Code Library › Volume 1 › Section 9.8 — Stairs, Ramps, Handrails and Guards
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.8.9.5.Treads

(1) Stair treads of lumber, plywood or O-2 grade OSB within dwelling units shall be not less than 25 mm actual thickness, except that, if open risers are used and the distance between stringers exceeds 750 mm, the treads shall be not less than 38 mm actual thickness. (2) Stair treads of plywood or OSB, that are not continuously supported by the riser shall have their face grain or direction of face orientation at right angles to the stringers.
← Previous9.8.9.4. Wooden Stair StringersNext →9.8.9.6. Finish for Treads, Landings and Ramps (See Note

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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.