The Ontario Building Code | Face Sealed Cladding
220.127.116.11. Face Sealed Cladding
(1) Sheathing membrane is permitted to be omitted beneath cladding when the joints in the cladding are formed to effectively prevent the passage of wind and rain in conformance with Sentence (2) or (3), as applicable.
(a) all edges are directly supported by framing,
(b) the vertical joints between adjacent sheets are sealed and,
(i) covered with battens,
(ii) shiplapped, or
(iii) otherwise matched to provide weathertight joints, and
(c) the horizontal joints between adjacent sheets are sealed and,
(i) shiplapped, or
(ii) otherwise matched to provide weathertight joints.
(3) Metal siding consisting of sheets of metal is considered to meet the requirements of Sentence (1) where the joints between sheets are of the locked-seam type.