1)
Maximum Unsupported
Height, m
Interior
No load
38 × 38 400 2.4
38 × 89 flat
(2)
400 3.6
Attic not accessible by a stairway
38 × 64 600 3.0
38 × 64 flat
(2)
400 2.4
38 × 89 600 3.6
38 × 89 flat
(2)
400 2.4
Attic accessible by a stairway plus one floor
Roof load plus one floor
Attic not accessible by stairway plus 2 floors
38 × 89 400 3.6
Roof load
Attic accessible by a stairway
Attic not accessible by a stairway plus one floor
38 × 64 400 2.4
38 × 89 600 3.6
Attic accessible by a stairway plus 2 floors
Roof load plus 2 floors
38 × 89 300 3.6
64 × 89 400 3.6
38 × 140 400 4.2
Attic accessible by a stairway plus 3 floors
Roof load plus 3 floors
38 × 140 300 4.2
Exterior
Roof with or without attic storage
38 × 64 400 2.4
38 × 89 600 3.0
Roof with or without attic storage plus one floor
38 × 89 400 3.0
38 × 140 600 3.0
Roof with or without attic storage plus 2 floors
38 × 89 300 3.0
64 × 89 400 3.0
38 × 140 400 3.6
Roof with or without attic storage plus 3 floors 38 × 140 300 1.8
Notes to Table9.23.10.1.:
(1) See Note A-9.4.2.1.(1).
(2) See Article 9.23.10.3.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
a) the studs are clad on not less than one side with plywood, OSB or waferboard sheathing fastened to the face
of the studs with a structural adhesive, and
b) the portion of the roof supported by the studs does not exceed 2.1m in width.
9.23.10.4. Continuity of Studs
1) Wall studs shall be continuous for the full storey height except at openings and shall not be spliced except by
fingerjoining with a structural adhesive. (SeeNoteA-9.23.10.4.(1).)
9.23.10.5. Support for Cladding, Sheathing and Finishing Materials
1) Corners and intersections shall be designed to provide adequate support for the vertical edges of interior
finishes, sheathing and cladding materials, and in no instance shall exterior corners be framed with less than the
equivalent of 2studs.
2) Where the vertical edges of interior finishes at wall intersections are supported at vertical intervals by blocking
or furring, the vertical distance between such supports shall not exceed the maximum distance between supports
specified in Section9.29.
9.23.10.6. Studs at Sides of Openings
1) Where the lintel spanning the opening is more than 3m long, studs shall be tripled on each side of the
opening so that
a) the two inner studs on each side extend from the bottom of the supported lintel to the top of the bottom wall
plate, and
b) the outer stud on each side extends from the bottom of the top wall plate to the bottom wall plate.
2) Except as provided in Sentence(3), where the lintel spanning the opening is not more than 3m long, studs
shall be doubled on each side of the opening so that
a) the inner studs on each side extend from the bottom of the supported lintel to the top of the bottom wall
plate, and
b) the outer stud on each side extends from the bottom of the top wall plate to the bottom wall plate.
3) Single studs are permitted to be used on either side of openings
a) in non-loadbearing interior walls not required to have fire-resistance ratings, provided the studs extend from
the top wall plate to the bottom wall plate, or
b) in loadbearing or non-loadbearing interior or exterior walls, provided
i) the opening is less than and within the required stud spacing, and
ii) no 2 such openings of full stud-space width are located in adjacent stud spaces.
(SeeNoteA-9.23.10.6.(3).)
9.23.11. Wall Plates
9.23.11.1. Size of Wall Plates
1) Except as provided in Sentence(2), wall plates shall be
a) not less than 38mm thick, and
b) not less than the required width of the wall studs.
2) In non-loadbearing walls and in loadbearing walls where the studs are located directly over framing members,
the bottom wall plate is permitted to be 19mm thick.
9.23.11.2. Bottom Wall Plates
1) A bottom wall plate shall be provided in all cases.
2) The bottom plate in exterior walls shall not project more than one-third the plate width over the support.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.23.11.3. Top Plates
1) Except as permitted in Sentences(2) to(4), at least 2 top plates shall be provided in loadbearing walls.
2) A single top plate is permitted to be used in a section of a loadbearing wall containing a lintel provided the top
plate forms a tie across the lintel.
3) A single top plate is permitted to be used in loadbearing walls where the concentrated loads from ceilings,
floors and roofs are not more than 50mm to one side of the supporting studs and in all non-loadbearing walls.
4) The top plates need not be provided in a section of loadbearing wall containing a lintel provided the lintel is
tied to the adjacent wall section with not less than
a) 75mm by 150mm by 0.91mm thick galvanized steel, or
b) 19mm by 89mm by 300mm wood splice nailed to each wall section with at least three 63mm nails.
9.23.11.4. Joints in Top Plates
1) Joints in the top plates of loadbearing walls shall be staggered not less than one stud spacing.
2) The top plates in loadbearing walls shall be lapped or otherwise tied at corners and intersecting walls in
accordance with Sentence(4).
3) Joints in single top plates used with loadbearing walls shall be tied in accordance with Sentence(4).
4) Ties referred to in Sentences(2) and(3) shall be the equivalent of not less than 75mm by 150mm by
0.91mm thick galvanized steel nailed to each wall with at least three 63mm nails.
5) Where the seismic spectral response acceleration, S
a
(0.2), is greater than 0.70 but not more than 1.8, doubled
top plates in braced wall bands shall be fastened on each side of a splice with 76mm long common steel wire nails or
spiral nails in accordance with Table9.23.11.4.
9.23.12. Framing over Openings
9.23.12.1. Openings in Non-Loadbearing Walls
1) Except as provided in Sentence(2), openings in non-loadbearing walls shall be framed with not less than
38mm material the same width as the studs, securely nailed to adjacent studs.
Table 9.23.11.4.
Fasteners in Doubled Top Plate Splice Connections in Braced Wall Bands where 0.70 < S
a
(0.2) ≤ 1.8
Forming Part of Sentence 9.23.11.4.(5)
S
a
(0.2)
Minimum Number of Nails on Each Side of Doubled Top Plate Splice
Light Construction Heavy Construction
(1)
Number of Supported Floors
(2)
01201
0.70 < S
a
(0.2) ≤ 0.8025838
0.80 < S
a
(0.2) ≤ 0.9025848
0.90 < S
a
(0.2) ≤ 1.03 610410
1.0 < S
a
(0.2) ≤ 1.13 711511
1.1 < S
a
(0.2) ≤ 1.23 711512
1.2 < S
a
(0.2) ≤ 1.33 812512
1.3 < S
a
(0.2) ≤ 1.35 4 8 12 5 13
1.35 < S
a
(0.2) ≤ 1.84 813513
Notes to Table9.23.11.4.:
(1) See Note A-9.23.13.2.(1)(a)(i).
(2) All constructions include support of a roof load in addition to the number of floors indicated.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Openings for doors in non-loadbearing walls required to be fire separations with a fire-resistance rating shall be
framed with the equivalent of at least two 38mm thick members that are the same width as the wall plates.
9.23.12.2. Openings in Loadbearing Walls
1) Openings in loadbearing walls greater than the required stud spacing shall be framed with lintels designed to
carry the superimposed loads to adjacent studs. (SeeNoteA-9.23.10.6.(3).)
2) Except as provided in Sentence9.23.12.3.(2), where 2 or more members are used in lintels, they shall be
fastened together with not less than 82mm nails in a double row, with nails not more than 450mm apart in
each row.
3) Lintel members are permitted to be separated by filler pieces.
9.23.12.3. Lintel Spans and Sizes
1) Spans and sizes of wood lintels shall conform to the spans shown in Span Tables9.23.4.2.-L
and9.23.12.3.-A to9.23.12.3.-D
a) for buildings of residential occupancy,
b) where the wall studs exceed 38mm by 64mm in size,
c) where the spans of supported joists do not exceed 4.9m, and
d) where the spans of trusses do not exceed 9.8m.
2) In loadbearing exterior and interior walls of 38mm by 64mm framing members, lintels shall consist of
a) 64mm thick members on edge, or
b) 38mm thick and 19mm thick members fastened together with a double row of nails not less than 63mm
long and spaced not more than 450mm apart.
3) Lintels referred to in Sentence(2)
a) shall be not less than 50mm greater in depth than those shown in Span Tables9.23.4.2.-L and9.23.12.3.-A
to9.23.12.3.-D for the maximum spans shown, and
b) shall not exceed 2.24m in length.
9.23.13. Bracing to Resist Lateral Loads Due to Wind and Earthquake
(SeeNoteA-9.23.13.)
9.23.13.1. Requirements for Low to Moderate Wind and Seismic Forces
(SeeNoteA-9.23.13.1.)
1) This Article applies in locations where the seismic spectral response acceleration, S
a
(0.2), is not more than
0.70 and the 1-in-50 hourly wind pressure is less than 0.80kPa.
2) Bracing to resist lateral loads shall be designed and constructed as follows:
a) exterior walls shall be
i) clad with panel-type cladding in accordance with Section9.27.,
ii) sheathed with plywood, OSB, waferboard, fibreboard, gypsum board or diagonal lumber sheathing
complying with Subsection9.23.17
. and fastened in accordance with Table9.23.3.5.-A, or
iii) finished on the interior with a panel-type material in accordance with the requirements of
Section9.29., or
b) in accordance with
i) Articles9.23.13.4. to9.23.13.7.,
ii) Part4, or
iii) good engineering practice such as that provided in CWC2014, “Engineering Guide for Wood Frame
Construction.”
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.23.13.2. Requirements for High Wind and Seismic Forces
1) Except as provided in Article9.23.13.1., this Article applies in locations where
a) the seismic spectral response acceleration, S
a
(0.2), is greater than 0.70 but not more than 1.8 and
i) the lowest exterior frame wall supports not more than 1floor in buildings of heavy construction
(seeNoteA-9.23.13.2.(1)(a)(i)), or
ii) the lowest exterior frame wall supports not more than 2floors in other types of construction, and
b) the 1-in-50 hourly wind pressure is less than 1.20kPa.
2) Bracing to resist lateral loads shall be designed and constructed in accordance with
a) Articles9.23.13.4. to9.23.13.7.,
b) Part4, or
c) good engineering practice such as that provided in CWC2014, “Engineering Guide for Wood Frame
Construction.”
9.23.13.3. Requirements for Extreme Wind and Seismic Forces
1) Except as provided in Articles9.23.13.1. and9.23.13.2., this Article applies in locations where
a) the seismic spectral response acceleration, S
a
(0.2), is
i) greater than 1.8,
ii) greater than 0.70 and the lowest exterior frame wall supports more than 2floors in buildings of light
construction, or
iii) greater than 0.70 and the lowest exterior frame wall supports more than 1floor in buildings of heavy
construction, or
b) the 1-in-50 hourly wind pressure is equal to or greater than 1.20kPa.
2) Bracing to resist lateral loads shall be designed and constructed in accordance with
a) Part4, or
b) good engineering practice such as that provided in CWC2014, “Engineering Guide for Wood Frame
Construction.”
9.23.13.4. Braced Wall Bands
(SeeNoteA-9.23.13.4.)
1) Braced wall bands shall
a) be full storey height,
b) be not more than 1.2m wide,
c) lap at both ends with another braced wall band,
d) be aligned with braced wall bands on storeys above and below, and
e) conform to the spacing and dimensions given in Table9.23.13.5.
2) The perimeter of the building shall be located within braced wall bands.
3) For split-level buildings, a braced wall band shall be located where there is a change in floor level greater than
the depth of one floor joist.
9.23.13.5. Braced Wall Panels in Braced Wall Bands
1) Except as provided in Sentences(2) to(5) and Article9.23.13.7., braced wall panels shall
a) be located within braced wall bands,
b) extend, as applicable, from the top of the supporting footing, slab or subfloor to the underside of the floor,
ceiling or roof framing above, and
c) conform to the spacing and dimensions given in Table9.23.13.5.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) In basements or crawl spaces where the perimeter foundation walls extend from the footings to the underside
of the supported floor, braced wall bands constructed with braced wall panels shall be spaced not more than
a) 15m from the perimeter foundation walls,
b) 15m from interior foundation walls, and
c) 15m from adjacent braced wall bands constructed with braced wall panels.
(SeeNoteA-9.23.13.5.(2).)
3) Portions of the perimeter of a single open or enclosed space need not comply with Sentence(1), where
a) the roof of the space projects not more than
i) 3.5m from the face of the framing of the nearest parallel braced wall band, and
ii) half the perpendicular plan dimension,
b) that portion of the perimeter structure does not support a floor, and
c) the roof of the space is
i) integral with the roof of the rest of the building with framing members not more than 400mm o.c., or
Table 9.23.13.5.
Spacing and Dimensions of Braced Wall Bands and Braced Wall Panels
Forming Part of Sentences 9.23.13.4.(1) and 9.23.13.5.(1)
Description
Spacing and Dimensions of Braced Wall Bands and
Braced Wall Panels
(1)(2)(3)
Seismic and Wind Loads
0.70 < S
a
(0.2) < 1.0
1.0 ≤ S
a
(0.2) ≤ 1.8 or
0.80 ≤ HWP < 1.2kPa
Maximum distance between centre lines of adjacent braced wall bands measured
from the furthest points between centres of the bands
10.6 m 7.6 m
Maximum distance between required braced wall panels measured from the edges of
the panels
6.4 m 6.4 m
Maximum distance from the end of a braced wall band to the edge of the closest
required braced wall panel
2.4 m 2.4 m
Minimum length of individual braced wall panels:
• panel located at the end of a braced wall band where the braced wall panel
connects to an intersecting braced wall panel
600 mm
• panel not located at the end of a braced wall band or braced wall panel located at
the end of a braced wall band where the braced wall panel does not connect to an
intersecting braced wall panel
750 mm
Minimum total length of all braced wall panels in a braced wall band
• supporting 3 floors, light construction 75% of length of braced wall band
• supporting 2 floors, heavy construction
(4)
75% of length of braced wall band
• supporting 2 floors, light construction 40% of length of braced wall band
• supporting 1 floor, heavy construction
(4)
40% of length of braced wall band
• supporting 1 floor, light construction 25% of length of braced wall band
• not supporting a floor 25% of length of braced wall band
Notes to Table9.23.13.5.:
(1) See Note A-Table 9.23.13.5.
(2) All constructions include support of a roof load in addition to the indicated number of floors.
(3) See Article 9.23.13.7. for alternative methods of compliance.
(4) See Sentence 9.23.13.3.(1) for overall limit on application to heavy construction.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
ii) constructed with roof framing not more than 400mm o.c. fastened to the wall framing
(seeTable9.23.3.4. and Article9.23.9.1. for balloon framing).
(SeeNoteA-9.23.13.5.(3).)
4) Walls in detached garages and in accessory buildings serving a single dwelling unit, and the front wall of
attached garages serving a single dwelling unit need not comply with Sentence(1) where these walls do not support
a floor.
5) Braced wall panels in the braced wall band at the front of an attached garage serving a single dwelling unit need
not comply with Sentence(1), provided
a) the maximum spacing between the front of the garage and the back wall of the garage does not exceed 7.6m,
b) there is not more than one floor above the garage,
c) not less than 50% of the length of the back wall of the garage is constructed of braced wall panels, and
d) not less than 25% of the length of the side walls is constructed of braced wall panels.
9.23.13.6. Materials in Braced Wall Panels
1) Required braced wall panels shall be
a) clad with panel-type cladding complying with Section9.27. and Table9.23.3.4.,
b) sheathed with plywood, OSB, waferboard or diagonal lumber sheathing complying with Subsection9.23.17
.
and Table9.23.13.6., and fastened in accordance with Article9.23.3.5., or
c) finished on the interior with a panel-type material in accordance with the requirements of Section9.29. and
Table9.23.13.6.
2) Except as provided in Sentence(3), required interior braced wall panels shall be
a) sheathed or finished on both sides with a wood-based material, or
b) finished on both sides with gypsum board.
3) Required interior braced wall panels of wood-based material may be sheathed on one side only, provided
a) the sheathing material is plywood, OSB or waferboard, and
b) the maximum spacing of fasteners along the edge is half of the maximum spacing shown in
Table9.23.3.5.-B.
4) For stacked braced wall bands, where the construction of any one braced wall panel is required to be of a
wood-based material, a wood-based material shall be installed in all the required braced wall panels in that braced
wall band.
Table 9.23.13.6.
Minimum Thicknesses of Cladding, Sheathing or Interior Finish for Braced Wall Panels
Forming Part of Sentence 9.23.13.6.(1)
Panel-TypeCladding,
Sheathing or Interior Finish
Minimum Thickness
Where S
a
(0.2) ≤ 0.90 Where S
a
(0.2) > 0.90
With supports 400mm o.c. With supports 600mm o.c. With supports 400mm o.c. With supports 600mm o.c.
Gypsum board interior finish
(1)
12.7 mm 15.9 mm 12.7 mm 15.9 mm
Sheathing complying with
CSA O325
W16 W24 W16 W24
OSB O-1 and O-2 grades 11 mm 12.5 mm 11 mm 12.5 mm
Waferboard R-1 grade 9.5 mm 12.5 mm n/a n/a
Plywood 11 mm 12.5 mm 11 mm 12.5 mm
Diagonal lumber 17 mm 17 mm n/a n/a
Notes to Table9.23.13.6.:
(1) See Sentences (5) and (6).
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
5) Gypsum board interior finish shall not be considered as an acceptable sheathing material to provide the
required bracing in exterior walls. (SeeNoteA-9.23.13.6.(5) and (6).)
6) At braced wall band spacing intervals of not more than 15m, braced wall panels shall be constructed with
OSB, plywood or diagonal lumber. (SeeNoteA-9.23.13.6.(5) and (6).)
9.23.13.7. Additional System Considerations
1) Except as provided in Sentences(2) and(3), one exterior wall of the uppermost storey in each orthogonal
direction may be set back from the exterior wall of the storey below, provided the adjacent interior braced wall band of
the storey below the setback
a) is spaced not more than 10.6m from the exterior wall of the storey below the setback wall,
b) consists of braced wall panels that are constructed of a wood-based material in conformance with
Sentence9.23.13.6.(2),
c) extends to the foundation, and
d) is not taken into consideration when providing braced wall panels constructed of a wood-based material at
spacing intervals of not more than 15m as per Sentence9.23.13.6.(6).
2) Where the exterior wall of the uppermost storey is set back from the exterior wall of the storey below, the roof
and floor space supporting the setback wall shall be sheathed with a wood-based material between the exterior wall of
the storey below the setback and the adjacent interior braced wall bands of the storey below the setback.
3) Where the exterior wall of the uppermost storey is set back from the exterior wall of the storey below, the
exterior walls perpendicular to the setback wall shall
a) have their top plate connected with nails that are spaced at no greater than half the spacing required in
Table9.23.3.4., and
b) have their top plate splices fastened with twice the number of nails specified in Sentences9.23.11.4.(4)
and(5).
4) The maximum distance between adjacent required braced wall panels in a braced wall band, measured from
the edge of the panels, may be increased to 7.3m provided that, throughout the height of the building, the length of
any braced wall panel within the braced wall band is not less than 1.2m.
5) The maximum spacing between the centre lines of required braced wall bands given in Table9.23.13.5. may
be increased from 7.6m to no more than 10.6m, provided that the interior braced wall band whose spacing is being
increased is replaced with an interior braced wall band
that
a) consists of braced wall panels that are constructed of a wood-based material in conformance with
Sentence9.23.13.6.(2),
b) extends to the foundation, and
c) is not taken into consideration when providing braced wall panels constructed of a wood-based material at
spacing intervals no greater than 15m as per Sentence9.23.13.6.(6).
6) For each orthogonal direction of the building, the length of required braced wall panels of one exterior wall
given in Table9.23.13.5. may be reduced from 40% to no less than 25% of the length of the braced wall band,
provided an additional parallel and adjacent interior braced wall band is constructed that
a) is spaced not more than 10.6m from the exterior wall,
b) consists of braced wall panels that are constructed of a wood-based material in conformance with
Sentence9.23.13.6.(2) and whose lengths sum to no less than 25% of the length of the braced wall band,
c) extends to the foundation, and
d) is not taken into consideration when providing braced wall panels constructed of a wood-based material at
spacing intervals no greater than 15m as per Sentence9.23.13.6.(6).
7) Where the length of required braced wall panels of an exterior wall is reduced as described in Sentence(6), the
ratio of the length of braced wall panels in the respective upper braced wall bands to the length of braced wall panels in
the reduced exterior braced wall band shall not exceed2.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.23.14. Roof and Ceiling Framing
9.23.14.1. Continuity of Rafters and Joists
1) Roof rafters and joists and ceiling joists shall be continuous or shall be spliced over vertical supports that
extend to suitable bearing.
9.23.14.2. Framing around Openings
1) Roof and ceiling framing members shall be doubled on each side of openings greater than2 rafter or joist
spacings wide.
9.23.14.3. End Bearing Length
1) The length of end bearing of joists and rafters shall be not less than 38mm.
9.23.14.4. Location and Attachment of Rafters
1) Rafters shall be located directly opposite each other and tied together at the peak, or may be offset by their
own thickness if nailed to a ridge board not less than 17.5mm thick.
2) Except as permitted in Sentence(3), framing members shall be connected by gusset plates or nailing at the
peak in conformance with Table9.23.3.4.
3) Where the roof framing on opposite sides of the peak is assembled separately, such as in the case of
factory-built houses, the roof framing on opposite sides is permitted to be fastened together with galvanized-steel
strips not less than 200mm by 75mm by 0.41mm thick spaced not more than 1.2m apart and nailed at each end to
the framing by atleast two 63mm nails.
9.23.14.5. Shaping of Rafters
1) Rafters shall be shaped at supports to provide even bearing surfaces and supported directly above the
exterior walls.
9.23.14.6. Hip and Valley Rafters
1) Hip and valley rafters shall be not less than 50mm greater in depth than the common rafters and not less
than 38mm thick, actual dimension.
9.23.14.7. Intermediate Support for Rafters and Joists
1) Ceiling joists and collar ties of not less than 38mm by 89mm lumber are permitted to be assumed to provide
intermediate support to reduce the span for rafters and joists where the roof slope is 1in3 or greater.
2) Collar ties referred to in Sentence(1) more than 2.4m long shall be laterally supported near their centres by
not less than 19mm by 89mm continuous members at right angles to the collar ties.
3) Dwarf walls and struts are permitted to be used to provide intermediate support to reduce the span for rafters
and joists.
4) When struts are used to provide intermediate support they shall be not less than 38mm by 89mm material
extending from each rafter to a loadbearing wall at an angle of not less than 45° to the horizontal.
5) When dwarf walls are used for rafter support, they shall be framed in the same manner as loadbearing walls
and securely fastened top and bottom to the roof and ceiling framing to prevent over-all movement.
6) Solid blocking shall be installed between floor joists beneath dwarf walls referred to in Sentence(5) that
enclose finished rooms.
9.23.14.8. Ridge Support
1) Except as provided in Sentence(4), roof rafters and joists shall be supported at the ridge of the roof by
a) a loadbearing wall extending from the ridge to suitable bearing, or
b) a ridge beam supported by not less than 89mm length of bearing.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Except as provided in Sentence(3), the ridge beam referred to in Sentence(1) shall conform to the sizes and
spans shown in Span Table9.23.4.2.-L, provided
a) the supported rafter or joist length does not exceed 4.9m, and
b) the roof does not support any concentrated loads.
3) The ridge beam referred to in Sentence(1) need not comply with Sentence(2) where
a) the beam is of not less than 38mm by 140mm material, and
b) the beam is supported at intervals not exceeding 1.2m by not less than 38mm by 89mm members
extending vertically from the ridge to suitable bearing.
4) When the roof slope is 1 in 3 or more, ridge support need not be provided when the lower ends of the rafters
are adequately tied to prevent outward movement.
5) Ties required in Sentence(4) are permitted to consist of tie rods or ceiling joists forming a continuous tie for
opposing rafters and nailed in accordance with Table9.23.14.8.
6) Ceiling joists referred to in Sentence(5) shall be fastened together with at least one more nail per joist splice
than required for the rafter to joist connection shown in Table9.23.14.8.
7) Members referred to in Sentence(6) are permitted to be fastened together either directly or through a
gusset plate.
9.23.14.9. Restraint of Joist Bottoms
1) Roof joists supporting a finished ceiling, other than plywood, OSB or waferboard, shall be restrained from
twisting along the bottom edges by means of furring, blocking, cross bridging or strapping conforming to
Article9.23.9.3.
Table 9.23.14.8.
Rafter-to-Joist Nailing (Unsupported Ridge)
Forming Part of Sentences 9.23.14.8.(5) and (6)
Roof
Slope
Rafter
Spacing,
mm
Minimum Number of Nails not less than 76mm Long
Rafter Tied to every Joist Rafter Tied to Joist every 1.2m
Building Width up to 8m Building Width up to 9.8m Building Width up to 8m Building Width up to 9.8m
Roof Snow Load,kPa Roof Snow Load,kPa Roof Snow Load,kPa Roof Snow Load,kPa
1.0 or
less
1.5
2.0 or
more
1.0 or
less
1.5
2.0 or
more
1.0 or
less
1.5
2.0 or
more
1.0 or
less
1.5
2.0 or
more
1 in 3
40045657811–––––
6006898––11–––––
1 in 2.4
400445567710–9––
6005787911710––––
1 in 2
4004444456898––
6004565786898––
1 in 1.71
4004444445787911
6004455675787911
1 in 1.33
400444444456567
600444445456567
1 in 1
400444444444445
600444444444445
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.23.14.10. Ceiling Joists Supporting Roof Load
1) Except as permitted in Sentence(2), ceiling joists supporting part of the roof load from the rafters shall be not
less than 25mm greater in depth than required for ceiling joists not supporting part of the roof load.
2) When the roof slope is 1 in 4 or less, the ceiling joist sizes referred to in Sentence(1) shall be determined from
Span Tables9.23.4.2.-C to9.23.4.2.-F and9.23.4.2.-L for roof joists.
9.23.14.11. Roof Trusses
1) Roof trusses which are not designed in accordance with Part4 shall
a) be capable of supporting a total ceiling load (dead load plus live load) of 0.35kPa plus two and two-thirds
times the specified live roof load for 24h, and
b) not exceed the deflections shown in Table9.23.14.11. when loaded with the ceiling load plus one and
one-third times the specified roof snow load for 1h.
2) The joint connections used in trusses described in Sentence(1) shall be designed in conformance with the
requirements in Subsection4.3.1. (SeeNoteA-9.23.14.11.(2).)
3) Where the length of compression web members in roof trusses described in Sentence(1) exceeds 1.83m,
such web members shall be provided with continuous bracing to prevent buckling.
4) Bracing required in Sentence(3) shall consist of not less than 19mm by 89mm lumber nailed at right angles
to the web members near their centres with at least two 63mm nails for each member.
5) Where the ability of a truss design to satisfy the requirements of Sentence(1) is demonstrated by testing,
it shall consist of a full scale load test carried out in conformance with CSAS307-M, “Load Test Procedure for Wood
Roof Trusses for Houses and Small Buildings.”
6) Where the ability of a truss design to satisfy the requirements of Sentence(1) is demonstrated by analysis,
it shall be carried out in accordance with good engineering practice such as that described in TPIC2014, “Truss
Design Procedures and Specifications for Light Metal Plate Connected Wood Trusses (Limit States Design).”
9.23.15. Subflooring
9.23.15.1. Subflooring Required
1) Subflooring shall be provided beneath finish flooring where the finish flooring does not have adequate
strength to support the specified live loads (seeSubsection9.30.3.).
9.23.15.2. Material Standards
1) Except as provided in Sentence(2), wood-based panels for subfloors shall conform to
a) CSAO121, “Douglas Fir Plywood,”
b) CSAO151, “Canadian Softwood Plywood,”
c) CSAO153, “Poplar Plywood,”
d) CSAO325, “Construction Sheathing,” or
e) CSAO437.0, “OSB and Waferboard.”
Table 9.23.14.11.
Maximum Roof Truss Deflections
Forming Part of Sentence 9.23.14.11.(1)
Truss Span Type of Ceiling Maximum Deflection
4.3 m or less
Plaster or gypsum board 1/360 of the span
Other than plaster or gypsum board 1/180 of the span
Over 4.3 m
Plaster or gypsum board 1/360 of the span
Other than plaster or gypsum board 1/240 of the span
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Particleboard subflooring may be used only where a building is constructed in a factory so that the subfloor
will not be exposed to the weather.
3) Subflooring described in Sentence(2) shall conform to grade D-2 or D-3 in ANSIA208.1, “Particleboard.”
4) Subflooring described in Sentence(2) shall have its upper surface and all edges treated to restrict water
absorption, where the subfloor is used in bathrooms, kitchens, laundry rooms or other areas subject to periodic
wetting. (SeeNoteA-9.23.15.2.(4).)
9.23.15.3. Edge Support
1) Where the edges of panel-type subflooring are required to be supported (seeSentence9.30.2.1.(2)), such
support shall consist of tongue-and-groove panel edges or not less than 38mm by 38mm blocking securely nailed
between framing members.
9.23.15.4. Direction of Installation
1) Plywood subflooring shall be installed with the surface grain at right angles to the joists and with joints
parallel to floor joists staggered.
2) OSB subflooring conforming to CSAO325, “Construction Sheathing,” or to O-1 and O-2 grades in
CSAO437.0, “OSB and Waferboard,” and waferboard subflooring conforming to R-1 grade in CSAO437.0 shall
be installed so that the direction of face orientation is at right angles to the joists and the joints parallel to the floor
joists are staggered. (SeeNoteA-9.23.15.4.(2).)
9.23.15.5. Subfloor Thickness or Rating
1) Except as provided in Sentences(2) and(3), subfloors shall conform to either Table9.23.15.5.-A
or9.23.15.5.-B.
2) Where the finished flooring consists of not less than 19mm matched wood strip flooring laid at right angles
to joists spaced not more than 600mm o.c., subflooring shall be permitted to consist of not less than
a) 12.5mm thick plywood,
b) 12.5mm thick OSB conforming to O-2 grade,
c) 12.7mm thick OSB conforming to O-1 grade,
d) 12.7mm thick waferboard conforming to R-1 grade, or
Table 9.23.15.5.-A
Thickness of Subflooring
Forming Part of Sentences 9.23.15.5.(1) and 9.23.16.7.(1)
Maximum Spacing of
Supports, mm
Minimum Thickness, mm
Plywood and OSB, O-2 Grade
OSB, O-1 Grade, and
Waferboard, R-1 Grade
Particleboard Lumber
400 15.5 15.9 15.9 17.0
500 15.5 15.9 19.0 19.0
600 18.5 19.0 25.4 19.0
Table 9.23.15.5.-B
Rating for Subfloor when Applying CSA O325
Forming Part of Sentences 9.23.15.5.(1) and 9.23.16.7.(1)
Maximum Spacing of Supports, mm
Panel Mark
Subfloor Used with Panel-TypeUnderlay
400 1F16 2F16
500 1F20 2F20
600 1F24 2F24
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
e) OSB conforming to 2R32/2F16 grade.
3) Except where the flooring consists of ceramic tiles applied with adhesive, where a separate panel-type
underlay or concrete topping is applied to a subfloor on joists spaced not more than 400mm o.c., the subfloor is
permitted to consist of not less than
a) 12.5mm thick plywood,
b) 12.5mm thick OSB conforming to O-2 grade,
c) 12.7mm thick OSB conforming to O-1 grade,
d) 12.7mm thick waferboard conforming to R-1 grade, or
e) OSB conforming to 2R32/2F16 grade.
9.23.15.6. Annular Grooved Nails
1) When resilient flooring is applied directly to an OSB, waferboard, particleboard or plywood subfloor, the
subfloor shall be fastened to the supports with annular grooved nails.
9.23.15.7. Lumber Subflooring
1) Lumber subflooring shall be laid at an angle of not less than 45° to the joists.
2) Lumber subflooring shall be fully supported at the ends on solid bearing.
3) Lumber for subflooring shall be of uniform thickness and not more than 184mm wide.
9.23.16. Roof Sheathing
9.23.16.1. Required Roof Sheathing
1) Except where the 1-in-50 hourly wind pressure is less than 0.8kPa and the seismic spectral response
acceleration, S
a
(0.2), is less than or equal to 0.70, continuous lumber or panel-type roof sheathing shall be installed to
support the roofing.
9.23.16.2. Material Standards
1) Wood-based panels used for roof sheathing shall conform to the requirements of
a) CSAO121, “Douglas Fir Plywood,”
b) CSAO151, “Canadian Softwood Plywood,”
c) CSAO153, “Poplar Plywood,”
d) CSAO325, “Construction Sheathing,” or
e) CSAO437.0, “OSB and Waferboard.”
9.23.16.3. Direction of Installation
1) Plywood roof sheathing shall be installed with the surface grain at right angles to the roof framing.
2) OSB roof sheathing conforming to CSAO325, “Construction Sheathing,” or to O-1 and O-2 grades as
specified in CSAO437.0, “OSB and Waferboard,” shall be installed with the direction of face orientation at right
angles to the roof framing members. (SeeNoteA-9.23.15.4.(2).)
9.23.16.4. Joints in Panel-TypeSheathing
1) Panel-type sheathing board shall be applied so that joints perpendicular to the roof ridge are staggered where
a) the sheathing is applied with the surface grain parallel to the roof ridge, and
b) the thickness of the sheathing is such that the edges are required to be supported.
2) A gap of not less than 2mm shall be left between sheets of plywood, OSB or waferboard.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.23.16.5. Lumber Roof Sheathing
1) Lumber roof sheathing shall not be more than 286mm wide and shall be applied so that all ends are
supported with end joints staggered.
2) Lumber roof sheathing shall be installed diagonally, where
a) the seismic spectral response acceleration, S
a
(0.2), is greater than 0.70 but not greater than 1.2, or
b) the 1-in-50 hourly wind pressure is equal to or greater than 0.80kPa but less than 1.20kPa.
3) Lumber roof sheathing shall be designed according to Part4, where
a) the seismic spectral response acceleration, S
a
(0.2), is greater than 1.2, or
b) the 1-in-50 hourly wind pressure is equal to or greater than 1.20kPa.
9.23.16.6. Edge Support
1) Where panel-type roof sheathing requires edge support, the support shall consist of metal Hclips or not less
than 38mm by 38mm blocking securely nailed between framing members.
9.23.16.7. Thickness or Rating
1) The thickness or rating of roof sheathing on a flat roof used as a walking deck shall conform to either
Table9.23.15.5.-A or Table9.23.15.5.-B for subfloors.
2) The thickness or rating of roof sheathing on a roof not used as a walking deck shall conform to either
Table9.23.16.7.-A or Table9.23.16.7.-B.
3) Asphalt-coated or asphalt-impregnated fibreboard not less than 11.1mm thick conforming to
CAN/ULC-S706, “Wood Fibre Insulating Boards for Buildings,” is permitted to be used as a roof sheathing over
supports spaced not more than 400mm o.c. provided the roofing consists of
a) a continuous sheet of galvanized steel not less than 0.33mm in thickness, or
b) a continuous sheet of aluminum not less than 0.61mm in thickness.
4) All edges of sheathing described in Sentence(3) shall be supported by blocking or framing.
Table 9.23.16.7.-A
Thickness of Roof Sheathing
Forming Part of Sentence 9.23.16.7.(2)
Maximum Spacing of
Supports, mm
Minimum Thickness, mm
Plywood, and OSB, O-2 Grade OSB, O-1 Grade, and Waferboard, R-1 Grade
Lumber
Edges Supported Edges Unsupported Edges Supported Edges Unsupported
300 7.5 7.5 9.5 9.5 17.0
400 7.5 9.5 9.5 11.1 17.0
600 9.5 12.5 11.1 12.7 19.0
Table 9.23.16.7.-B
Rating for Roof Sheathing When Applying CSA O325
Forming Part of Sentence 9.23.16.7.(2)
Maximum Spacing of Supports, mm
Panel Mark
Edges Supported Edges Unsupported
400 2R16 1R16
500 2R20 1R20
600 2R24 1R24
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.23.17. Wall Sheathing
9.23.17.1. Required Sheathing
1) Exterior walls and gable ends shall be sheathed when the exterior cladding requires intermediate fastening
between supports or if the exterior cladding requires solid backing.
9.23.17.2. Thickness, Rating and Material Standards
1) Where wall sheathing is required for the purpose of complying with this Section, it shall conform to either
Table9.23.17.2.-A or9.23.17.2.-B. (Seealso Article9.25.5.1.)
9.23.17.3. Attachment of Cladding to Sheathing
1) Gypsum sheathing, rigid insulation and fibreboard shall not be used for the attachment of cladding materials.
Table 9.23.17.2.-A
Wall Sheathing Thickness and Specifications
Forming Part of Sentence 9.23.17.2.(1)
Type of Sheathing
Minimum Thickness, mm
(1)
Material Standards
With Supports
400mm o.c.
With Supports
600mm o.c.
Fibreboard (insulating) 9.5 11.1 CAN/ULC-S706
Gypsum sheathing
9.5 12.7
ASTM C 1177/C 1177M
ASTM C 1396/C 1396M
(2)
Lumber 17.0 17.0 See Table 9.3.2.1.
Mineral Fibre, Rigid Board, Type 2 25 25 CAN/ULC-S702
OSB, O-2 Grade 6.0 7.5 CSA O437.0
OSB, O-1 Grade, and Waferboard, R-1 Grade 6.35 7.9 CSA O437.0
Phenolic, faced 25 25 CAN/CGSB-51.25-M
Plywood (exterior type)
6.0 7.5
CSA O121
CSA O151
CSA O153
Polystyrene, Types 1 and 2 38 38 CAN/ULC-S701
Polystyrene, Types 3 and 4 25 25 CAN/ULC-S701
Polyurethane and Polyisocyanurate Type 1, faced 38 38 CAN/ULC-S704
Polyurethane and Polyisocyanurate Types 2 and 3, faced 25 25 CAN/ULC-S704
Notes to Table9.23.17.2.-A:
(1) See also Sentences 9.27.5.1.(2) to (4).
(2) The flame-spread rating of gypsum board shall be determined in accordance with CAN/ULC-S102, “Test for Surface Burning Characteristics of Building Materials and
Assemblies.”
Table 9.23.17.2.-B
Rating for Wall Sheathing when Applying CSA O325
Forming Part of Sentence 9.23.17.2.(1)
Maximum Spacing of Supports, mm Panel Mark
400 W16
500 W20
600 W24
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.23.17.4. Lumber Sheathing
1) Lumber wall sheathing shall be applied so that all ends are supported.
2) Where lumber wall sheathing is required to provide bracing according to Article9.23.10.2., it shall be applied
with end joints staggered.
9.23.17.5. Joints in Panel-TypeSheathing
1) A gap of not less than 2mm shall be left between sheets of plywood, OSB, waferboard or fibreboard.
9.23.17.6. Mansard Style Roofs
1) Where the bottom portions of mansard style roofs are vented, the vertical framing members behind the
sloping portions shall be considered on the same basis as exterior wall studs and shall conform to Articles9.27.3.2.
to9.27.3.6.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.24. Sheet Steel Stud Wall Framing
9.24.1. General
9.24.1.1. Application
1) This Section applies to sheet steel studs for use in non-loadbearing exterior and interior walls.
2) Where loadbearing steel studs are used, they shall be designed in conformance with Part4.
9.24.1.2. Material Standards
1) Steel studs and runners shall conform to AISI S201, “North American Standard for Cold-Formed Steel
Framing – Product Data.”
9.24.1.3. Metal Thickness
1) Metal thickness specified in this Section shall be the minimum base steel thickness exclusive of coatings.
9.24.1.4. Screws
1) Screws for the application of cladding, sheathing or interior finish materials to steel studs, runners and furring
channels shall conform to
a) ASTM C 954, “Steel Drill Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to
Steel Studs from 0.033 in. (0.84 mm) to 0.112 in. (2.84 mm) in Thickness,” or
b) ASTM C 1002, “Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal
Plaster Bases to Wood Studs or Steel Studs.”
9.24.1.5. Cladding, Sheathing and Interior Finish Required
1) Cladding or sheathing, and interior finish shall be installed on steel stud framing and shall be fastened
with screws
a) spaced at the appropriate spacing described in Section9.29., and
b) penetrating not less than 10mm through the metal.
9.24.2. Size of Framing
9.24.2.1. Size and Spacing of Studs in Interior Walls
1) Except as required in Articles9.24.2.3. and9.24.2.4., the size and spacing of steel studs for non-loadbearing
interior walls shall conform to Table9.24.2.1.
Table 9.24.2.1.
Steel Studs for Non-Loadbearing Interior Walls
(1)
Forming Part of Sentence 9.24.2.1.(1)
Minimum Stud Size, mm Maximum Stud Spacing, mm Maximum Wall Height, m
32 × 41
400 3.0
600 2.7
32 × 64
300 4.4
400 4.0
600 3.5
32 × 89
300 5.2
400 4.6
600 3.9
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.24.2.2. Thickness of Studs
1) Except as required in Article9.24.2.4., steel studs in non-loadbearing interior walls shall have a metal
thickness of not less than 0.46mm.
9.24.2.3. Runners
1) Runners for interior and exterior non-loadbearing walls shall have a thickness not less than the thickness of
the corresponding studs and shall have not less than 30mm flanges.
9.24.2.4. Openings in Fire Separations
1) Where openings for doors in non-loadbearing fire separations required to have a fire-resistance rating do not
exceed 1 200mm in width,
a) the width of steel studs shall be not less than 63 mm, and
b) the metal thickness shall be not less than 0.46mm.
2) Where openings described in Sentence(1) exceed 1 200mm in width,
a) the width of steel studs shall be not less than 91 mm, and
b) the metal thickness shall be not less than 0.85mm.
3) The distance to the first stud beyond the jamb of any door opening in a fire separation required to have a
fire-resistance rating shall not exceed 400mm.
4) Where the distance between the framing over the opening referred to in Sentence(3) and the top runner
exceeds 400mm in such walls, intermediate support shall be installed at intervals of not more than 400mm above
the opening.
9.24.2.5. Size and Spacing of Studs in Exterior Walls
1) The size and spacing of non-loadbearing steel studs for exterior walls shall conform to Table9.24.2.5.
32 × 152
300 6.6
400 5.8
600 4.9
Notes to Table9.24.2.1.:
(1) The values in the Table are based on a single layer of 12.7 mm gypsum panel sheathing installed on each side of the studs. Where one side is not accessible, gypsum
panels on only one side will suffice. The values are also based on attaching gypsum panel sheathing using screws not smaller than No. 6 spaced at a maximum of
300 mm at edges and at intermediate supports.
Table 9.24.2.5.
Size and Spacing of Steel Studs for Non-Loadbearing Exterior Walls
Forming Part of Sentence 9.24.2.5.(1)
Minimum Stud Size, mm
Minimum Metal Thickness,
mm
Maximum Stud Length, m
Spacing of Studs
300mm o.c. 400mm o.c. 600mm o.c.
30 × 91 0.53 3.0 2.4 –
30 × 91 0.69 3.3 2.7 2.4
30 × 91 0.85 3.6 3.0 2.7
30 × 91 1.0 4.0 3.3 3.0
Table 9.24.2.1. (continued)
Steel Studs for Non-Loadbearing Interior Walls
(1)
Forming Part of Sentence 9.24.2.1.(1)
Minimum Stud Size, mm Maximum Stud Spacing, mm Maximum Wall Height, m
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.24.3. Installation
9.24.3.1. Installation of Runners
1) Runners shall be provided at the tops and bottoms of walls.
2) Runners required in Sentence(1) shall be securely attached to the building at approximately 50mm from the
ends, and at intervals of not more than 600mm o.c. for interior walls and 300mm o.c. for exterior walls.
3) Fasteners used for attachment described in Sentence(2) shall consist of the equivalent of 63mm nails or
25mm screws.
4) Studs at openings and which are not full wall height shall be supported by a runner at the ends of the studs,
securely fastened to the full length studs at the sides of the opening.
9.24.3.2. Fire-Rated Walls
1) Steel studs used in walls required to have a fire-resistance rating shall be installed so that there is not less than a
12mm clearance between the top of the stud and the top of the runner to allow for expansion in the event of fire.
2) Except as provided in Article9.24.3.6., studs in walls referred to in Sentence(1) shall not be attached to the
runners in a manner that will prevent such expansion.
3) Framing above doors with steel door frames in non-loadbearing fire separations required to have a
fire-resistance rating shall consist of 2 runners on the flat fastened back to back. (SeeNoteA-9.24.3.2.(3).)
4) The upper runner required in Sentence(3) shall be bent at each end to extend upwards not less than 150mm
and fastened to the adjacent studs.
5) A gypsum board filler piece, the width and length of the runner, shall be provided between the door frame
referred to in Sentence(3) and the adjacent runner.
9.24.3.3. Orientation of Studs
1) Steel studs shall be installed with webs at right angles to the wall face and, except at openings, shall be
continuous for the full wall height.
9.24.3.4. Support for Cladding Materials
1) Corners and intersections of walls shall be constructed to provide support for the cladding materials.
9.24.3.5. Framing around Openings
1) Studs shall be doubled on each side of every opening where such openings involve more than one stud space,
and shall be tripled where the openings in exterior walls exceed 2.4m in width.
2) Studs described in Sentence(1) shall be fastened together by screws, crimping or welding to act as a single
structural unit in resisting transverse loads.
9.24.3.6. Attachment of Studs to Runners
1) Studs shall be attached to runners by screws, crimping or welding around wall openings and elsewhere where
necessary to keep the studs in alignment during construction.
2) Where clearance for expansion is required in Article9.24.3.2., attachment required in Sentence(1) shall be
applied between studs and bottom runners only.
9.24.3.7. Openings for Fire Dampers
1) Openings for fire dampers in non-loadbearing fire separations required to have a fire-resistance rating shall be
framed with double studs on each side of the opening.
2) The sill and header for openings described in Sentence(1) shall consist of a runner track with right angle
bends made on each end so as to extend 300mm above the header or below the sill and fastened to the studs.
3)
The openings described in Sentence(1) shall be lined with a layer of gypsum board not less than 12.7mm
thick fastened to stud and runner webs.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.25. Heat Transfer, Air Leakage and
Condensation Control
9.25.1. General
9.25.1.1. Scope and Application
1) This Section is concerned with heat, air and water vapour transfer and measures to control condensation.
2) All walls, ceilings and floors separating conditioned space from unconditioned space, the exterior air or the
ground shall be
a) provided with
i) thermal insulation conforming to Subsection9.25.2. and Section9.36.,
ii) an air barrier conforming to Subsection9.25.3. and Section9.36., and
iii) a vapour barrier conforming to Subsection9.25.4., and
b) constructed in such a way that the properties and relative position of all materials conform to
Subsection9.25.5.
3) Insulation and sealing of heating and ventilating ducts shall conform to Sections9.32.,9.33. and9.36.
9.25.2. Thermal Insulation
9.25.2.1. Required Insulation
1) All walls, ceilings and floors separating heated space from unheated space, the exterior air or the exterior soil
shall be provided with sufficient thermal insulation to prevent moisture condensation on their room side during the
winter and to ensure comfortable conditions for the occupants. (SeeNoteA-9.1.1.1.(1).)
9.25.2.2. Insulation Materials
1) Except as required in Sentence(2), thermal insulation shall conform to the requirements of
a) ASTM C 726, “Mineral Wool Roof Insulation Board,”
b) CAN/CGSB-51.25-M, “Thermal Insulation, Phenolic, Faced,”
c) CGSB 51-GP-27M, “Thermal Insulation, Polystyrene, Loose Fill,”
d) CAN/ULC-S701, “Thermal Insulation, Polystyrene, Boards and Pipe Covering,”
e) CAN/ULC-S702, “Mineral Fibre Thermal Insulation for Buildings,”
f) CAN/ULC-S703, “Cellulose Fibre Insulation for Buildings,”
g) CAN/ULC-S704, “Thermal Insulation, Polyurethane and Polyisocyanurate, Boards, Faced,”
h) CAN/ULC-S705.1, “Thermal Insulation – Spray Applied Rigid Polyurethane Foam, Medium Density –
Material – Specification,” or
i) CAN/ULC-S706, “Wood Fibre Insulating Boards for Buildings.”
2) The flame-spread ratings requirements contained in the standards listed in Sentence(1) shall not apply.
(SeeNoteA-9.25.2.2.(2).)
3) Insulation in contact with the ground shall be inert to the action of soil and water and shall be such that its
insulative properties are not significantly reduced by moisture.
9.25.2.3. Installation of Thermal Insulation
1) Insulation shall be installed so that there is a reasonably uniform insulating value over the entire face of the
insulated area.
2) Insulation shall be applied to the full width and length of the space between furring or framing.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
3) Except where the insulation provides the principal resistance to air leakage, thermal insulation shall be
installed so that at least one face is in full and continuous contact with an element with low air permeance.
(SeeNoteA-9.25.2.3.(3).)
4) Insulation on the interior of foundation walls enclosing a crawl space shall be applied so that there is not less
than 50mm clearance above the crawl space floor, if the insulation is of a type that may be damaged by water.
5) Insulation around concrete slabs-on-ground shall be located so that heat from the building is not restricted
from reaching the ground beneath the perimeter, where exterior walls are not supported by footings extending below
frost level.
6) Where insulation is exposed to the weather and subject to mechanical damage, it shall be protected with not
less than
a) reserved
,
b) 6mm preservative-treated plywood, or
c) 12mm cement parging on wire lath applied to the exposed face and edge.
7) Insulation located in areas where it may be subject to mechanical damage shall be protected by a covering
such as gypsum board, plywood, particleboard, OSB, waferboard or hardboard.
8) Insulation in factory-built buildings shall be installed so that it will not become dislodged during
transportation.
9.25.2.4. Installation of Loose-Fill Insulation
1) Except as provided in Sentences(2) to(6), loose-fill insulation shall be used on horizontal surfaces only.
2) Where loose-fill insulation is installed in an unconfined sloped space, such as an attic space over a sloped
ceiling, the supporting slope shall not be more than
a) 4.5 in 12 for mineral fibre or cellulose fibre insulation, and
b) 2.5 in 12 for other types of insulation.
3) Loose-fill insulation is permitted to be used in wood-frame walls of existing buildings.
(SeeNoteA-9.25.2.4.(3).)
4) Where blown-in insulation is installed in above-ground or below-ground wood-frame walls of new buildings,
a) the density of the installed insulation shall be sufficient to preclude settlement,
b) the insulation shall be installed behind a membrane that will permit visual inspection prior to the installation
of the interior finish,
c) the insulation shall be installed in a manner that will not interfere with the installation of the interior finish,
and
d) no water shall be added to the insulation, unless it can be shown that the added water will not adversely affect
other materials in the assembly.
5) Water repellent loose-fill insulation is permitted to be used between the outer and inner wythes of masonry
cavity walls. (SeeNoteA-9.25.2.4.(5).)
6) Where soffit venting is used, measures shall be taken
a) to prevent loose-fill insulation from blocking the soffit vents and to maintain an open path for circulation of
air from the vents into the attic or roof space, and
b) to minimize airflow into the insulation near the soffit vents to maintain the thermal performance of the
material. (SeeArticle9.19.1.3.)
9.25.2.5. Installation of Spray-Applied Polyurethane
1) Spray-applied polyurethane insulation shall be installed in accordance with CAN/ULC-S705.2, “Thermal
Insulation – Spray Applied Rigid Polyurethane Foam, Medium Density – Application.”
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.25.3. Air Barrier Systems
9.25.3.1. Required Barrier to Air Leakage
1) Wall, ceiling and floor assemblies separating conditioned space from unconditioned space or from the ground
shall be constructed so as to include an air barrier system that will provide a continuous barrier to air leakage
a) from the interior of the building into wall, floor, attic or roof spaces, sufficient to prevent excessive moisture
condensation in such spaces during the winter, and
b) from the exterior or the ground inward sufficient to
i) prevent moisture condensation on the room side during winter,
ii) ensure comfortable conditions for the occupants, and
iii) minimize the ingress of soil gas.
(SeeNoteA-9.25.3.1.(1).)
9.25.3.2. Air Barrier System Properties
(SeeNoteA-9.25.5.1.(1).)
1) Air barrier systems shall possess the characteristics necessary to provide an effective barrier to air infiltration
and exfiltration under differential air pressure due to stack effect, mechanical systems or wind.
2) Where polyethylene sheet is used to provide airtightness in the air barrier system, it shall conform to
CAN/CGSB-51.34-M, “Vapour Barrier, Polyethylene Sheet for Use in Building Construction.”
9.25.3.3. Continuity of the Air Barrier System
1) Where the air barrier system consists of an air-impermeable panel-type material, all joints shall be sealed to
prevent air leakage.
2) Except as provided in Sentence9.25.3.6.(3), where the air barrier system consists of flexible sheet material, all
joints shall be
a) sealed, or
b) lapped not less than 100mm and clamped, such as between framing members, furring or blocking, and rigid
panels.
3) Where an interior wall meets an exterior wall, ceiling, floor or roof required to be provided with air barrier
protection, the air barrier system shall extend across the intersection.
4) Where an interior wall projects through a ceiling or extends to become an exterior wall, spaces in the wall
shall be blocked to provide continuity across those spaces with the air barrier system in the abutting walls or ceiling.
5) Where an interior floor projects through an exterior wall or extends to become an exterior floor, continuity of
the air barrier system shall be maintained from the abutting walls across the floor assembly.
6) Penetrations of the air barrier system, such as those created by the installation of doors, windows, electrical
wiring, electrical boxes, piping or ductwork, shall be sealed to maintain the integrity of the air barrier system over the
entire surface.
7) Where access hatches and sump pit covers are installed through assemblies constructed with an air barrier
system, they shall be weatherstripped around their perimeters to prevent air leakage.
8) Clearances between chimneys or gas vents and the surrounding construction that would permit air leakage
from within the
building into a wall or attic or roof space shall be sealed by noncombustible material to prevent
such leakage.
9.25.3.4. Air Leakage Control in Masonry Walls
(SeeNoteA-9.25.3.4. and 9.25.3.6.)
1) Masonry walls required to provide a barrier to the ingress of air from the ground shall
a) include a course of masonry units without voids, or
b) be sealed with flashing material extending across the full width of the masonry.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) The masonry course or flashing described in Sentence(1) shall
a) be located at the level of the adjoining floor and be sealed to it in accordance with Article9.25.3.6., or
b) in the absence of a floor, be located at the level of the ground cover required by Article9.18.6.1. and be sealed
to it.
9.25.3.5. Air Leakage Control in Underground Roofs
1) Waterproofing systems for roofs of underground structures shall be sealed to the air barrier in the walls.
9.25.3.6. Air Barrier Systems in Floors-on-ground
(SeeNoteA-9.25.3.4. and 9.25.3.6.)
1) Materials used to provide a barrier to the ingress of air through floors-on-ground shall conform to
CAN/CGSB-51.34-M, “Vapour Barrier, Polyethylene Sheet for Use in Building Construction.”
2) Where the floor-on-ground is a concrete slab, the air barrier shall be
a) installed below the slab, or
b) applied to the top of the slab, provided a separate floor is installed over the slab.
(SeeNoteA-9.25.3.6.(2) and (3).)
3) Where the air barrier installed below a floor-on-ground is flexible sheet material, joints in the barrier shall be
lapped not less than 300mm. (SeeNoteA-9.25.3.6.(2) and (3).)
4) Where installed in conjunction with a framed floor-on-ground or above a floor-on-ground, the air barrier
shall be installed in accordance with Article9.25.3.3.
5) A floor-on-ground shall be sealed around its perimeter to the inner surfaces of adjacent walls using
flexible sealant.
6) All penetrations of a floor-on-ground that are required to drain water from the floor surface shall be sealed in
a manner that prevents the upward flow of air without preventing the downward flow of liquid water.
9.25.4. Vapour Barriers
9.25.4.1. Required Barrier to Vapour Diffusion
1) Thermally insulated wall, ceiling and floor assemblies shall be constructed with a vapour barrier so as to
provide a barrier to diffusion of water vapour from the interior into wall spaces, floor spaces or attic or roof spaces.
9.25.4.2. Vapour Barrier Materials
1) Vapour barriers shall have a permeance not greater than 60ng/(Pa·s·m
2
) measured in accordance with
ASTME96/E 96M, “Water Vapor Transmission of Materials,” using the desiccant method (dry cup).
2) Where the intended use of the interior space will result in high moisture generation, the assembly shall be
designed according to Part5. (SeeNoteA-9.25.4.2.(2).)
3) Where polyethylene is installed to serve only as the vapour barrier, it shall comply with Clause4.4, Thermal
Stability, and Clause5.7, Oxidative Induction Time, of CAN/CGSB-51.34-M, “Vapour Barrier, Polyethylene Sheet
for Use in Building Construction.”
4) Membrane-type vapour barriers other than polyethylene shall conform to the requirements of
CAN/CGSB-51.33-M, “Vapour Barrier Sheet, Excluding Polyethylene, for Use in Building Construction.”
5) Where a coating is applied to gypsum board to function as the vapour barrier, the permeance of the coating
shall be determined in accordance with CAN/CGSB-1.501-M, “Method for Permeance of Coated Wallboard.”
6) Where foamed plastic insulation functions as the vapour barrier, it shall be sufficiently thick so as to meet the
requirement of Sentence(1).
9.25.4.3. Installation of Vapour Barriers
1) Products installed to function as the vapour barrier shall protect the warm side of wall, ceiling and floor
assemblies.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
2) Where different products are used for the vapour barrier and the insulation, the vapour barrier shall be
installed sufficiently close to the warm side of the insulation to prevent condensation at design conditions.
(SeeNoteA-9.25.4.3.(2) and NoteA-9.25.5.1.(1).)
3) Where the same product is used for the vapour barrier and the insulation, the product shall be installed
sufficiently close to the warm side of the assembly to prevent condensation at design conditions.
(SeeNotesA-9.25.4.3.(2), A-9.25.5.1.(1) and A-9.25.5.2.)
9.25.5. Properties and Position of Materials in the Building Envelope
9.25.5.1. General
(SeeNoteA-9.25.5.1.)
1) Except as provided in Sentences(2) to(4), sheet and panel-type materials incorporated into assemblies
described in Article9.25.1.1. shall conform to Article9.25.5.2., where
a) the material has
i) an air leakage characteristic less than 0.1L/(s·m
2
) at 75Pa, and
ii) a water vapour permeance less than 60 ng/(Pa·s·m
2
) when measured in accordance with
ASTME96/E96M, “Water Vapor Transmission of Materials,” using the desiccant method (drycup)
(seeNoteA-9.25.5.1.(1)(a)(ii)), and
b) the intended use of the interior space where the materials are installed will not result in high moisture
generation.
(SeeNoteA-9.25.5.1.(1).)
2) Where the intended use of the interior space will result in high moisture generation, the assembly shall be
designed according to Part5.
3) Wood-based sheathing materials not more than 12.5mm thick and complying with Article9.23.17.2. need
not comply with Sentence(1). (SeeNoteA-9.25.5.1.(3).)
4) Where a material has a water vapour permeance not less than 30ng/(Pa∙s∙m
2
) and a thermal resistance not
less than 0.7 (m
2
·K)/W and the heating degree-days of the building location are less than 6 000, the assembly need
not comply with Sentence(1).
9.25.5.2. Position of Low Permeance Materials
(SeeNoteA-9.25.5.2.)
1) Sheet and panel-type materials described in Article9.25.5.1. shall be installed
a) on the warm face of the assembly (seealso Article9.25.4.2.),
b) at a location where the ratio between the total thermal resistance of all materials outboard of its innermost
impermeable surface and the total thermal resistance of all materials inboard of that surface is not less than
that required by Table9.25.5.2., or
c) outboard of an air space that is vented to the outdoors.
2) For walls, the air space described in Clause(1)(c) shall comply with Clause9.27.2.2.(1)(a).
Table 9.25.5.2.
Ratio of Outboard to Inboard Thermal Resistance
Forming Part of Sentence 9.25.5.2.(1)
Heating Degree-Days of Building Location
(1)
, Celsius degree-days
Minimum Ratio of Total Thermal Resistance Outboard of Material’s Inner Surface
to Total Thermal Resistance Inboard of Material’s Inner Surface
up to 4 999 0.20
5 000 to 5 999 0.30
6 000 to 6 999 0.35
7 000 to 7 999 0.40
8 000 to 8 999 0.50
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9 000 to 9 999 0.55
10 000 to 10 999 0.60
11 000 to 11 999 0.65
12 000 or higher 0.75
Notes to Table9.25.5.2.:
(1) See Sentence 1.1.3.1.(1).
Table 9.25.5.2. (continued)
Ratio of Outboard to Inboard Thermal Resistance
Forming Part of Sentence 9.25.5.2.(1)
Heating Degree-Days of Building Location
(1)
, Celsius degree-days
Minimum Ratio of Total Thermal Resistance Outboard of Material’s Inner Surface
to Total Thermal Resistance Inboard of Material’s Inner Surface
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.26. Roofing
9.26.1. General
9.26.1.1. Definitions
1) For the purpose of this Section, the term “roof” shall mean sloped or near-horizontal assemblies that protect
the spaces beneath them, including platforms that effectively serve as roofs with respect to the accumulation or
drainage of precipitation. (SeeNoteA-9.26.1.1.(1).)
2) For the purpose of this Section, the term “roofing” shall mean the primary covering for roofs.
9.26.1.2. Required Protection
1) Roofs shall be protected with roofing, including flashing, installed so as to
a) effectively shed water,
b) prevent the ingress of water and moisture into building assemblies and occupied space, and
c) minimize the ingress of water due to ice damming into building assemblies.
2) Compliance with Sentence(1) shall be demonstrated by conforming to
a) the remainder of this Subsection, or
b) Part5.
9.26.1.3. Alternative Installation Methods
1) Methods described in CAN3-A123.51-M, “Asphalt Shingle Application on Roof Slopes 1:3 and Steeper,” or
in CAN3-A123.52-M, “Asphalt Shingle Application on Roof Slopes 1:6 to LessThan1:3,” are permitted to be used
for asphalt shingle applications not described in this Section.
9.26.2. Roofing Materials
9.26.2.1. Material Standards
1) M
aterials used for the preparation of the substrate for roofing shall conform to the requirements of the
applicable standards in Table 9.26.2.1.-A.
2) R
oofing materials shall conform to the requirements of the applicable standards in Table 9.26.2.1.-B.
Table 9.26.2.1.-A
Materials for Preparation of the Substrate for Roofing
Forming Part of Sentence 9.26.2.1.(1)
Typeof Material Standards
Sheathing membranes CAN/CGSB-51.32-M, “Sheathing, Membrane, Breather Type”
Primers CGSB 37-GP-9Ma, “Primer, Asphalt, Unfilled, for Asphalt Roofing, Dampproofing and Waterproofing”
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
3) Cedar shingles and shakes shall be certified as to grade by an agency accredited by the Standards Council of
Canada.
9.26.2.2. Installation of Materials
1) Materials listed in Tables9.26.2.1.-A and9.26.2.1.-B shall be installed in conformance with the
manufacturer’s written instructions. (SeeSentence1.5.1.2.(1)of DivisionA.)
9.26.2.3. Nails
1) Nails used for roofing shall be corrosion-resistant roofing or shingle nails conforming to
a) ASTMF1667, “Driven Fasteners: Nails, Spikes, and Staples,” or
b) CSAB111, “Wire Nails, Spikes and Staples.”
2) Nails shall have sufficient length to penetrate through, or 12mm into, roof sheathing.
3) Nails used with asphalt roofing shall have a head diameter of not less than 9.5mm and a shank thickness of
notless than 2.95mm.
4) Nails used with wood shingles or shakes shall have a head diameter of not less than 4.8mm and a shank
thickness of not less than 2.0mm and shall be stainless steel, aluminum or hot-dipped galvanized.
(SeeNoteA-9.26.2.3.(4).)
Table 9.26.2.1.-B
Roofing Materials
Forming Part of Sentence 9.26.2.1.(2)
Types of Roof Covering Standards
Built-up roofing (BUR) ASTM D 3019, “Lap Cement Used with Asphalt Roll Roofing, Non-Fibered, Asbestos-Fibered, and Non-Asbestos-Fibered”
(1)
ASTM D 4479/D 4479M, “Asphalt Roof Coatings – Asbestos-Free”
CGSB 37-GP-56M, “Membrane, Modified, Bituminous, Prefabricated, and Reinforced for Roofing”
CAN/CGSB-37.50-M, “Hot-Applied, Rubberized Asphalt for Roofing and Waterproofing”
CAN/CSA-A123.2, “Asphalt-Coated Roofing Sheets”
CSA A123.3, “Asphalt Saturated Organic Roofing Felt”
CAN/CSA-A123.4, “Asphalt for Constructing Built-Up Roof Coverings and Waterproofing Systems”
CSA A123.17, “Asphalt Glass Felt Used in Roofing and Waterproofing”
Single-ply membranes CAN/CGSB-37.54, “Polyvinyl Chloride Roofing and Waterproofing Membrane”
CAN/CGSB-37.58-M, “Membrane, Elastomeric, Cold-Applied Liquid, for Non-Exposed Use in Roofing and Waterproofing”
ASTM D 4637/D 4637M, “EPDM Sheet Used In Single-Ply Roof Membrane”
ASTM D 4811/D 4811M, “Nonvulcanized (Uncured) Rubber Sheet Used as Roof Flashing”
ASTM D 6878/D 6878M, “Thermoplastic Polyolefin Based Sheet Roofing”
Shingles, shakes, tiles,
panels
CSA A123.1/A123.5, “Asphalt Shingles Made From Organic Felt and Surfaced with Mineral Granules/Asphalt Shingles Made
From Glass Felt and Surfaced with Mineral Granules”
CAN/CSA-A220, “Concrete Roof Tiles”
CSA O118.1, “Western Red Cedar Shakes and Shingles”
CSA O118.2, “Eastern White Cedar Shingles”
Eave protection CSA A123.22, “Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam
Protection”
Flashing ASTM D 4811/D 4811M, “Nonvulcanized (Uncured) Rubber Sheet Used as Roof Flashing”
Notes to Table9.26.2.1.-B:
(1) For the purpose of this Subsection, ASTM D 3019 shall only apply to the non-fibered and non-asbestos-fibered types of asphalt roll roofing.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.26.2.4. Staples
1) Staples used to apply asphalt or wood shingles shall be corrosion-resistant and shall be driven with the crown
parallel to the eaves.
2) Staples used with asphalt shingles shall be not less than 19mm long, 1.6mm diam or thickness, with not less
than a 25mm crown, except that an 11mm crown may be used as provided in Sentence9.26.7.4.(2).
3) Staples used with wood shingles shall be not less than 29mm long, 1.6mm diam or thickness, with not less
than a 9.5mm crown and shall be stainless steel or aluminum. (SeeNoteA-9.26.2.3.(4).)
9.26.3. Slope of Roofed Surfaces
9.26.3.1. Slope
1) Except as provided in Sentences(2) and(3), the slopes on which roof coverings may be applied shall conform
to Table9.26.3.1.
2) Asphalt and gravel or coal tar and gravel roofs may be constructed with lower slopes than required in
Sentence(1) when effective drainage is provided by roof drains located at the lowest points on the roofs.
3) Profiled metal roof cladding systems specifically designed for low-slope applications are permitted to be
installed with lower slopes than required by Sentence(1), provided they are installed in conformance with the
manufacturer’s written recommendations.
4) Except where back-slope will not adversely affect adjacent supported or supporting constructions due to water
ingress, roofs and constructions that effectively serve as roofs shall be constructed with sufficient slope away from
a) exterior walls, and
b) guards that are connected to the roof, or to a construction that effectively serves as a roof, by more than
pickets or posts.
(SeeNotesA-9.26.1.1.(1), A-9.26.4.1. and A-9.27.3.8.(4).)
5) The slope required by Sentence(4) shall be sufficient to maintain a positive slope
a) after expected shrinkage of the building frame, where these surfaces are supported by exterior walls and
exterior columns (seeNoteA-9.27.3.8.(4)), and
b) once design loading is taken into consideration, where these surfaces are cantilevered from exterior walls.
Table 9.26.3.1.
Roofing Types and Slope Limits
Forming Part of Sentence 9.26.3.1.(1)
Typeof Roofing Minimum Slope Maximum Slope
Asphalt Shingles
Low slope application 1 in 6 no limit
Normal application 1 in 3 no limit
Built-up Roofing
Asphalt base (without gravel) 1 in 25 1 in 2
Asphalt base (gravelled) 1 in 50
(1)
1 in 4
Coal-tar base (gravelled) 1 in 50
(1)
1 in 25
Cold process 1 in 25 1 in 1.33
Cedar Shakes 1 in 3 no limit
Clay Tile 1 in 2 no limit
Glass Fibre Reinforced Polyester Roofing Panels 1 in 4 no limit
Modified Bituminous Membranes 1 in 50 1 in 4
Profiled Metal Roofing 1 in 4
(1)
no limit
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.26.4. Flashing at Intersections
9.26.4.1. Required Flashing at Intersections
(SeeNotesA-9.26.4.1. and A-9.26.1.1.(1).)
1) Except where the omission of flashing will not adversely affect adjacent supported or supporting
constructions, flashing shall be installed at junctions between roofs and
a) walls that rise above the roof, and
b) guards that are connected to the roof by more than pickets or posts.
2) For the purpose of Sentence(1), roofs shall include platforms that effectively serve as roofs with respect to the
accumulation or drainage of precipitation.
9.26.4.2. Materials
1) Sheet metal flashing shall consist of not less than
a) 1.73mm thick sheet lead,
b) 0.33mm thick galvanized steel,
c) 0.33mm thick copper,
d) 0.35mm thick zinc, or
e) 0.48mm thick aluminum.
9.26.4.3. Valley Flashing
1) Where sloping surfaces of shingled roofs intersect to form a valley, the valley shall be flashed.
2) Valley flashing shall be installed over continuous sheathing.
3) Closed valleys shall not be used with rigid shingles on slopes of less than 1in1.2.
4) Open valleys shall be flashed with at least
a) one layer of sheet metal not less than 600mm wide, or
b) 2 layers of roll roofing.
5) The bottom layer of roofing required in Sentence(4) shall consist of at least TypeS smooth roll roofing or
TypeM mineral surface roll roofing (mineral surface down) not less than 457mm wide, centred in the valley and
fastened with nails spaced not more than 450mm o.c. located 25mm away from the edges.
Roll Roofing
480 mm wide selvage asphalt roofing 1 in 6 no limit
Cold application felt 1 in 50 1 in 1.33
Smooth and mineral surfaced 1 in 4 no limit
Sheet Metal Shingles 1 in 4
(1)
no limit
Slate Shingles 1 in 2 no limit
Wood Shingles 1 in 4 no limit
Notes to Table9.26.3.1.:
(1) See Sentence 9.26.3.1.(3).
Table 9.26.3.1. (continued)
Roofing Types and Slope Limits
Forming Part of Sentence 9.26.3.1.(1) (continued)
Typeof Roofing Minimum Slope Maximum Slope
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
6) The top layer of roofing required in Sentence(4) shall consist of at least TypeM mineral surface roll roofing
(mineral surface up), 914mm wide, centred in the valley, applied over a 100mm wide strip of cement along each
edge of the bottom layer, and fastened with a sufficient number of nails to hold it in place until the shingles are
applied.
9.26.4.4. Intersection of Shingle Roofs and Masonry
1) The intersection of shingle roofs and masonry walls or chimneys shall be protected with flashing.
2) Counter flashing required in Sentence(1) shall be embedded not less than 25mm in the masonry and shall
extend not less than 150mm down the masonry and lap the lower flashing not less than 100mm.
3) Flashing along the slopes of a roof described in Sentence(1) shall be stepped so that there is not less than a
75mm head lap in both the lower flashing and counter flashing.
4) Where the roof described in Sentence(1) slopes upwards from the masonry, the flashing shall extend up the
roof slope to a point equal in height to the flashing on the masonry, but not less than 1.5times the shingle exposure.
9.26.4.5. Intersection of Shingle Roofs and Walls other than Masonry
1) The intersection of shingle roofs and walls clad with other than masonry shall be protected with flashing.
2) Flashing required in Sentence(1) shall be installed so that it extends up the wall not less than 75mm behind
the sheathing paper, and extends not less than 75mm horizontally.
3) Along the slope of the roof, the flashing required in Sentence(1) shall be stepped with not less than a 75mm
head lap.
9.26.4.6. Intersection of Built-Up Roofs and Masonry
1) The intersection of built-up roofs with masonry walls or chimneys shall have a cant strip at the intersection,
and a roofing membrane shall be mopped over the cant strip and not less than 150mm up the wall.
2) Counter flashing installed over the intersection referred to in Sentence(1) shall be embedded not less than
25mm in the masonry, and shall be of sufficient length to extend down not less than 150mm, lapping the
membrane on the masonry not less than 100mm.
9.26.4.7. Intersection of Built-Up Roofs and Walls other than Masonry
1) The intersection of built-up roofs with walls clad with other than masonry shall have a cant strip at the
intersection.
2) The roofing membrane shall be mopped over the cant strip referred to in Sentence(1).
3) Flashing plies shall extend not less than 150mm up the wall referred to in Sentence(1) behind the
sheathing paper.
9.26.4.8. Chimney Saddles
1) Except as otherwise permitted in Sentence(5), chimney saddles shall be installed where the upper side of a
chimney on a sloping roof is more than 750mm wide.
2) Chimney saddles shall be covered with sheet metal or roofing material of weight and quality equivalent to
the roofing.
3) Saddles shall be flashed where they intersect the roof.
4) The intersection of the saddle and the chimney shall be flashed and counterflashed as described in
Article9.26.4.4.
5) A chimney saddle need not be installed if the intersection between the chimney and roof is protected by sheet
metal flashing that extends up the
chimney to a height equal to at least one sixth the width of the chimney, but not less
than 150mm, and up the roof slope to a point equal in height to the flashing on the chimney, but not less than
1.5times the shingle exposure.
6) Flashing described in Sentence(5) at the chimney shall be counterflashed as required by Article9.26.4.4.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.26.5. Eave Protection for Shingles and Shakes
9.26.5.1. Required Eave Protection
1) Except as provided in Sentence(2), eave protection shall be provided on shingle, shake or tile roofs, extending
from the edge of the roof a minimum of 900mm up the roof slope to a line not less than 300mm inside the inner
face of the exterior wall.
2) Eave protection is not required
a) over unheated garages, carports and porches,
b) where the roof overhang exceeds 900mm measured along the roof slope from the edge of the roof to the
inner face of the exterior wall,
c) on roofs of asphalt shingles installed in accordance with Subsection9.26.8.,
d) on roofs with slopes of 1in1.5 or greater, or
e) in regions with 3 500 or fewer degree-days.
9.26.5.2. Materials
1) Eave protection shall be laid beneath the starter strip and shall consist of
a) No.15 asphalt-saturated felt laid in two plies lapped 480mm and cemented together with lap cement,
b) TypeM or S roll roofing laid with not less than 100mm head and end laps cemented together with
lap cement,
c) glass fibre or polyester fibre coated base sheets, or
d) self-sealing composite membranes consisting of modified bituminous coated material.
9.26.6. Underlay beneath Shingles
9.26.6.1. Materials
1) Except as required in Sentence(2), when underlay is used beneath shingles, it shall be
a) asphalt-saturated sheathing paper weighing not less than 0.195kg/m
2
, or
b) No.15 plain or perforated asphalt-saturated felt.
2) Underlay used beneath wood shingles shall be breather type.
9.26.6.2. Installation
1) When used with shingles, underlay shall be installed parallel to the eaves with head and end lap of not less
than 50mm.
2) The top edge of each strip of underlay referred to in Sentence(1) shall be fastened with sufficient roofing
nails to hold it in place until the shingles are applied.
3) The underlay referred to in Sentence(1) shall overlap the eave protection by not less than 100mm.
(SeeArticle9.26.10.2. for underlay beneath wood shakes.)
9.26.7. Asphalt Shingles on Slopes of 1 in 3 or Greater
9.26.7.1. Coverage
1) Coverage shall be not less than 2 thicknesses of shingle over the entire roof, disregarding cutouts.
9.26.7.2. Starter Strip
1) A starter strip shall be installed along the lower edge of the roof so that it extends approximately 12mm
beyond the eaves and rake of the roof and fastened along the bottom edge with nails spaced not more than
300mm o.c.
2) Starter strips shall be
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
a) at least TypeM mineral-surfaced roll roofing not less than 300mm wide,
b) shingles of the same weight and quality as those used as a roof covering with tabs facing up the roof slope, or
c) pre-manufactured starter strips installed with sealant at the eaves.
3) Starter strips need not be provided where eave protection of not less than TypeM mineral-surfaced roll
roofing is provided.
9.26.7.3. Head Lap
1) Shingles shall have a head lap of not less than 50mm.
9.26.7.4. Fasteners
1) Except as provided in Sentence(2), shingles shall be fastened with at least 4 nails or staples for 1m wide
shingles so that no nails or staples are exposed.
2) Where staples with an 11mm crown are used, shingles shall be fastened with at least 6 staples.
3) Fasteners may be reduced for narrower shingles in proportion to the width of the shingle or when shingles
incorporating interlocking devices are used.
4) Fasteners referred to in Sentences(1) and(2) shall be located 25mm to 40mm from each end of each strip
shingle with other fasteners equally spaced between them.
5) Fasteners referred to in Sentences(1) and(2) shall be located not less than 12mm above the tops of
the cutouts.
9.26.7.5. Securing of Tabs
1) Shingle tabs shall be secured by a spot of plastic cement not exceeding 25mm diam under the centre of each
tab or by interlocking devices or self-sealing strips.
9.26.7.6. Hips and Ridges
1) Shingles on hips and ridges shall be applied so they extend not less than 100mm on either side of the hip or
ridge, and shall be lapped not less than 150mm.
2) Shingles referred to in Sentence(1) shall be fastened with nails or staples on each side located not more than
25mm from the edge and 25mm above the butt of the overlying shingle.
9.26.7.7. Eave Protection
1) Eave protection shall conform to Subsection9.26.5.
9.26.7.8. Flashing
1) Flashing shall conform to Subsection9.26.4.
9.26.8. Asphalt Shingles on Slopes of less than 1 in 3
9.26.8.1. Coverage
1) Except for the first 2 courses, coverage shall be not less than 3 thicknesses of shingle over the entire roof,
disregarding cutouts.
9.26.8.2. Starter Strip
1) A starter strip shall be installed as in Article9.26.7.2.
2) Starter strips required in Sentence(1) shall be laid in a continuous band of cement not less than
200mm wide.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.26.8.3. Securing of Tabs
1) Shingle tabs shall be secured with cold application cement applied at the rate of not less than 0.5L/m
2
of
cemented area, or hot application asphalt applied at the rate of 1kg/m
2
of cemented area.
9.26.8.4. Securing of Shingle Courses
1) The first course of shingles shall be secured by a continuous band of cement along the eaves applied so that
the width of the band equals the shingle exposure plus 100mm.
2) The succeeding courses of shingles shall be secured by a continuous band of cement applied so that the width
of the band equals the shingle exposure plus 50mm.
3) The band required in Sentence(2) shall be located not more than 50mm above the butt of the overlying
course of shingles.
9.26.8.5. Hips and Ridges
1) Shingles on hips and ridges shall be not less than 300mm wide applied to provide triple coverage.
2) Shingles referred to in Sentence(1) shall be cemented to the roof shingles and to each other with a coat of
cement and fastened with nails or staples located 40mm above the butt of the overlying shingle and 50mm from
eachedge.
9.26.8.6. Flashing
1) Flashing shall conform to Subsection9.26.4.
9.26.8.7. Fastening
1) Shingles shall be fastened in accordance with Article9.26.7.4.
9.26.9. Wood Roof Shingles
9.26.9.1. Decking
1) Except as provided in Sentence9.23.16.1.(1), decking for wood shingled roofs may be continuous or spaced.
9.26.9.2. Grade
1) Western cedar shingles shall be not less than No. 2 grade.
2) Eastern white cedar shingles shall be not less than B(clear) grade.
9.26.9.3. Size
1) Wood shingles shall be not less than 400mm long and not less than 75mm or more than 350mm wide.
9.26.9.4. Spacing and Joints
1) Shingles shall be spaced approximately 6mm apart and offset at the joints in adjacent courses not less than
40mm so that joints in alternate courses are staggered.
9.26.9.5. Fastening
1) Shingles shall be fastened with 2nails or staples located approximately 20mm from the sides of the shingle
and 40mm above the exposure line.
9.26.9.6. Exposure
1) The exposure of wood roof shingles shall conform to Table9.26.9.6.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.26.9.7. Flashing
1) Flashing shall conform to Subsection9.26.4.
9.26.9.8. Eave Protection
1) Eave protection shall conform to Subsection9.26.5.
9.26.10. Cedar Roof Shakes
9.26.10.1. Size and Thickness
1) Shakes shall be not less than 450mm long and not less than 100mm nor more than 350mm wide with a
butt thickness of not more than 32mm and not less than 9mm.
9.26.10.2. Underlay
1) Where eave protection is not provided, an underlay conforming to the requirements in Article9.26.6.1. for
wood shingles shall be laid as a strip not less than 900mm wide along the eaves.
2) A strip of material similar to that described in Sentence(1) not less than 450mm wide shall be interlaid
between each course of shakes with the bottom edge of the strip positioned above the butt line at a distance equal to
double the exposure of the shakes.
3) Interlaid strips referred to in Sentence(2) shall be lapped not less than 150mm at hips and ridges in a
manner that will prevent water from reaching the roof sheathing.
9.26.10.3. Spacing and Joints
1) Shakes shall be spaced 6mm to 9mm apart and the joints in any one course shall be separated not less than
40mm from joints in adjacent courses.
9.26.10.4. Fastening
1) Shakes shall be fastened with nails located approximately 20mm from the sides of the shakes and 40mm
above the exposure line.
9.26.10.5. Exposure
1) The exposure of wood shakes shall not exceed
a) 190mm for shakes not less than 450mm long, and
b) 250mm for shakes not less than 600mm long.
9.26.10.6. Flashing
1) Flashing shall conform to Subsection9.26.4.
9.26.10.7. Eave Protection
1) Eave protection shall conform to Subsection9.26.5.
Table 9.26.9.6.
Exposure of Wood Roof Shingles
Forming Part of Sentence 9.26.9.6.(1)
Roof Slope
Maximum Exposure, mm
No.1 or A Grade Length of Shingle, mm No.2 or B Grade Length of Shingle, mm
400 450 600 400 450 600
< 1 in 3 100 115 165 90 100 140
≥ 1 in 3 125 140 190 100 115 165
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.26.10.8. Grade
1) Shakes shall be not less than No.1 or Handsplit grade.
9.26.11. Built-Up Roofs
9.26.11.1. Quantity of Materials
1) The quantities of bituminous materials used on built-up roofs shall conform to Table9.26.11.1.
9.26.11.2. Coal-Tar and Asphalt Products
1) Coal-tar products and asphalt products shall not be used together in built-up roof construction.
9.26.11.3. Roof Felts
1) Bitumen roofing felts shall be at least No.15 felt.
9.26.11.4. Aggregate Surfacing
1) Aggregate used for surfacing built-up roofs shall be clean, dry and durable and shall consist of particles of
gravel, crushed stone or air-cooled blast furnace slag having a size of from 6mm to 15mm.
2) The minimum amount of aggregate surfacing per square metre of roof surface shall be 15kg gravel or crushed
stone or 10kg crushed slag.
9.26.11.5. Flashing
1) Flashing for built-up roofs shall conform to Subsection9.26.4.
9.26.11.6. Number of Layers
1) Built-up roofing shall consist of not less than 3mopped-down layers of roofing felt flood coated
with bitumen.
9.26.11.7. Installation of Layers
1) In hot process applications each layer of bitumen-saturated felt shall be laid while the bitumen is hot, with
each layer overlapping the previous one.
2) The full width under each lap referred to in Sentence(1) shall be coated with bitumen so that in no place
does felt touch felt.
3) Felt shall be laid free of wrinkles and shall be rolled directly into the hot bitumen and broomed forward and
outward from the centre to ensure complete adhesion.
9.26.11.8. Roofing over Wood-Based Sheathing
1) Except as permitted in Sentence(2), built-up roofing applied over wood, plywood, OSB or waferboard roof
sheathing shall be laid over an additional base layer of felt laid dry over the entire roof deck with not less than a
50mm headlap and a 50mm sidelap between each sheet.
Table 9.26.11.1.
Quantities of Bitumen for Built-up Roofs
Forming Part of Sentence 9.26.11.1.(1)
Type of Roof
Amount of Bitumen per Square Metre of Roof Surface
Mopping Coats between Layers Flood Coat
Asphalt and aggregate 1 kg 3 kg
Coal-tar and aggregate 1.2 kg 3.6 kg
Cold process roofing 0.75 L cold process cement 2 L cold process top coating
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
2) Where plywood, OSB or waferboard roof sheathing is used, the dry layer of felt required in Sentence(1) may
be omitted when the joints are taped and the sheathing is primed with asphalt.
9.26.11.9. Attachment to Decking
1) Roofing shall be securely attached to the decking or where insulation is applied above the deck, the insulation
shall be securely attached to the deck before the first layer of felt is fastened to the insulation.
9.26.11.10. Cant Strips
1) Except as permitted in Sentence(4), a cant strip shall be provided at the edges of roofs.
2) At least 2 plies of the roofing membrane shall be carried over the top of the cant strip.
3) Flashing shall extend over the top of the cant strip and be shaped to form a drip.
4) The cant strip required in Sentence(1) need not be provided where a gravel stop is installed at the edge
of roofs.
5) The roofing membranes shall be carried over the edge of the roof before the gravel stop referred to in
Sentence(4) is fastened and 2 plies of roofing membrane mopped to the top surface of the gravel stop before the
flood coat is applied.
6) The gravel stop referred to in Sentence(4) shall extend over the edge of the roof to form a drip or shall be
flashed so that the flashing extends over the edge to form a drip.
9.26.12. Selvage Roofing
9.26.12.1. Coverage
1) Wide selvage asphalt roofing shall provide double coverage over the entire roof surface.
9.26.12.2. Joints
1) Plies of selvage roofing shall be cemented together to ensure a watertight joint.
9.26.13. Sheet Metal Roofing
9.26.13.1. Thickness
1) Sheet metal roofing shall be not less than
a) 0.33mm thick galvanized steel,
b) 0.46mm thick copper,
c) 0.46mm thick zinc, or
d) 0.48mm thick aluminum.
9.26.13.2. Support
1) Except as provided in Sentence9.23.16.1.(1), where sheet metal roofing is not supported by roof decking but
spans between spaced supports, the panels shall be designed to support the specified live loads for roofs.
9.26.14. Glass Reinforced Polyester Roofing
9.26.14.1. Support
1) Except as provided in Sentence9.23.16.1.(1), where glass-reinforced polyester roofing panels are not
supported by roof decking but span between spaced supports, the panels shall be designed to support the specified
live roof loads.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.26.15. Hot Applied Rubberized Asphalt Roofing
9.26.15.1. Installation
1) Hot applied rubberized asphalt roofing shall be installed in accordance with CAN/CGSB-37.51-M,
“Application for Hot-Applied Rubberized Asphalt for Roofing and Waterproofing.”
9.26.16. Polyvinyl Chloride Sheet Roofing
9.26.16.1. Installation
1) Polyvinyl chloride sheet applied roofing membrane shall be installed in accordance with CGSB37-GP-55M,
“Application of Sheet Applied Flexible Polyvinyl Chloride Roofing Membrane.”
9.26.17. Concrete Roof Tiles
9.26.17.1. Installation
1) Except as provided in Sentence9.23.16.1.(1), concrete roof tiles shall be installed according to
CAN/CSA-A220, “Concrete Roof Tiles.” (SeeNoteA-9.26.17.1.(1).)
9.26.18. Roof Drains and Downspouts
9.26.18.1. Roof Drains
1) When roof drains are provided they shall conform to Part7.
9.26.18.2. Downspouts
1) Where downspouts are provided and are not connected to a sewer, extensions shall be provided to carry
rainwater away from the building in a manner which will prevent soil erosion.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.27. Cladding
9.27.1. Application
9.27.1.1. General
1) Where lumber, wood shingles, shakes, fibre-cement shingles, planks and sheets, plywood, OSB, waferboard,
hardboard, vinyl, aluminum or steel, including trim and soffits, are installed as cladding on wood-frame walls
exposed to precipitation, the cladding assembly shall comply with
a) Subsections9.27.2. to9.27.12., or
b) Part5.
2) Where stucco is installed as cladding on wood-frame or masonry walls exposed to precipitation, the cladding
assembly shall comply with
a) Subsections9.27.2. to9.27.5., and Section9.28., or
b) Part5.
3) Where masonry serves as cladding on wood-frame or masonry walls exposed to precipitation, the cladding
assembly shall comply with
a) Subsections9.27.2. to9.27.4., and Section9.20., or
b) Part5.
4) Where asphalt shingles are installed as cladding on wood-frame walls exposed to precipitation, the cladding
assembly shall comply with
a) Subsections9.26.7. and9.27.2. to9.27.4., or
b) Part5.
5) Where an exterior insulation finish system is installed as cladding on wood-frame, masonry, cold-formed steel
stud or cast-in-place concrete walls exposed to precipitation, the cladding assembly shall comply with
a) Subsections9.25.5.,9.27.2. to9.27.4., and9.27.13., or
b) Part5.
(SeeNoteA-9.27.1.1.(5).)
6) Where cladding materials other than those described in Sentences(1) to(5) are installed, or where the
cladding materials described in Sentences(1) to(5) are installed on substrates other than those identified in
Sentences(1) to(5), the materials and installation shall comply with Part5.
9.27.2. Required Protection from Precipitation
(SeeNoteA-9.27.2.)
9.27.2.1. Minimizing and Preventing Ingress and Damage
1) Except where exterior walls are protected from precipitation or where it can be shown that precipitation
ingress will not adversely affect occupant health or safety, exterior walls shall be designed and constructed to
a) minimize the ingress of precipitation into the assembly, and
b) prevent the ingress of precipitation into interior space.
(SeeNoteA-9.27.2.1.(1).)
2) Except where exterior walls are protected from specific mechanisms of deterioration, such as mechanical
impact and ultraviolet radiation, exterior walls shall be designed and constructed to minimize the likelihood of their
required performance being reduced to an unacceptable level as a result of those mechanisms.
9.27.2.2. Minimum Protection from Precipitation Ingress
(SeeNoteA-9.27.2.2.)
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
1) Except as provided in Sentence(2), a cladding assembly is deemed to have a capillary break between the
cladding and the backing assembly, where
a) there is a drained and vented air space not less than 9.5mm deep behind the cladding, over the full height
and width of the wall (seealso Article9.27.5.3.),
b) an open drainage material, not less than 9.5mm thick and with a cross-sectional area that is not less than
80% open, is installed between the cladding and the backing, over the full height and width of the wall,
c) the cladding’s components are hollow-backed metal or vinyl and are horizontally oriented and loosely
fastened to the backing substrate,
d) the wall is a masonry cavity wall or the cladding is masonry veneer constructed according to Section9.20., or
e) the cladding conforms to Subsection9.27.13.
2) The drained and vented air space, and drainage material described in Sentence(1) may be interrupted by
a) penetrations for windows, doors and services,
b) flashing,
c) nominally vertical furring or strapping, provided the furring or strapping does not make up more than 20%
of the drained and vented air space, and
d) insect screen, provided the screen allows for drainage and venting of the airspace.
3) Where a construction projects over the top of the drained and vented air space described in Clause(1)(a) or
over the drainage material described in Clause(1)(b), the air space or drainage material shall not be contiguous with
concealed spaces in the projecting construction.
4) Exterior walls exposed to precipitation shall be protected against precipitation ingress by an exterior cladding
assembly consisting of a first plane of protection and a second plane of protection, where such walls enclose spaces of
residential occupancy or spaces that directly serve spaces of residential occupancy.
5) Except as provided in Sentence(6), exterior walls exposed to precipitation shall be protected against
precipitation ingress by an exterior cladding assembly consisting of a first plane of protection and a second plane of
protection incorporating a capillary break, where
a) the number of degree-days is less than 3 400 and the moisture index is greater than 0.90, or
b) the number of degree-days is 3 400 or more, and the moisture index is greater than 1.00.
(SeeSentence1.1.3.1.(1) and AppendixC for information on the moisture index.)
6) In exterior walls described in Sentence(5), the first and second planes of protection need not incorporate a
capillary break, where
a) it can be shown that omitting the capillary break will not adversely affect the performance of the building
assemblies,
b) the building is an accessory building, or
c) the wall
i) is constructed of non-moisture-sensitive materials, and intersecting or supported floors are also
constructed of non-moisture-sensitive materials, or
ii) is constructed as a mass wall of sufficient thickness to minimize the transfer of moisture to the interior.
9.27.2.3. First and Second Planes of Protection
1) Where walls required to provide protection from precipitation comprise cladding assemblies with first and
second planes of protection,
a) the first plane of protection shall
i) consist of cladding with appropriate trim, accessory pieces and fasteners, and
ii) be designed and constructed to minimize the passage of rain and snow into the wall by minimizing holes
and managing precipitation ingress caused by the kinetic energy of raindrops, surface tension, capillarity,
gravity, and air pressure differences (seeSubsection9.27.4.),
b) the second plane of protection shall be designed and constructed to (seeSubsection9.27.3.)
i) intercept all rain and snow that gets past the first plane of protection, and
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British Columbia Building Code 2018 Division B
ii) effectively dissipate any rain or snow to the exterior, and
c) the protection provided by the first and second planes of protection shall be maintained
i) at wall penetrations created by the installation of components and services such as windows, doors,
ventilation ducts, piping, wiring and electrical outlets, and
ii) at the interface with other wall assemblies.
9.27.2.4. Protection of Cladding from Moisture
1) A clearance of not less than 200mm shall be provided between finished ground and cladding that is adversely
affected by moisture, such as untreated wood, plywood, OSB, waferboard and hardboard.
2) A clearance of not less than 50mm shall be provided between a roof surface and cladding that is adversely
affected by moisture, such as untreated wood, plywood, OSB, waferboard and hardboard.
9.27.3. Second Plane of Protection
9.27.3.1. Elements of the Second Plane of Protection
(SeeNoteA-9.27.3.1.)
1) The second plane of protection shall consist of a drainage plane having an appropriate inner boundary and
flashing to dissipate rainwater to the exterior.
2) Except for cladding systems conforming to Subsection9.27.13., the inner boundary of the drainage plane
shall comply with Articles9.27.3.2. to9.27.3.6.
3) The protection provided by the second plane of protection shall be maintained
a) at wall penetrations created by the installation of components and services such as windows, doors,
ventilation ducts, piping, wiring and electrical outlets, and
b) at the interface with other wall assemblies.
4) Flashing material and its installation shall comply with Articles9.27.3.7. and9.27.3.8.
9.27.3.2. Sheathing Membrane Material Standard
1) Sheathing membranes shall conform to the performance requirements of CAN/CGSB-51.32-M, “Sheathing,
Membrane, Breather Type.”
9.27.3.3. Required Sheathing Membrane and Installation
1) Except as provided in Articles9.27.3.4. to9.27.3.6., at least one layer of sheathing membrane shall be
applied beneath cladding.
2) Sheathing membrane required in Sentence(1) shall be applied so that joints are lapped not less than 100mm.
3) Where sheathing membrane required in Sentence(1) is applied horizontally, the upper sheets shall overlap
the lower sheets.
9.27.3.4. Insulating Sheathing in lieu of Sheathing Membrane
1) Where non-wood-based rigid exterior insulating sheathing, or exterior insulating sheathing with an integral
sheathing membrane is installed, a separate sheathing membrane is not required.
2) Where insulating sheathing is installed as provided in Sentence(1),
a) sheathing panels subject to moisture deterioration shall be sealed at all joints, and
b) the joints of sheathing panels not subject to moisture deterioration shall be
i) sealed at all joints, or
ii) lapped or tongue and groove, and detailed to ensure drainage of water to the exterior.
(SeeNoteA-9.27.3.4.(2).)
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.27.3.5. Sheathing Membranes in lieu of Sheathing
1) Except as provided in Article9.27.3.6., where no sheathing is used, at least 2 layers of sheathing membrane
shall be applied beneath the cladding. (SeeArticle9.23.17.1. and NoteA-9.27.3.5.(1).)
2) All joints in the sheathing membrane required in Sentence(1) shall occur over framing, and the membrane
shall be fastened to the framing with roofing nails or staples spaced not more than 150mm along the edges of the
outer layer of sheathing membrane.
3) Wall sheathing is permitted to be used in lieu of one layer of sheathing membrane required in Sentence(1),
and its thickness need not conform to Table9.23.17.2.-A.
9.27.3.6. Face Sealed Cladding
(SeeNoteA-9.27.3.6.)
1) Sheathing membrane is permitted to be omitted beneath cladding when the joints in the cladding are formed
to effectively prevent the passage of wind and rain in conformance with Sentences(2) or(3), as applicable.
2) Cladding consisting of sheets of plywood, hardboard, OSB, waferboard or fibre cement is considered to meet
the requirements of Sentence(1), provided the cladding is applied so that
a) all edges are directly supported by framing,
b) the vertical joints between adjacent sheets are sealed and
i) covered with battens,
ii) shiplapped, or
iii) otherwise matched to provide weathertight joints, and
c) the horizontal joints between adjacent sheets are sealed and
i) shiplapped, or
ii) otherwise matched to provide weathertight joints.
3) Metal siding consisting of sheets of metal is considered to meet the requirements of Sentence(1) where the
joints between sheets are of the locked-seam type.
9.27.3.7. Flashing Materials
1) Flashing shall consist of not less than
a) 1.73mm thick sheet lead,
b) 0.33mm thick galvanized steel,
c) 0.46mm thick copper,
d) 0.46mm thick zinc,
e) 0.48mm thick aluminum, or
f) 1.02mm thick vinyl.
9.27.3.8. Flashing Installation
1) Except as provided in Sentence(2), flashing shall be installed at
a) every horizontal junction between cladding elements,
b) every horizontal offset in the cladding, and
c) every horizontal line where the cladding substrates change and where
i) the substrates differ sufficiently for stresses to be concentrated along that line, or
ii) the installation of the cladding on the lower substrate may compromise the drainage of moisture from
behind the cladding above.
(SeeNoteA-9.27.3.8.(1).)
2) Flashing need not be installed as described in Sentence(1)
a) where the upper cladding elements overlap the lower cladding elements by not less than 25 mm,
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British Columbia Building Code 2018 Division B
b) where
i) the cladding above and below the joint is installed outboard of a drained and vented air space
(seeClause9.27.2.2.(1)(a)), and
ii) the horizontal detail is constructed so as to minimize the ingress of precipitation into the air space, or
c) at horizontal construction joints in stucco, where
i) the joint is finished with an expansion-contraction strip, and
ii) the cladding is installed outboard of a drained and vented air space (seeClause9.27.2.2.(1)(a)).
3) Flashing shall be installed over exterior wall openings where the vertical distance from the bottom of the eave
to the top of the trim is more than one-quarter of the horizontal overhang of the eave. (SeeNoteA-9.27.3.8.(3).)
4) Flashing described in Sentences(1) and(3) shall
a) extend not less than 50mm upward inboard of the sheathing membrane or sheathing installed in lieu of the
sheathing membrane (seeArticle9.27.3.4.),
b) have a slope of not less than 6% toward the exterior after the expected shrinkage of the building frame,
c) terminate at each end with an end-dam
i) with a height in millimetres not less than 25mm or 1/10 the value of the 1-in-5 driving rain wind
pressure in Pa, and
ii) at the height defined in Subclause(c)(i), extending to the face of the adjacent cladding,
d) lap not less than 10mm vertically over the building element below, and
e) terminate in a drip offset not less than 5mm outward from the outer face of the building element below.
(SeeNoteA-9.27.3.8.(4).)
5) Where the sills of windows and doors installed in exterior walls are not self-flashing, flashing shall be installed
between the underside of the window or door and the wall construction below. (SeeNoteA-9.27.3.8.(5).)
9.27.4. Sealants
9.27.4.1. Required Sealants
1) Sealant shall be provided where required to prevent the entry of water into the structure.
2) Sealant shall be provided between masonry, siding or stucco and the adjacent door and window frames or
trim, including sills, unless such locations are completely protected from the entry of rain.
3) Sealant shall be provided at vertical joints between different cladding materials unless the joint is suitably
lapped or flashed to prevent the entry of rain. (SeeArticles9.7.6.2.,9.20.13.12. and9.28.1.5.)
9.27.4.2. Materials
1) Sealants shall be
a) a non-hardening type suitable for exterior use,
b) selected for their ability to resist the effects of weathering, and
c) compatible with and adhere to the substrate to which they are applied.
(SeeNoteA-9.27.4.2.(1).)
2) Sealants shall conform to
a) ASTMC834, “Latex Sealants,”
b) ASTMC920, “Elastomeric Joint Sealants,”
c) ASTMC1184, “Structural Silicone Sealants,” or
d) ASTMC1311, “Solvent Release Sealants.”
3) Backer rod shall conform to ASTMC1330, “Cylindrical Sealant Backing for Use with Cold Liquid-Applied
Sealants.” (SeeNoteA-9.27.4.2.(1).)
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.27.5. Attachment of Cladding
9.27.5.1. Attachment
1) Except as permitted by Sentences(2) to(6), cladding shall be fastened to the framing members or furring
members, or to blocking between the framing members.
2) Vertical lumber and stucco lath or reinforcing are permitted to be attached to sheathing only where the
sheathing consists of not less than
a) 14.3mm lumber,
b) 12.5mm plywood, or
c) 12.5mm OSB or waferboard.
3) Vertically applied metal siding and wood shingles and shakes are permitted to be attached to the sheathing
only where the sheathing consists of not less than
a) 14.3mm lumber,
b) 7.5mm plywood, or
c) 7.5mm OSB or waferboard.
4) Where wood shingles or shakes are applied to sheathing which is not suitable for attaching the shingles or
shakes, the shingles or shakes are permitted to be attached to a wood lath not less than 38mm by 9.5mm thick
securely nailed to the framing and applied as described in Article9.27.7.5.
5) Reserved
.
6) Reserved
.
9.27.5.2. Blocking
1) Blocking for the attachment of cladding shall be not less than 38mm by 38mm lumber securely nailed to the
framing and spaced not more than 600mm o.c.
9.27.5.3. Furring
1) Except as permitted in Sentences9.27.5.1.(4) and(5), furring for the attachment of cladding shall be not less
than 19mm by 38mm lumber when applied over sheathing.
2) When applied without sheathing, furring referred to in Sentence(1) shall be not less than
a) 19mm by 64mm lumber on supports spaced not more than 400mm o.c., or
b) 19mm by 89mm lumber on supports spaced not more than 600mm o.c.
3) Furring referred to in Sentence(1) shall be
a) securely fastened to the framing, and
b) spaced not more than 600mm o.c.
9.27.5.4. Size and Spacing of Fasteners
1) Nail or staple size and spacing for the attachment of cladding and trim shall conform to Table9.27.5.4.
Table 9.27.5.4.
Attachment of Cladding
Forming Part of Sentence 9.27.5.4.(1)
Typeof Cladding
Minimum Nail or Staple
Length, mm
Minimum Number of Nails or
Staples
Maximum Nail or Staple Spacing,
mmo.c.
Wood trim 51 – 600
Lumber siding or horizontal siding made from sheet
material
51 – 600
Metal cladding 38 – 600 (nailed to framing)
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.27.5.5. Fastener Materials
1) Nails or staples for the attachment of cladding and wood trim shall be corrosion-resistant and shall be
compatible with the cladding material.
9.27.5.6. Expansion and Contraction
1) Fasteners for metal or vinyl cladding shall be positioned to permit expansion and contraction of the cladding.
9.27.5.7. Penetration of Fasteners
1) Fasteners for shakes and shingles shall penetrate through the nail-holding base or not less than 19mm into
the framing.
2) Fasteners for cladding other than that described in Sentence(1) shall penetrate through the nail-holding base
or not less than 25mm into the framing.
9.27.6. Lumber Siding
9.27.6.1. Materials
1) Lumber siding shall be sound, free of knot holes, loose knots, through checks or splits.
9.27.6.2. Thickness and Width
1) Drop, rustic, novelty, lapped board and vertical wood siding shall be not less than 14.3mm thick and not
more than 286mm wide.
2) Bevel siding shall be
a) not less than 5mm thick at the top, and
b) not less than
i) 12mm thick at the butt for siding 184mm or less in width, and
ii) 14.3mm thick at the butt for siding wider than 184mm.
3) Bevel siding shall be not more than 286mm wide.
9.27.6.3. Joints
1) Lumber siding shall prevent water from entering at the joints by the use of lapped or matched joints or by
vertical wood battens.
400 (nailed to sheathing only)
Wood shakes
up to 200 mm in width 51 2 –
over 200 mm in width 51 3 –
Wood shingles
200 mm in width 32 2 –
over 200 mm in width 32 3 –
Panel or sheet type cladding
up to 7 mm thick 38 – 150 (along edges)
more than 7 mm thick 51 – 300 (along intermediate supports)
Table 9.27.5.4. (continued)
Attachment of Cladding
Forming Part of Sentence 9.27.5.4.(1)
Typeof Cladding
Minimum Nail or Staple
Length, mm
Minimum Number of Nails or
Staples
Maximum Nail or Staple Spacing,
mmo.c.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Siding shall overlap not less than 1mm per 16mm width of lumber, but not less than
a) 9.5mm for matched siding,
b) 25mm for lapped bevel siding, or
c) 12mm for vertical battens.
9.27.7. Wood Shingles and Shakes
9.27.7.1. Materials
1) Shingles and shakes shall conform to
a) CSAO118.1, “Western Red Cedar Shakes and Shingles,” or
b) CSAO118.2, “Eastern White Cedar Shingles.”
2) Western cedar shakes shall be not less than No.1 or Handsplit grade, and western cedar shingles not less than
No.2 grade, except that No.3 grade may be used for undercoursing.
3) Eastern white cedar shingles shall be at least B(clear) grade, except that Cgrade may be used for the lower
course of double course applications.
9.27.7.2. Width
1) Shingles and shakes shall be not less than 65mm or more than 350mm wide.
9.27.7.3. Fasteners
1) Shingles or shakes shall be fastened with nails or staples located approximately 20mm from each edge and
not less than 25mm above the exposure line for single-course applications, or approximately 50mm above the butt
for double-course applications.
9.27.7.4. Offsetting of Joints
1) In single-course application, joints in succeeding courses shall be offset not less than 40mm so that joints in
any 2 of 3 consecutive courses are staggered.
2) In double-course application, joints in the outer course shall be offset from joints in the under-course by not
less than 40mm, and joints in succeeding courses shall be offset not less than 40mm.
9.27.7.5. Fastening to Lath
1) When lath is used with double-course application (see Sentence9.27.5.1.(4)), it shall be spaced according to
the exposure and securely fastened to the framing.
2) The butts of the under-course of the application referred to in Sentence(1) shall rest on the top edge of
the lath.
3) The outer course of the application referred to in Sentence(1) shall be fastened to the lath with nails of
sufficient length to penetrate through the lath.
4) The butts of the shingles or shakes shall be so located that they project not less than 12mm below the bottom
edge of the lath referred to in Sentence(1).
5) If wood lath is not used, the butts of the under-course shingles or shakes of the application referred to in
Sentence(1) shall be located 12mm above the butts of the outer course.
9.27.7.6. Exposure and Thickness
1) The exposure and butt thickness of shingles and shakes shall conform to Table9.27.7.6.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.27.8. Plywood
9.27.8.1. Material Standards
1) Plywood cladding shall be exterior type conforming to
a) ANSI/HPVA HP-1, “Hardwood and Decorative Plywood,”
b) CSAO121, “Douglas Fir Plywood,”
c) CSAO151, “Canadian Softwood Plywood,” or
d) CSAO153, “Poplar Plywood.”
9.27.8.2. Thickness
1) Plywood cladding shall be not less than 6mm thick when applied directly to sheathing.
2) When applied directly to framing or over furring strips, plywood cladding thickness shall conform to
Table9.27.8.2.
3) The thickness of grooved or textured plywood cladding shall be measured at the point of least thickness.
9.27.8.3. Edge Treatment
1) The edges of plywood cladding shall be treated with a suitable paint or sealer.
9.27.8.4. Panel Cladding
1) Plywood applied in panels shall have all edges supported.
2) Not less than a 2mm gap shall be provided between panels referred to in Sentence(1).
3) Vertical joints in cladding referred to in Sentence(1) shall be protected with batten strips or sealant when the
plywood joints are not matched.
4) Horizontal joints in cladding referred to in Sentence(1) shall be lapped not less than 25mm or shall be
suitably flashed.
9.27.8.5. Lapped Strip Siding
1) Plywood applied in horizontal lapped strips shall have not less than a 2mm gap provided at the butted ends,
which shall be caulked.
2) The horizontal joints of siding described in Sentence(1) shall be lapped not less than 25mm.
Table 9.27.7.6.
Exposure and Thickness of Wood Shingles and Shakes
Forming Part of Sentence 9.27.7.6.(1)
Shake or Shingle Length, mm
Maximum Exposure, mm
Minimum Butt Thickness, mm
Single Coursing Double Coursing
400 190 305 10
450 216 356 11
600 292 406 13
Table 9.27.8.2.
Minimum Plywood Cladding Thickness
Forming Part of Sentence 9.27.8.2.(2)
Spacing of Supports, mm
Minimum Thickness, mm
Face Grain Parallel to Supports Face Grain Right Angles to Supports
400 8 6
600 11 8
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
3) Wedges shall be inserted under all vertical butt joints and at all corners when horizontal lapped plywood is
applied without sheathing.
9.27.9. Hardboard
9.27.9.1. Material Standards
1) Factory-finished hardboard cladding shall conform to CAN/CGSB-11.5-M, “Hardboard, Precoated, Factory
Finished, for Exterior Cladding.”
2) Hardboard cladding that is not factory finished shall conform to Types 1, 2 or 5 in CAN/CGSB-11.3-M,
“Hardboard.”
9.27.9.2. Thickness
1) Type1 or 2 hardboard cladding shall be not less than
a) 6mm thick when applied over sheathing that provides continuous support, and
b) 7.5mm thick when applied over furring or framing members not more than 400mm o.c.
2) Type5 hardboard cladding shall be not less than 9mm thick when applied over sheathing that provides
continuous support or over furring or framing members spaced not more than 400mm o.c.
3) Where hardboard cladding is grooved, the grooves shall not extend more than 1.5mm into the minimum
required thickness. (SeeNoteA-9.27.9.2.(3).)
9.27.9.3. Panel Cladding
1) Hardboard cladding applied in panels shall have all edges supported with not less than a 5mm gap provided
between sheets.
2) Vertical joints in cladding described in Sentence(1) shall be protected with batten strips or sealant when the
joints are not matched.
3) Horizontal joints in cladding described in Sentence(1) shall be lapped not less than 25mm or shall be
suitably flashed.
9.27.9.4. Lapped Strip Siding
1) Hardboard applied in horizontal lapped strips shall have not less than a 5mm gap provided at the butted
ends, which shall be sealed or otherwise protected with suitable mouldings.
2) The horizontal joints of siding described in Sentence(1) shall overlap not less than 1mm per 16mm width
of siding board but not less than 9.5mm for matched joint siding or 25mm for lapped siding.
9.27.9.5. Clearance
1) Not less than 3mm clearance shall be provided between hardboard cladding and door or window frames.
9.27.10. OSB and Waferboard
9.27.10.1. Material Standard
1) OSB and waferboard cladding shall conform to CSAO437.0, “OSB and Waferboard.”
9.27.10.2. Thickness
1) OSB conforming to O-2 grade shall be not less than 6.0mm thick where applied directly to sheathing.
2) OSB conforming to O-2 grade applied directly to framing or over furring strips shall conform to the
thickness shown for plywood in Table9.27.8.2. (SeeNoteA-9.27.10.2.(2).)
3) OSB conforming to O-1 grade and waferboard conforming to R-1 grade shall be not less than 7.9mm thick
where applied directly to sheathing.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
4) Where applied directly to framing or over furring strips, OSB conforming to O-1 grade and waferboard
conforming to R-1 grade shall be not less than
a) 9.5mm thick on supports spaced not more than 400mm o.c., and
b) 12.7mm thick on supports spaced not more than 600mm o.c.
9.27.10.3. Panel Cladding
1) OSB and waferboard applied in panels shall have all edges supported and treated with a primer or sealer.
2) Not less than a 3mm gap shall be provided between sheets in cladding described in Sentence(1).
3) Vertical joints in cladding described in Sentence(1) shall be protected with batten strips or sealant when the
OSB and waferboard joints are not matched.
4) Horizontal joints in cladding described in Sentence(1) shall be lapped not less than 25mm or shall be
suitably flashed.
9.27.10.4. Clearance
1) Not less than a 3mm clearance shall be provided between OSB and waferboard cladding and door or
window frames.
9.27.11. Metal
9.27.11.1. Material Standards
1) Horizontal and vertical strip steel siding, including flashing and trim accessories, shall conform to
CAN/CGSB-93.4, “Galvanized Steel and Aluminum-Zinc Alloy Coated Steel Siding, Soffits and Fascia, Prefinished,
Residential.”
2) Steel sheet cladding shall have a minimum thickness of 0.3mm and conform to CAN/CGSB-93.3-M,
“Prefinished Galvanized and Aluminum-Zinc Alloy Steel Sheet for Residential Use.”
3) Horizontal and vertical strip aluminum siding, including flashing and trim accessories, shall conform to
CAN/CGSB-93.2-M, “Prefinished Aluminum Siding, Soffits, and Fascia, for Residential Use.”
(SeeNoteA-9.27.11.1.(3) and(4).)
4) Aluminum sheet cladding shall conform to CAN/CGSB-93.1-M, “Sheet, Aluminum Alloy, Prefinished,
Residential,” and shall have a thickness of not less than 0.58mm, except that siding supported by backing or
sheathing shall have a thickness of not less than 0.46mm. (SeeNoteA-9.27.11.1.(3) and (4).)
9.27.12. Vinyl Siding
9.27.12.1. Material Standard
1) Vinyl siding, including flashing and trim accessories, shall conform to CAN/CGSB-41.24, “Rigid Vinyl
Siding, Soffits andFascia.”
9.27.12.2. Attachment
1) The attachment of vinyl siding shall conform to the requirements in Subsection9.27.5. for metal siding.
9.27.13. Exterior Insulation Finish Systems
9.27.13.1. Application
1) Except as provided in Sentence(2), this Subsection applies to exterior insulation finish systems (EIFS) that
a) are covered in the scope of CAN/ULC-S716.1, “Exterior Insulation and Finish Systems (EIFS) - Materials
and Systems,”and
b) have a geometrically defined drainage cavity with a minimum cavity depth of 9.5
mm and an open area equal
to not less than 13% of the area of a full-size EIFS panel.
(SeeNoteA-9.27.13.1.(1).)
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) EIFS that are not covered by Sentence(1) shall comply with Part5.
9.27.13.2. Materials
1) The materials used in EIFS shall conform to CAN/ULC-S716.1, “Exterior Insulation and Finish Systems
(EIFS) – Materials and Systems.”
2) The substrate on which the EIFS is installed shall
a) be compatible with that particular system (seeNoteA-9.27.13.2.(2)(a)), and
b) comply with the structural requirements for sheathing materials stated in Section9.23.
9.27.13.3. Design and Installation
1) The design and installation of EIFS on the substrate described in Sentence9.27.13.2.(2) shall comply with
a) CAN/ULC-S716.2, “Exterior Insulation and Finish Systems (EIFS) – Installation of EIFS Components and
Water Resistive Barrier,” and
b) CAN/ULC-S716.3, “Exterior Insulation and Finish System (EIFS) – Design Application.”
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.28. Stucco
9.28.1. General
9.28.1.1. Sheathing beneath Stucco
1) Sheathing shall be provided beneath stucco applied over wood-frame walls except as permitted in
Article9.28.4.2.
2) Where applied beneath stucco, sheathing shall conform to Subsection9.23.17.
9.28.1.2. Lath and Reinforcing
1) Stucco lath or reinforcing shall be used to attach stucco to any substrate other than masonry.
2) Stucco lath or reinforcing shall be used to attach stucco to masonry where
a) the masonry is soft-burned tile or brick of less strength than the stucco, or
b) the masonry surface is not sound, clean and sufficiently rough to provide a good key.
3) Stucco applied over masonry chimneys shall be reinforced.
9.28.1.3. Concrete Masonry Units
1) Stucco finish shall not be applied over concrete masonry units less than one month old unless the units have
been cured by the autoclave process.
9.28.1.4. Clearance over Ground Level
1) Stucco shall be not less than 200mm above finished ground level except when it is applied over concrete
or masonry.
9.28.1.5. Flashing and Caulking
1) Flashing and caulking used with stucco shall conform to Subsections9.27.3. and 9.27.4., except that if
aluminum flashing is used, it shall be separated from the stucco by an impervious membrane or coating.
(SeeArticle9.7.6.2. for caulking around window frames.)
9.28.2. Stucco Materials
9.28.2.1. Portland Cement
1) Portland cement shall conform to CSAA3001, “Cementitious Materials for Use in Concrete.”
9.28.2.2. Aggregate
1) Aggregate shall be clean, well-graded natural sand or sand manufactured from crushed stone, gravel or
air-cooled blast furnace slag and shall contain no significant amounts of deleterious material.
2) Aggregate grading shall conform to Table9.28.2.2.
Table 9.28.2.2.
Aggregate Grading for Stucco
Forming Part of Sentence 9.28.2.2.(2)
Sieve Sizes, mm
% Aggregate Passing Sieve
Maximum Minimum
4 – 100
2–90
19060
0.5 60 45
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.28.2.3. Water
1) Water shall be clean and free of significant amounts of deleterious material.
9.28.3. Fasteners
9.28.3.1. Materials
1) Fasteners for stucco lath or reinforcing shall be corrosion-resistant and of a material other than aluminum.
9.28.3.2. Nails and Staples
1) Nails for stucco lath or reinforcing shall be not less than 3.2mm diam with a head diameter of not less
than 11.1mm.
2) Staples for stucco lath or reinforcing shall be not less than 1.5mm diam or thickness.
3) Staples and nails for attaching stucco lath or reinforcing to vertical surfaces shall be of sufficient length to
penetrate 25mm into framing members or to the full depth of the sheathing where the sheathing is used for
attachment.
4) On horizontal surfaces nails for stucco lath or reinforcing shall be not less than 38mm long.
9.28.4. Stucco Lath
9.28.4.1. Materials
1) Rib lath or expanded metal stucco mesh shall be
a) copper-alloy steel coated with rust-inhibitive paint after fabrication, or
b) galvanized.
2) Woven or welded wire mesh shall be galvanized.
9.28.4.2. No Sheathing Required
1) Sheathing need not be provided beneath stucco where not less than 1.19mm diam galvanized wire is applied
horizontally to the framing at vertical intervals of not more than 150mm, or where paper-backed welded wire metal
lath is used.
9.28.4.3. Stucco Lath Specifications
1) Stucco lath shall conform to Table9.28.4.3.
0.25 30 10
0.125 5 –
Table 9.28.2.2. (continued)
Aggregate Grading for Stucco
Forming Part of Sentence 9.28.2.2.(2)
Sieve Sizes, mm
% Aggregate Passing Sieve
Maximum Minimum
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.28.4.4. Self-Furring Devices
1) Stucco lath shall be held not less than 6mm away from the backing by means of suitable self-furring devices.
9.28.4.5. Application of Stucco Lath
1) Stucco lath shall be applied with the long dimension horizontal.
2) Horizontal and vertical joints in stucco lath shall be lapped not less than 50mm.
3) End joints of stucco lath shall be staggered and shall occur over framing members.
4) External corners of stucco lath shall be reinforced with a vertical strip of lath or reinforcing extending not less
than 150mm on both sides of the corner, or the lath or reinforcing shall extend around corners not less than
150mm.
9.28.4.6. Fastening
1) Stucco lath shall be fastened in conformance with Subsection9.27.5.
2) Fasteners on vertical surfaces shall be spaced not more than
a) 150mm o.c. vertically and 400mm o.c. horizontally, or
b) 100mm o.c. vertically and 600mm o.c. horizontally.
3) Nailing patterns other than those required in Sentence(2) are permitted to be used provided there are at
least 20 fasteners per square metre of wall surface.
4) Fasteners on horizontal surfaces shall be spaced not more than
a) 150mm o.c. along the framing members when members are spaced not more than 400mm o.c., and
b) 100mm o.c. along members when members are spaced not more than 600mm o.c.
9.28.5. Stucco Mixes
9.28.5.1. Mixes
1) Stucco mixes shall conform to Table9.28.5.1.
Table 9.28.4.3.
Stucco Lath
Forming Part of Sentence 9.28.4.3.(1)
Location Type of Lath Minimum Diam of Wire, mm Maximum Mesh Opening Minimum Mass, kg/m
2
Vertical surfaces
Welded or woven wire
1.15 25 mm –
1.30 38 mm –
1.50 51 mm –
Stucco mesh reinforcing
(expanded metal)
– 25.8 cm
2
0.98
Horizontal surfaces
(1)
9.5 mm rib lath – – 1.84
Cedar lath – – –
Notes to Table9.28.4.3.:
(1) See Note A-Table 9.28.4.3.
(2) Wire with other than a circular cross-section is acceptable if its cross-sectional area is equal to or greater than that of the wire listed.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
9.28.5.2. Pigments
1) Pigment if used shall consist of pure mineral oxides inert to the action of sun, lime and cement.
2) Pigment shall not exceed 6% of the Portland cement by weight.
9.28.5.3. Mixing
1) Materials shall be thoroughly mixed before and after water is added.
2) Stucco shall be applied not later than 3h after the initial mixing.
9.28.6. Stucco Application
9.28.6.1. Low Temperature Conditions
1) The base for stucco shall be maintained above freezing.
2) Stucco shall be maintained at a temperature of not less than 10°C during application, and for not less than
48 h afterwards.
9.28.6.2. Number of Coats and Total Thickness
1) Stucco shall be applied with at least2 basecoats and one finish coat, providing a total thickness of not less
than 15mm, measured from the face of the lath or the face of the masonry where no lath is used.
9.28.6.3. First Coat
1) The first coat shall be not less than 6mm thick, measured from the face of the lath or masonry, fully
embedding the lath.
2) The surface of the first coat shall be scored to provide a key with the second coat.
9.28.6.4. Second Coat
1) The second coat shall be not less than 6mm thick.
2) The surface of the second coat shall be lightly roughened to provide a key with the finish coat if the finish
coat is other than stone dash.
9.28.6.5. Finish Coat
1) When the finish coat is other than stone dash, the base shall be dampened but not saturated before the finish
coat is applied.
2) The thickness of the finish coat shall be not less than 3mm.
3) When a stone dash finish is used, the stone shall be partially embedded in the second coat before the second
coat starts to set or stiffen.
Table 9.28.5.1.
Stucco Mixes
Forming Part of Sentence 9.28.5.1.(1)
Materials, volume
Portland Cement Masonry Cement Lime Aggregate
1 – 0.25 to 1
3.25 to 4 parts per part of cementitious material
11–
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
Section 9.29. Interior Wall and Ceiling Finishes
9.29.1. General
9.29.1.1. Fire Protection and Sound Control
1) A wall or ceiling finish shall also conform to the appropriate requirements in Sections9.10. and 9.11.,
in addition to the requirements in this Section.
9.29.2. Waterproof Wall Finish
9.29.2.1. Where Required
1) Waterproof finish shall be provided to a height of not less than
a) 1.8m above the floor in shower stalls,
b) 1.2m above the rims of bathtubs equipped with showers, and
c) 400mm above the rims of bathtubs not equipped with showers.
9.29.2.2. Materials
1) Waterproof finish shall consist of ceramic, plastic or metal tile, sheet vinyl, tempered hardboard, laminated
thermosetting decorative sheets or linoleum.
9.29.3. Wood Furring
9.29.3.1. Size and Spacing of Furring
1) Wood furring for the attachment of wall and ceiling finishes shall conform to Table9.29.3.1.
9.29.3.2. Fastening
1) Furring shall be fastened to the framing or to wood blocks with not less than 51mm nails.
9.29.4. Plastering
9.29.4.1. Application
1) Application of plaster wall and ceiling finishes, including installation of metal or gypsum lath, shall conform
to CSAA82.30-M, “Interior Furring, Lathing and Gypsum Plastering.”
9.29.5. Gypsum Board Finish (Taped Joints)
9.29.5.1. Application
1) The requirements for application of gypsum board in this Subsection apply to the single layer application of
gypsum board to wood furring or framing using nails or screws.
Table 9.29.3.1.
Size and Spacing of Furring
Forming Part of Sentence 9.29.3.1.(1)
Maximum Spacing of Furring,mm
Minimum Size of Furring,mm
Maximum Spacing of Furring Supports
Continuous Supports 400mm o.c. 600mm o.c.
300 19 × 38 19 × 38 19 × 64
400 19 × 38 19 × 38 19 × 64
600 19 × 38 19 × 64 19 × 89
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Gypsum board applications not described in this Subsection shall conform to CSAA82.31-M, “Gypsum
Board Application.”
9.29.5.2. Materials
1) Gypsum products shall conform to
a) ASTM C 1178/C 1178M, “Coated Glass Mat Water-Resistant Gypsum Backing Panel,” or
b) ASTM C 1396/C 1396M, “Gypsum Board,” except that the flame-spread rating of gypsum board shall be
determined in accordance with CAN/ULC-S102, “Test for Surface Burning Characteristics of Building
Materials and Assemblies.”
9.29.5.3. Maximum Spacing of Supports
1) Maximum spacing of supports for gypsum board applied as a single layer shall conform to Table9.29.5.3.
9.29.5.4. Support of Insulation
1) Gypsum board supporting insulation shall be not less than 12.7mm thick.
9.29.5.5. Length of Fasteners
1) The length of fasteners for gypsum board shall conform to Table9.29.5.5., except that lesser depths of
penetration are permitted for assemblies required to have a fire-resistance rating provided it can be shown, on the basis
of fire tests, that such depths are adequate for the required rating.
Table 9.29.5.3.
Spacing of Supports for Gypsum Board
Forming Part of Sentence 9.29.5.3.(1)
Thickness,mm
Orientation of Board to
Framing
Maximum Spacing of Supports, mm o.c.
Walls
Ceilings
Painted Finish Water-Based Texture Finish
Gypsum board conforming to Sentence 9.29.5.2.(1) (except Sections 9 and 12 of ASTM C 1396/C 1396M)
9.5 parallel – – –
perpendicular 400 400 –
12.7 parallel 600 400 –
perpendicular 600 600 400
15.9 parallel 600 400 –
perpendicular 600 600 600
Gypsum ceiling board conforming to Clause 9.29.5.2.(1)(b) (only Section 12 of ASTM C 1396/C 1396M)
12.7 parallel 600 400 –
perpendicular 600 600 600
Table 9.29.5.5.
Fastener Penetration into Wood Supports
Forming Part of Sentence 9.29.5.5.(1)
Required Fire-Resistance Rating
of Assembly
Minimum Penetration, mm
Walls Ceilings
Nails Screws Nails Screws
Not required 20 15 20 15
45 min 20 20 30 30
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.29.5.6. Nails
1) Nails for fastening gypsum board to wood supports shall conform to
a) ASTM F 1667, “Driven Fasteners: Nails, Spikes, and Staples,” or
b) CSAB111, “Wire Nails, Spikes and Staples.”
9.29.5.7. Screws
1) Screws for fastening gypsum board to wood supports shall conform to ASTM C 1002, “Steel Self-Piercing
Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Wood Studs or Steel Studs.”
9.29.5.8. Spacing of Nails
1) For single-layer application on a ceiling, nails shall be spaced
a) not more than 180mm o.c. on ceiling supports, or
b) every 300mm o.c. along ceiling supports, in pairs about 50mm apart.
2) Where the ceiling sheets are supported by the wall sheets around the perimeter of the ceiling, this support
may be considered as equivalent to nailing at this location.
3) Except as required by Sentence(4), for single-layer application on walls, nails shall be spaced
a) not more than 200mm o.c. on vertical wall supports, or
b) every 300mm o.c. along vertical wall supports, in pairs about 50mm apart.
4) For single-layer application on walls, where gypsum board provides required bracing in braced wall panels,
lateral support for studs, or fire protection, nails shall be spaced not more than 200mm o.c. on
a) vertical wall supports, and
b) top and bottom plates.
(SeeArticle9.23.10.2. and Section9.10.)
5) The uppermost nails on vertical wall supports shall be not more than 200mm below the ceiling.
6) Nails shall be located not less than 10mm from the side or edge of the board.
7) Nails shall be driven so that the heads do not puncture the paper.
9.29.5.9. Spacing of Screws
1) For single-layer application on a ceiling, screws shall be spaced not more than 300mm o.c. on
ceiling supports.
2) Where the ceiling sheets are supported by the wall sheets around the perimeter of the ceiling, this support
may be considered as equivalent to screwing at this location.
3) Except as required by Sentence(4), for single-layer application on walls, screws shall be spaced
a) not more than 300mm o.c. on vertical wall supports where the supports are more than 400mm o.c., or
b) not more than 400mm o.c. on vertical wall supports where the supports are not more than 400mm o.c.
1 h 20 20 45 45
1.5 h 20 20 60 60
Table 9.29.5.5. (continued)
Fastener Penetration into Wood Supports
Forming Part of Sentence 9.29.5.5.(1)
Required Fire-Resistance Rating
of Assembly
Minimum Penetration, mm
Walls Ceilings
Nails Screws Nails Screws
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
4) Except as provided in Sentence(5), for single-layer application on walls, where gypsum board provides
required bracing in braced wall panels, lateral support for studs, or fire protection, screws shall be spaced not more
than 300mmo.c. on
a) vertical wall supports, and
b) top and bottom plates.
(SeeArticle9.23.10.2. and Section9.10.)
5) Where a fire-resistance rating is determined based on Table9.10.3.1.-A, Sentence(4) need not apply for the
purpose of fire protection.
6) Screws shall be located not less than 10mm from the edge of the board.
7) Screws shall be driven so that the heads do not puncture the paper.
9.29.5.10. Low Temperature Conditions
1) In cold weather, heat shall be provided to maintain a temperature not below 10°C for 48h prior to taping
and finishing and maintained for not less than 48h thereafter.
9.29.6. Plywood Finish
9.29.6.1. Thickness
1) Except as provided in Sentences(2) and(3), the minimum thickness of plywood interior finish shall conform
to Table9.29.6.1.
2) A manufacturing tolerance of −0.4mm may be applied to the thicknesses listed in Table9.29.6.1.
3) No minimum thickness is required where plywood is applied over continuous backing.
9.29.6.2. Grooved Plywood
1) Except as permitted in Sentence(2), where plywood for interior finish is grooved, the grooves shall not
extend through the face ply and into the plies below the face ply unless the groove is supported by framing or furring.
2) If the grain of the face ply is at right angles to the supporting members, the groove is permitted to extend into
plies below the face ply provided the thickness of the plywood exceeds the value shown in Table9.29.6.1. by an
amount equal to not less than the depth of penetration of the grooves into the plies below the face ply.
9.29.6.3. Nails and Staples
1) Except as provided in Sentence(2), nails for attaching plywood finishes shall not be less than 38mm casing
or finishing nails spaced not more than 150mm o.c. along edge supports and 300mm o.c. along intermediate
supports, except that staples providing equivalent lateral resistance may also be used.
2) Where plywood finish provides required bracing in braced wall panels, the plywood shall be fastened in
accordance with the fastening requirements for sheathing stated in Sentence9.23.3.5.(2).
9.29.6.4. Edge Support
1) All plywood edges shall be supported by furring, blocking or framing.
Table 9.29.6.1.
Thickness of Plywood Interior Finish
Forming Part of Articles 9.29.6.1. and 9.29.6.2.
Maximum Spacing
of Supports, mm o.c.
Minimum Thickness, mm
(1)
On Supports with no Horizontal Blocking On Supports with Blocking at Vertical Intervals notExceeding 1.2m
400 4.7 4.0
600 8.0 4.7
Notes to Table9.29.6.1.:
(1) Thickness limits shall apply to the net effective thickness (NET) of grooved, striated, textured and/or embossed panels and to the actual thickness of flat panels.
Division B: Acceptable Solutions Part 9 – Housing and Small Buildings
British Columbia Building Code 2018 Division B
9.29.7. Hardboard Finish
9.29.7.1. Material Standard
1) Hardboard shall conform to CAN/CGSB-11.3-M, “Hardboard.”
9.29.7.2. Thickness
1) Hardboard shall be not less than
a) 3mm thick where applied over continuous backing,
b) 6mm thick when applied over supports spaced not more than 400mm o.c., and
c) 9mm thick when applied over supports spaced not more than 600mm o.c.
9.29.7.3. Nails
1) Nails for fastening hardboard shall be casing or finishing nails not less than 38mm long, spaced not more
than 150mm o.c. along edge supports and 300mm o.c. along intermediate supports.
9.29.7.4. Edge Support
1) All hardboard edges shall be supported by furring, blocking or framing where the backing is not continuous.
9.29.8. Insulating Fibreboard Finish
9.29.8.1. Material Standard
1) Insulating fibreboard shall conform to CAN/ULC-S706, “Wood Fibre Insulating Boards for Buildings.”
9.29.8.2. Thickness
1) Insulating fibreboard sheets shall be not less than 11.1mm thick on supports not more than 400mm o.c.
2) Insulating fibreboard tile shall be not less than 12.7mm thick on supports spaced not more than
400mm o.c.
9.29.8.3. Nails
1) Nails for fastening fibreboard sheets shall be not less than 2.6mm shank diameter casing or finishing nails of
sufficient length to penetrate not less than 20mm into the supports.
2) Nails shall be spaced not more than 100mm o.c. along edge supports and 200mm o.c. along
intermediate supports.
9.29.8.4. Edge Support
1) All fibreboard edges shall be supported by blocking, furring or framing.
9.29.9. Particleboard, OSB or Waferboard Finish
9.29.9.1. Material Standard
1) Particleboard finish shall conform to ANSIA208.1, “Particleboard.”
2) OSB or waferboard finish shall conform to
a) CSAO325, “Construction Sheathing,” or
b) CSAO437.0, “OSB and Waferboard.”
9.29.9.2. Minimum Thickness
1) Except as provided in Sentences(2) and(3), the minimum thickness of O-2 grade OSB used as an interior
finish shall conform to that shown for plywood in Table9.29.6.1.
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Thicknesses listed in Table9.29.6.1. shall permit a manufacturing tolerance of −0.4mm.
3) No minimum thickness is required where O-2 grade OSB is applied over continuous backing.
4) OSB conforming to O-1 grade, waferboard conforming to R-1 grade and particleboard shall be
a) not less than 6.35mm thick on supports not more than 400mm o.c.,
b) not less than 9.5mm thick on supports not more than 600mm o.c., and
c) not less than 6.35mm thick on supports not more than 600mm o.c. in walls where blocking is provided at
midwall height.
5) OSB conforming to CSAO325, “Construction Sheathing,” shall meet the minimum panel mark of
a) W16, on supports not more than 400mm o.c.,
b) W24, on supports not more than 600mm o.c., and
c) W16, on supports not more than 600mm o.c. where blocking is provided at mid-wall height.
9.29.9.3. Nails
1) Except as provided in Sentence(2), nails for fastening particleboard, OSB or waferboard shall be not less than
38mm casing or finishing nails spaced not more than 150mm o.c. along edge supports and 300mmo.c. along
intermediate supports.
2) Where OSB or waferboard provides required bracing in braced wall panels, the OSB or waferboard shall be
fastened in accordance with the fastening requirements for sheathing stated in Sentence9.23.3.5.(2).
9.29.9.4. Edge Support
1) All particleboard, OSB or waferboard edges shall be supported by furring, blocking or framing.
9.29.10. Wall Tile Finish
9.29.10.1. Tile Application
1) Ceramic tile shall be set in a mortar base or applied with an adhesive.
2) Plastic tile shall be applied with an adhesive.
9.29.10.2. Mortar Base
1) When ceramic tile is applied to a mortar base the cementitious material shall consist of one part Portland
cement to not more than one-quarter part lime by volume.
2) The cementitious material described in Sentence(1) shall be mixed with not less than 3 nor more than
5parts of aggregate per part of cementitious material by volume.
3) Mortar shall be applied over metal lath or masonry.
4) Ceramic tile applied to a mortar base shall be thoroughly soaked and pressed into place forcing the mortar
into the joints while the tile is wet.
9.29.10.3. Adhesives
1) Adhesives to attach ceramic and plastic tile shall be applied to the finish coat or brown coat of plaster that has
been steel-trowelled to an even surface or to gypsum board or to masonry provided the masonry has an even surface.
9.29.10.4. Moisture-Resistant Backing
1) Ceramic and plastic tile installed on walls around bathtubs or showers shall be applied over moisture-resistant
backing.
9.29.10.5. Joints between Tiles and Bathtub
1) The joints between wall tiles and a bathtub shall be suitably caulked with material conforming to
CAN/CGSB-19.22-M, “Mildew-Resistant Sealing Compound for Tubs and Tiles.”
Part 9 – Housing and Small Buildings Division B: Acceptable Solutions
Division B
2) Thicknesses listed in Table9.29.6.1. shall permit a manufacturing tolerance of −0.4mm.
3) No minimum thickness is required where O-2 grade OSB is applied over continuous backing.
4) OSB conforming to O-1 grade, waferboard conforming to R-1 grade and particleboard shall be
a) not less than 6.35mm thick on supports not more than 400mm o.c.,
b) not less than 9.5mm thick on supports not more than 600mm o.c., and
c) not less than 6.35mm thick on supports not more than 600mm o.c. in walls where blocking is provided at
midwall height.
5) OSB conforming to CSAO325, “Construction Sheathing,” shall meet the minimum panel mark of
a) W16, on supports not more than 400mm o.c.,
b) W24, on supports not more than 600mm o.c., and
c) W16, on supports not more than 600mm o.c. where blocking is provided at mid-wall height.
9.29.9.3. Nails
1) Except as provided in Sentence(2), nails for fastening particleboard, OSB or waferboard shall be not less than
38mm casing or finishing nails spaced not more than 150mm o.c. along edge supports and 300mmo.c. along
intermediate supports.
2) Where OSB or waferboard provides required bracing in braced wall panels, the OSB or waferboard shall be
fastened in accordance with the fastening requirements for sheathing stated in Sentence9.23.3.5.(2).
9.29.9.4. Edge Support
1) All particleboard, OSB or waferboard edges shall be supported by furring, blocking or framing.
9.29.10. Wall Tile Finish
9.29.10.1. Tile Application
1) Ceramic tile shall be set in a mortar base or applied with an adhesive.
2) Plastic tile shall be applied with an adhesive.
9.29.10.2. Mortar Base
1) When ceramic tile is applied to a mortar base the cementitious material shall consist of one part Portland
cement to not more than one-quarter part lime by volume.
2) The cementitious material described in Sentence(1) shall be mixed with not less than 3 nor more than
5parts of aggregate per part of cementitious material by volume.
3) Mortar shall be applied over metal lath or masonry.
4) Ceramic tile applied to a mortar base shall be thoroughly soaked and pressed into place forcing the mortar
into the joints while the tile is wet.
9.29.10.3. Adhesives
1) Adhesives to attach ceramic and plastic tile shall be applied to the finish coat or brown coat of plaster that has
been steel-trowelled to an even surface or to gypsum board or to masonry provided the masonry has an even surface.
9.29.10.4. Moisture-Resistant Backing
1) Ceramic and plastic tile installed on walls around bathtubs or showers shall be applied over moisture-resistant
backing.
9.29.10.5. Joints between Tiles and Bathtub
1) The joints between wall tiles and a bathtub shall be suitably caulked with material conforming to
CAN/CGSB-19.22-M, “Mildew-Resistant Sealing Compound for Tubs and Tiles.”