9.23.16.4 — Lumber Sheathing

(1) Except as provided in Sentence (2), each exterior wall in each storey shall be braced with at least one diagonal brace conforming to Sentence (3). (2) Bracing is not required where the walls, (a) have an interior finish conforming to the requirements of Section 9.29., or (b) where the walls are, (i) clad with panel-type siding, (ii) diagonally sheathed with lumber, or (iii) sheathed with plywood, OSB, waferboard, gypsum or fibreboard sheathing. (3) Where bracing is required, it shall, (a) consist of not less than 19 mm by 89 mm wood members, (b) be applied to the studs at an angle of approximately 45° to the horizontal, and (c) extend the full height of the wall on each storey. (4) Bracing described in Sentence (3) shall be nailed to each stud and wall plate by at least two 63 mm nails. (5) Where loadbearing interior walls are not finished in accordance with Sentence (2), blocking or strapping shall be fastened to the studs at mid-height to prevent sideways buckling.