The Ontario Building Code | OSB, Waferboard and Plywood Marking
(1) OSB, waferboard and plywood used for roof sheathing, wall sheathing and subflooring="http://thehandyforce.com/flooring/" title ="Handyman flooring install Toronto">flooring shall be legibly identified on the face of the material indicating,
(a) the manufacturer of the material,
(b) the standard to which it is produced, and
(c) that the material is of an exterior type.