The Ontario Building Code | Size of 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 38 mm thick, and
(b) not less than the required width of the wall studs.
(2) In non-loadbearing walls and in loadbearingwalls where the studs are located directly over framing members, the bottom wall plate may be 19 mm thick.
In Plain Language
Wall plates must meet the size requirements set out in this article, covering both the top and bottom horizontal members that studs connect to.
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.