The Ontario Building Code | Foundation Walls Considered to be Laterally Supported at the Top
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).
(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="http://thehandyforce.com/windows/" title ="Window installer in Toronto">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="http://thehandyforce.com/windows/" title ="Window installer in Toronto">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.
In Plain Language
A foundation wall is considered laterally supported at the top under the specific conditions set out in this article, typically where the floor structure above braces the wall.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.