The Ontario Building Code | Wood Frame Roof Systems
220.127.116.11. wood Frame Roof Systems
(a) spaced not more than 2.4 m apart,
(b) embedded not less that 90 mm into the masonry, and
(c) fastened to a rafter plate of not less than 38 mm thick lumber.
(2) The roof system described in Sentence (1) is permitted to be anchored by nailing the wall furring strips to the side of the rafter plate.