The Ontario Building Code | Foundation Wall Thickness and Required Lateral Support
9.15.4.2. foundation Wall Thickness and Required Lateral support
(1) Except as required in Sentence (2), the thickness of foundation walls made of unreinforced concrete block or solid concrete and subject to lateral earth pressure shall conform to Table 9.15.4.2.A. for walls not exceeding 3.0 m in unsupported height.
Table 9.15.4.2.A.
Thickness of Solid Concrete and Unreinforced Concrete Block foundation Walls
Forming Part of Sentence 9.15.4.2.(1)
| Item | Column 1 | Column 2 | Column 3 | Column 4 | Column 5 | Column 6 | |
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| Type of foundation Wall | Minimum wall Thickness, mm | Maximum Height of Finish Ground Above basement floor or Crawl Space Ground Cover, m | ||||
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| Height of foundation Wall Laterally Unsupported at the Top(1)(2) | Height of foundation Wall Laterally supported at the Top(1)(2) | |||
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| ≤3.0 m | ≤2.5 m | >2.5 m and ≤2.75 m | >2.75 m and ≤3.0 m | |
| 1. | Solid concrete, 15 MPa min. strength | 150 | 0.8 | 1.5 | 1.5 | 1.4 | |
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| 200 | 1.2 | 2.15 | 2.15 | 2.1 | |
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| 250 | 1.4 | 2.3 | 2.6 | 2.5 | |
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| 300 | 1.5 | 2.3 | 2.6 | 2.85 | |
| 2. | Solid concrete, 20 MPa min. strength | 150 | 0.8 | 1.8 | 1.6 | 1.6 | |
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| 200 | 1.2 | 2.3 | 2.3 | 2.2 | |
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| 250 | 1.4 | 2.3 | 2.6 | 2.85 | |
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| 300 | 1.5 | 2.3 | 2.6 | 2.85 | |
| 3. | Unreinforced concrete block | 140 | 0.6 | 0.8 | - | - | |
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| 190 | 0.9 | 1.2 | (3) | (3) | |
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| 240 | 1.2 | 1.8 | (3) | (3) | |
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| 290 | 1.4 | 2.2 | - | - | |
Notes to Table 9.15.4.2.A.:
(1) See Article 9.15.4.3.
(2) See Article 9.15.4.6.
(3) See Table 9.15.4.2.B.
(2) The thickness of concrete in flat insulating concrete form foundationwalls shall be not less than the greater of,
(a) 140 mm, or
(b) the thickness of the concrete in the wall above.
(3) foundation walls made of flat insulating concrete form units shall be laterally supported at the top and at the bottom.
(4) The thickness and reinforcing of foundation walls made of reinforced concrete block and subject to lateral earth pressure shall conform to Table 9.15.4.2.B. and Sentences (5) to (8) where,
(a) the walls are laterally supported at the top,
(b) average stable soils are encountered, and
(c) wind loads on the exposed portion of the foundation are no greater than 0.70 kPa.
Table 9.15.4.2.B.
Reinforced Concrete Block foundation Walls Laterally supported at the Top(1)
Forming Part of Sentence 9.15.4.2.(4)
| Item | Column 1 | Column 2 | Column 3 | Column 4 | Column 5 | Column 6 | Column 7 |
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| Maximum Height of | Size and Spacing of Continuous Vertical Reinforcement, M at mm o.c. |
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| Finished Ground above | 190 mm Minimum wall Thickness |
| 240 mm Minimum wall Thickness |
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| foundation Wall Height |
| foundation Wall Height |
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| Space Ground Cover, m(2) |
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| 1. | 0.8 | (3) | (3) | (3) | (3) | (3) | (3) |
| 2. | 1.0 | (3) | 1-15M at 1 800 | 1-15M at 1 800 | (3) | (3) | (3) |
| 3. | 1.2 | (3) | 1-15M at 1 600 | 1-15M at 1 600 | (3) | 1-20M at 2 000 | 1-20M at 2 000 |
| 4. | 1.4 | 1-15M at 1 600 | 1-15M at 1 600 | 1-15M at 1 600 | (3) | 1-20M at 1 800 | 1-20M at 1 800 |
| 5. | 1.6 | 1-15M at 1 400 | 1-15M at 1 400 | 1-15M at 1 400 | (3) | 1-20M at 1 600 | 1-20M at 1 600 |
| 6. | 1.8 | 1-15M at 1 400 | 1-15M at 1 400 | 1-15M at 1 200 | (3) | 1-20M at 1 600 | 1-20M at 1 600 |
| 7. | 2.0 | 1-15M at 1 200 | 1-15M at 1 000 or 1-20M at 1 200 | 2-15M at 1 200 | 1-20M at 1 600 | 1-20M at 1 600 | 1-20M at 1 600 |
| 8. | 2.2 | 2-15M at 1 200 | 2-15M at 1 000 | 2-15M at 1 000 | 1-20M at 1 400 | 1-20M at 1 400 | 1-20M at 1 400 |
| 9. | 2.4 | 2-15M at 1 000 | 2-15M at 1 000 | 2-15M at 800 | 1-20M at 1 400 | 1-20M at 1 400 | 1-20M at 1 200 |
| 10. | 2.6 | N/A | 2-15M at 800 or 1-25M at 1 000 | 2-15M at 800 or 1-25M at 1 000 | N/A | 1-20M at 1 000 | 1-20M at 1 000 |
| 11. | 2.8 | N/A | N/A | 1-20M at 600 | N/A | N/A | 1-20M at 800 or 2-15M at 1 000 |
| 12. | 3.0 | N/A | N/A | 1-20M at 400 or 1-25M at 600 | N/A | N/A | 2-15M at 800 |
Notes to Table 9.15.4.2.B.:
(1) See Article 9.15.4.3.
(2) See Article 9.15.4.6.
(3) No reinforcement required.
(5) For concrete block walls required to be reinforced, continuous vertical reinforcement shall,
(a) be provided at wall corners, wall ends, wall intersections, at changes in wall height, at the jambs of all openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings and at movement joints,
(b) extend from the top of the footing to the top of the foundation wall, and
(c) where foundationwalls are laterally supported at the top, have not less than 50 mm embedment into the footing, if the floor slab does not provide lateral support at the wall base.
(6) For concrete block walls required to be reinforced, a continuous horizontal bond beam containing at least one 15M bar shall be installed,
(a) along the top of the wall,
(b) at the sill and head of all openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings greater than 1.2 m in width, and
(c) at structurally connected floors.
(7) In concrete block walls required to be reinforced, all vertical bar reinforcement shall be installed along the centre line of the wall.
(8) In concrete block walls required to be reinforced, ladder or truss type lateral reinforcement not less than 3.8 mm in diameter (No. 9 ASWG) shall be installed in the bed joint of every second masonry course.