The Ontario Building Code | Cant Strips
9.26.11.10. Cant Strips
(1) Except as permitted in Sentence (4), a cant strip shall be provided at the edges of roofs.
(2) No fewer than two plies of the roofing membrane shall be carried over the top of the cant strip.
(3) Flashing shall extend over the top of the cant strip and be shaped to form a drip.
(4) The cant strip required in Sentence (1) may be omitted where a gravel stop is provided at the edge of roofs.
(5) The roofing membranes shall be carried over the edge of the roof before the gravel stop referred to in Sentence (4) is fastened and two plies of roofing membrane mopped to the top surface of the gravel stop before the flood coat is applied.
(6) The gravel stop referred to in Sentence (4) shall extend over the edge of the roof to form a drip or shall be flashed so that the flashing extends over the edge to form a drip.
9.26.12. Selvage Roofing
In Plain Language
Cant strips, angled pieces used to ease the transition between a flat roof surface and a vertical wall, are required as set out in this article, since built-up roofing can't easily bend around a sharp 90-degree corner.
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.