Code Library › Volume 1 › Section 9.18 — Crawl Spaces
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.18.7.1.Crawl Spaces as Warm Air Plenums

(1) Only crawl spaces under 1-storey portions of dwelling units shall be used as warm air plenums. (2) Enclosing material in crawl spaces described in Sentence (1), including insulation, shall have a surface flame-spread rating not greater than 150. (3) Combustible ground cover used as enclosing material in Sentence (2) shall be covered with noncombustible material. (See Note A-9.18.7.1.(3) and (4)) (4) Noncombustible material described in Sentence (3) shall (a) extend not less than 300 mm beyond the projection of a register opening, and (b) have turned-up edges. (See Note A-9.18.7.1.(3) and (4))
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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.