The Ontario Building Code | Thickness
9.27.9.2. Thickness
(1) Type 1 or 2 hardboard cladding shall be not less than,
(a) 6.0 mm thick when applied over sheathing that provides continuous support, and
(b) 7.5 mm thick when applied to furring or framing members not more than 406 mm o.c.
(2) Type 5 hardboard cladding shall be not less than 9.0 mm thick when applied over sheathing that provides continuous support or over furring or framing members spaced not more than 406 mm o.c.
(3) Where hardboard cladding is grooved, the grooves shall not extend more than 1.5 mm into the minimum required thickness.
In Plain Language
This cladding material must meet the minimum thickness set out in this article.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.