The Ontario Building Code | Support of Floor Joists
9.15.5.1. support of floor joists
(1) Except as permitted in Sentence (2), foundation walls of hollow unit masonry supporting floor joists shall be,
(a) capped with not less than 50 mm of solid masonry or concrete, or
(b) have the top course filled with mortar or concrete.
(2) Capping required in Sentence (1) is permitted to be omitted,
(a) in localities where termites are not known to occur,
(b) when the joists are supported on a wood plate not less than 38 mm by 89 mm, and
(c) when the siding overlaps the foundation wall not less than 12 mm.
In Plain Language
Floor joists must be supported by the foundation as set out in this article, ensuring proper bearing and connection between the floor structure and the foundation below.
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.