(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.
Article 184.108.40.206. Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only.
Source : Canada Mortgage and Housing Corporation (CMHC)
Note : A cant strip is a strip of material of triangular section placed at the intersection of a roof deck with a higher wall or other vertical surface.” Cant strips have been, and continue to be widely used as a component of built-up roofing because they are thin, lightweight, low in cost and easy to install. Cant strips enhance the strength and longevity of built up roofs.