The Ontario Building Code | Thickness

9.27.8.2. Thickness

(1) Plywood cladding shall be not less than 6 mm thick when applied directly to sheathing.

(2) When applied directly to framing or over furring strips, plywood cladding thickness shall conform to Table 9.27.8.2.

Table 9.27.8.2.
Minimum Plywood Cladding Thickness

Forming Part of Sentence 9.27.8.2.(2)

Item	Column 1 Spacing of supports, mm	Column 2 Minimum Thickness, mm, where Face Grain Parallel to supports	Column 3 Minimum Thickness, mm, where Face Grain at Right Angles to supports
1.	406	8	6
2.	610	11	8

(3) The thickness of grooved or textured plywood shall be measured at the point of least thickness.