The Ontario Building Code | Direction of Installation
9.23.14.4. Direction of installation
(1) Plywood subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring shall be installed with the surface grain at right angles to the joists and with joints parallel to floor joists staggered.
(2) OSB subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring conforming to CSA O325, "Construction Sheathing", or to O-1 and O-2 grades in CSA O437.0, "OSB and waferboard", and waferboard subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring conforming to R-1 grade in CSA O437.0 shall be installed so that the direction of face orientation is at right angles to the joists and the joints parallel to the floor joists are staggered.
In Plain Language
Subfloor panels must be installed in a specific direction relative to the joists, as set out in this article, maximizing their structural performance.
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.