The Ontario Building Code | Thickness and Width
188.8.131.52. Thickness and Width
(1) Drop, rustic, novelty, lapped board and vertical wood siding shall be not less than 14.3 mm thick and not more than 286 mm wide.
(2) Bevel siding shall be,
(a) not less than 5 mm thick at the top, and
(b) not less than,
(i) 12 mm thick at the butt for sidings 184 mm or less in width, and
(ii) 14.3 mm thick at the butt for sidings wider than 184 mm.
(3) Bevel siding shall be not more than 286 mm wide.