The Ontario Building Code | Material Standards
9.23.14.2. Material Standards
(1) Except as provided in Sentence (2), wood-based panels for subfloors shall conform to,
(a) CSA O121, "Douglas Fir Plywood",
(b) CSA O151, "Canadian Softwood Plywood",
(c) CSA O153-M, "Poplar Plywood",
(d) CSA O325, "Construction Sheathing", or
(e) CSA O437.0, "OSB and waferboard".
(2) Particleboard subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring may be used only where a building is constructed in a factory so that the subfloor will not be exposed to the weather.
(3) Subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring described in Sentence (2) shall conform to grade D-2 or D-3 in ANSI A208.1, "Particleboard".
(4) Subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring described in Sentence (2) shall have its upper surface and all edges treated to restrict water absorption where the subfloor is used in bathrooms, kitchens, laundry rooms or other areas subject to periodic wetting.
In Plain Language
Subflooring materials must conform to the standards referenced in this article, ensuring the panel or lumber product meets recognized structural performance criteria.
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.