The Ontario Building Code | Capping of Hollow Masonry Walls
9.20.8.1. Capping of Hollow masonry Walls
(1) Except as permitted in Sentence (2), loadbearing walls of hollow masonry units supporting roof or floor framing members shall be capped with not less than 50 mm of solid masonry or have the top course filled with concrete.
(2) Capping required in Sentence (1) may be omitted where the roof framing is supported on a wood plate not less than 38 mm by 89 mm.
In Plain Language
Hollow masonry walls need capping at their top as set out in this article, sealing the hollow cores against water infiltration.
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.