The Ontario Building Code | Masonry and Concrete
9.22.1.2. masonry and Concrete
(1) Except as otherwise stated in this Section, unit masonry shall conform to Section 9.20. and concrete to Section 9.3.
(2) masonry above openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings shall be supported by steel lintels conforming to Sentence 9.20.5.2.(2), reinforced concrete or a masonry arch.
In Plain Language
Masonry and concrete used in fireplace construction must meet the requirements set out in this article.
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.