The Ontario Building Code | Size of Wall Plates
18.104.22.168. Size of wall Plates
(1) Except as provided in Sentence (2), wall plates shall be,
(a) not less than 38 mm thick, and
(2) In non-loadbearing walls and in wallehandyforce.com/renovations/" title ="East York General Contractor">loadbearingwalls where the studs are located directly over framing members, the bottom wall plate may be 19 mm thick.