Does framing lumber need to be grade stamped in Ontario?
Yes. Structural framing lumber must be identified by a grade stamp showing it was graded under NLGA rules by an accredited agency. Ungraded or homemade sawmill lumber generally cannot be used for structure.
Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.
The Part 9 span tables assume specific species groups (like S-P-F) and grades (No. 1/No. 2), so the grade stamp is what connects your joists and rafters to the allowed spans. Inspectors routinely fail framing built with unstamped lumber, including rough-cut boards from local sawmills, unless an engineer certifies the members. When buying, check the stamp for species, grade, agency, and moisture designation. Keep stamps visible where practical until framing inspection is complete.
Every structural stick of lumber needs a stamp proving its grade and species. That stamp is what lets your builder use the code's span tables. Bargain unstamped lumber from a sawmill usually can't be used for framing.
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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.