The Ontario Building Code | Cornices, Sills and Trim
9.20.11.5. Cornices, Sills and Trim
(1) Cornices, sills or other trim of masonry material that project beyond the wall face shall have not less than 65% of their mass, but not less than 90 mm, within the wall or shall be adequately anchored to the wall with corrosion-resistant anchors.
In Plain Language
For projecting masonry trim like cornices or sills, this clause requires either that at least 65% of the piece's mass (and not less than 90 mm) stays embedded within the wall, or that the piece is securely anchored to the wall with corrosion-resistant anchors.
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.