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

9.21.3.2.Joints in Chimney Liners

(1) Joints of chimney liners shall be sealed to provide a barrier to the passage of flue gases and condensate into the cavity between the liner and the surrounding masonry. (2) Joints of clay, concrete or firebrick chimney liners shall be struck flush to provide a straight, smooth, aligned chimney flue.
← Previous9.21.3.1. Lining MaterialsNext →9.21.3.3. Clay Liners

Common questions about this part of the code

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?

Understand this provision in seconds

BUILDAiD Assist explains any article of the building code in plain English — with exact citations, exceptions and related requirements.

Try BUILDAiD Beta

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.