The Ontario Building Code | Minimum Thickness
22.214.171.124. Minimum Thickness
(2) Thickness listed in Table 126.96.36.199. shall permit a manufacturing tolerance of -0.4 mm.
(3) No minimum thickness is required where O-2 grade OSB is applied over continuous backing.
(4) OSB conforming to O-1 grade, waferboard conforming to R-1 grade and particleboard shall be,
(a) not less than 6.35 mm thick on supports not more than 406 mm o.c.,
(b) not less than 9.5 mm thick on supports not more than 610 mm o.c., and
(5) OSB conforming to CSA O325, "Construction Sheathing", shall meet the minimum panel mark of,
(a) W16, on supports not more than 406 mm o.c.,
(b) W24, on supports not more than 610 mm o.c., and