The Ontario Building Code | Protection of Cladding from Moisture
9.27.2.4. Protection of Cladding from moisture
(1) A clearance of not less than 200 mm shall be provided between finished ground and cladding that is adversely affected by moisture, such as untreated wood, plywood, OSB, waferboard and hardboard.
(2) A clearance of not less than 50 mm shall be provided between a roof surface and cladding that is adversely affected by moisture, such as untreated wood, plywood, OSB, waferboard and hardboard.
9.27.3. Second Plane of Protection
In Plain Language
Cladding must be protected from moisture, as set out in this article, since even weather-resistant cladding materials can be damaged by trapped or prolonged moisture exposure.
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.