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

9.21.5.2.Sealing of Spaces

(1) All spaces between masonry or concrete chimneys and combustible material shall be sealed top or bottom with noncombustible material.
← Previous9.21.5.1. Clearance from Combustible MaterialsNext →9.21.5.3. Support of Joists or Beams

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How high does a chimney have to extend above the roof in Ontario?What are the flue lining requirements for masonry chimneys in Ontario?What clearance does a masonry chimney need from combustible materials 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.