The Ontario Building Code | Subflooring Required
9.23.14.1. Subflooring Required
(1) Subflooring shall be provided beneath finish flooring where the finish flooring does not have adequate strength to support the design loads.
In Plain Language
Subflooring is required over floor joists, as set out in this article, providing a structural platform beneath the finished floor covering.
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.