9.15.4. Foundation Walls — OBC 2006 (in force 31 December 2006 to 1 January 2014)

9.15.4. — Foundation Walls

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9.15.4.1. — Permanent Form Material

(1) Insulating concrete form units shall be manufactured of polystyrene conforming to the performance requirements of CAN/ULC-S701, “Thermal Insulation, Polystyrene, Boards and Pipe Covering”, for Type 2, 3 or 4 polystyrene.

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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 2.5 m in unsupported height.

(2) The thickness of concrete in flat insulating concrete form foundation walls 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) Where average stable soils are encountered and wind loads on the exposed portion of the foundation are no greater than 0.70 kPa, 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 (10).

(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 and at movement joints,

(b) extend from the top of the footing to the top of the foundation wall,

(c) where foundation walls are laterally unsupported at the top, have not less than 600 mm embedment into the footing, and

(d) where foundation walls 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) Where foundation walls are laterally unsupported, the footing shall be designed according to Part 4 to resist overturning and sliding, if the maximum height of finished ground above the basement floor or crawl space ground cover exceeds 1.50 m.

(7) At the base of concrete block walls required to be reinforced and where the height of finished ground above the basement floor or crawl space ground cover exceeds 2.0 m, not less than one 15M intermediate vertical bar reinforcement shall be installed midway between adjacent continuous vertical reinforcement, and shall,

(a) extend to not less than 600 mm above the top of the footing, and

(b) have not less than 50 mm embedment into the footing, if the floor slab does not provide lateral support at the wall base.

(8) 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 greater than 1.20 m in width, and

(c) at structurally connected floors.

(9) In concrete block walls required to be reinforced, all vertical bar reinforcement shall be installed along the centre line of the wall.

(10) In concrete block walls required to be reinforced, ladder or truss type lateral reinforcement not less than 3.8 mm (No. 9 ASWG) shall be installed in the bed joint of every second masonry course.

Editor's note

As filed in O. Reg. 350/06, Table 9.15.4.2.B. heads its second column 'Colun 2' — an apparent typographical error for 'Column 2' — italicizes the headings of Columns 3 to 6, leaves the heading of the table's notes unbolded, and numbers the notes '(1)', '(2)' and '(3)'. The current e-Laws consolidation corrects the spelling to 'Column 2', removes the italics, bolds the notes heading, and renders the note numbers as superscripts, with no amending regulation making any of these changes. This map preserves the table as filed.

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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)


Column 1	Column 2	Column 3	Column 4
Type of Foundation Wall	Minimum Wall Thickness, Mm	Maximum Height of Finish Ground Above Basement Floor or Crawl Space Ground Cover, m
Type of Foundation Wall	Minimum Wall Thickness, Mm	Foundation Wall Laterally Unsupported at the Top⁽¹⁾	Foundation Wall Laterally Supported at the Top⁽¹⁾
Solid concrete, 15 Mpa min. strength	150	0.8	1.5
	200	1.2	2.15
	250	1.4	2.3
	300	1.5	2.3
Solid concrete, 20 Mpa min. strength	150	0.8	1.8
	200	1.2	2.3
	250	1.4	2.3
	300	1.5	2.3
Unreinforced Concrete Block	140	0.6	0.8
	190	0.9	1.2
	240	1.2	1.8
	290	1.4	2.2

Note to Table 9.15.4.2.A.:

⁽¹⁾See Article 9.15.4.3.

Table 9.15.4.2.B. Reinforced Concrete Block Foundation Walls Forming Part of Sentence 9.15.4.2.(4)

Column 1	Colun 2	Column 3	Column 4	Column 5	Column 6
Minimum Wall Thickness, mm	Maximum Height of Finished Ground above Basement Floor or Crawl Space Ground Cover, m	Foundation Wall Laterally Unsupported at Top ⁽¹⁾		Foundation Wall Laterally Supported at Top ⁽¹⁾
		Continuous Vertical Reinforcement		Continuous Vertical Reinforcement
		Minimum Bar Size	Maximum Bar Spacing, m	Minimum Bar Size	Maximum Bar Spacing, m
190	1.0	25M	1.2	⁽²⁾	⁽²⁾
	1.2	25M	1.2	⁽²⁾	⁽²⁾
	1.4	25M	1.2	15M	1.2
	1.6	25M	0.8	15M	1.2
	1.8	25M	0.6	20M	1.2
	2.0	25M	0.4	20M	1.2
	2.2	⁽³⁾	⁽³⁾	25M	1.2
	2.4	⁽³⁾	⁽³⁾	25M	1.2
240	1.4	25M	1.0	⁽²⁾	⁽²⁾
	1.6	25M	1.0	⁽²⁾	⁽²⁾
	1.8	25M	0.8	⁽²⁾	⁽²⁾
	2.0	25M	0.8	20M	1.8
	2.2	25M	0.8	25M	1.8
	2.4	25M	0.6	25M	1.8

Notes to Table 9.15.4.2.B.:

⁽¹⁾See Article 9.15.4.3.

⁽²⁾No reinforcement required.

⁽³⁾Design to Part 4.

9.15.4.3. — Foundation Walls Considered to be Laterally Supported at the Top

(1) Sentences (2) to (4) apply to lateral support for walls described in Sentence 9.15.4.2.(1)v1.

(2) Foundation walls shall be considered to be laterally supported at the top if,

(a) such walls support solid masonry superstructure,

(b) the floor joists are embedded in the top of the foundation walls, or

(c) the floor system is anchored to the top of the foundation walls with anchor bolts, in which case the joists may run either parallel or perpendicular to the foundation walls.

(3) Unless the wall around an opening is reinforced to withstand earth pressure, the portion of the foundation wall beneath an opening shall be considered laterally unsupported, if,

(a) the opening is more than 1.2 m wide, or

(b) the total width of the openings in the foundation wall constitutes more than 25% of the length of the wall.

(4) For the purposes of Sentence (3), the combined width of the openings shall be considered as a single opening if the average width is greater than the width of solid wall between them.

(5) Flat insulating concrete form foundation walls shall be considered to be laterally supported at the top if the floor joists are installed according to Article 9.20.17.5.v1

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9.15.4.4. — Foundation Walls Considered to be Laterally Supported at the Bottom

(1) Flat insulating concrete form foundation walls shall be considered to be laterally supported at the bottom where the foundation wall,

(a) supports backfill not more than 1.2 m in height,

(b) is supported at the footing by a shear key and is supported at the top by the ground floor framing, or

(c) is dowelled to the footing with not less than 15M bars spaced not more than 1.2 m o.c.

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9.15.4.5. — Reinforcement for Flat Insulating Concrete Form Foundation Walls

(1) Horizontal reinforcement in flat insulating concrete form foundation walls shall,

(a) consist of,

(i) one 10M bar placed not more than 300 mm from the top of the wall, and

(ii) 10M bars spaced not more than 600 mm o.c., and

(b) be located,

(i) in the inside half of the wall section, and

(ii) with a minimum cover of 30 mm from the inside face of the concrete.

(2) Vertical wall reinforcement in flat insulating concrete form foundation walls shall,

(a) conform to,

(i) Table 9.15.4.5.A. for 140 mm walls,

(ii) Table 9.15.4.5.B. for 190 mm walls, and

(iii) Table 9.15.4.5.C. for 240 mm walls,

(b) be located in the inside half of the wall section with a minimum cover of 30 mm from the inside face of the concrete wall, and

(c) where interrupted by wall openings, be placed not more than 600 mm from each side of the openings.

(3) Cold joints in flat insulating concrete form foundation walls shall be reinforced with at least one 15M bar spaced not more than 600 mm o.c. and embedded not less than 300 mm on both sides of the joint.

(4) Reinforcing around openings in flat insulating concrete form foundation walls shall comply with Articles 9.20.17.3.v1 v2 or 9.20.17.4.

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Table 9.15.4.5.A. Vertical Reinforcement for 140 mm Flat Insulating Concrete Form Foundation Walls Forming Part of Sentence 9.15.4.5.(2)


Column 1	Column 2	Column 3	Column 4
Maximum Height of Finished Ground Above Finished Basement Floor, m	Maximum Vertical Reinforcement
	Maximum Unsupported Basement Wall Height
	2.44 m	2.75 m	3.00 m
1.35	10M at 400 mm o.c.	10M at 400 mm o.c.	10M at 400 mm o.c.
1.60	10M at 400 mm o.c.	10M at 380 mm o.c.	10M at 380 mm o.c.
2.00	10M at 380 mm o.c.	10M at 380 mm o.c.	10M at 380 mm o.c.
2.20	10M at 250 mm o.c.	10M at 250 mm o.c.	10M at 250 mm o.c.
2.35	n/a	10M at 250 mm o.c.	10M at 250 mm o.c.
2.60	n/a	10M at 250 mm o.c.	10M at 250 mm o.c.
3.00	n/a	n/a	15M at 250 mm o.c.

Table 9.15.4.5.B. Vertical Reinforcement for 190 mm Flat Insulating Concrete Form Foundation Walls Forming Part of Sentence 9.15.4.5.(2)


Column 1	Column 2	Column 3	Column 4
Maximum Height of Finished Ground Above Finished Basement Floor, m	Maximum Vertical Reinforcement
	Maximum Unsupported Basement Wall Height
	2.44 m	2.75 m	3.00 m
2.20	none required	10M at 400 mm o.c.	10M at 400 mm o.c.
2.35	n/a	10M at 300 mm o.c.	10M at 300 mm o.c.
2.60	n/a	10M at 300 mm o.c.	15M at 400 mm o.c.
3.00	n/a	n/a	15M at 400 mm o.c.

Table 9.15.4.5.C. Vertical Reinforcement for 240 mm Flat Insulating Concrete Form Foundation Walls Forming Part of Sentence 9.15.4.5.(2)


Column 1	Column 2	Column 3	Column 4
Maximum Height of Finished Ground Above Finished Basement Floor, m	Maximum Vertical Reinforcement
	Maximum Unsupported Basement Wall Height
	2.44 m	2.75 m	3.00 m
2.20	none required	none required	none required
2.60	n/a	15M at 400 mm o.c.	15M at 400 mm o.c.
3.00	n/a	n/a	15M at 400 mm o.c.

9.15.4.6. — Extension above Ground Level

(1) Exterior foundation walls shall extend not less than 150 mm above finished ground level.

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9.15.4.7. — Reduction in Thickness

(1) Where the top of a foundation wall is reduced in thickness to permit the installation of floor joists, the reduced section shall be not more than 350 mm high and not less than 90 mm thick.

(2) Where the top of a foundation wall is reduced in thickness to permit the installation of a masonry exterior facing, the reduced section shall be,

(a) not less than 90 mm thick, and

(b) tied to the facing material with metal ties conforming to Sentence 9.20.9.4.(3) spaced not more than,

(i) 200 mm o.c. vertically, and

(ii) 900 mm o.c. horizontally.

(3) The space between wall and facing described in Sentence (2) shall be filled with mortar.

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9.15.4.8. — Corbelling

(1) Corbelling of masonry foundation walls supporting cavity walls shall conform to Article 9.20.12.2.

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9.15.4.9. — Crack Control Joints

(1) Crack control joints shall be provided in foundation walls more than 25 m long at intervals of not more than 15 m.

(2) Joints required in Sentence (1) shall be designed to resist moisture penetration and shall be keyed to prevent relative displacement of the wall portions adjacent to the joint.

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9.15.4.10. — Interior Masonry Walls

(1) Interior masonry foundation walls not subject to lateral earth pressure shall conform to Section 9.20.

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9.15.4.

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