The Ontario Building Code | Laying Temperature of Mortar and Masonry
9.20.14.1. Laying temperature of Mortar and masonry
(1) mortar and masonry shall be maintained at a temperature not below 5°C during installation and for not less than 48 h after installation.
(2) No frozen material shall be used in the mortar mix.
In Plain Language
Mortar and masonry must be laid within the temperature range set out in this article, since extreme cold or heat can prevent mortar from curing and bonding properly.
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.