The Ontario Building Code | Firebrick Liners
(1) fireplace liners shall be not less than,
(a) 50 mm thick for the sides and back, and
(b) 25 mm thick for the floor.
(2) Firebrick liners shall be laid with high temperature cement mortar conforming to CAN/cgsb-10.3, "Air Setting Refractory mortar".
(3) Joints between a firebrick liner and the adjacent back-up masonry shall be offset.
In Plain Language
Firebrick liners for a fireplace have specific requirements set out in this article, addressing this common, heat-resistant lining material.
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.