Code Library › Volume 1 › Section 9.21 — Masonry and Concrete Chimneys
PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code

9.21.4.4.Height of Chimney Flues

(1) A chimney flue shall extend not less than (a) 900 mm above the highest point at which the chimney comes in contact with the roof, and (b) 600 mm above the highest roof surface or structure within 3 m of the chimney. (See Note A-9.21.4.4.(1))
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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.