Code Library › Volume 1 › Section 9.26 — Roofing
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.26.10.2.Underlay

(1) Where eave protection is not provided, an underlay conforming to the requirements in Article 9.26.6.1. for wood shingles shall be laid as a strip not less than 900 mm wide along the eaves. (2) A strip of material similar to that described in Sentence (1) not less than 450 mm wide shall be interlaid between each course of shakes with the bottom edge of the strip positioned above the butt line at a distance equal to double the exposure of the shakes. (3) Interlaid strips referred to in Sentence (2) shall be lapped not less than 150 mm at hips and ridges in a manner at will prevent water from reaching the roof sheathing.
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What is the minimum roof slope for asphalt shingles and other roofing materials in Ontario?Where is ice and water shield (eave protection) required on roofs in Ontario?What are the roof flashing requirements for valleys, walls and chimneys in Ontario?

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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.