Notice: This site currently shows the 2012/2017 edition of the Ontario Building Code. The current legally effective code is the 2024 edition (O.Reg. 163/24), in effect since January 1, 2025. Confirm current requirements at ontario.ca.
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The Ontario Building Code | Inclined Chimney Flues

9.21.2.3. Inclined Chimney Flues

(1) Chimney flues shall not be inclined more than 45° to the vertical.

In Plain Language

Inclined chimney flues, which don't run straight up, must meet the requirements set out in this article, since an angled flue affects draft and safe venting differently than a vertical one.

This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.