The Ontario Building Code | Required Resistance to Heat Transfer
5.3.1.1. Required Resistance to Heat Transfer
(1) Except as provided in Sentence (2), where a buildingcomponent or assembly will be subjected to an intended temperature differential, the component or assembly shall include materials to resist heat transfer or means to dissipate transferred heat in accordance with this Subsection.
(2) The installation of materials to resist heat transfer in accordance with this Subsection is not required where it can be shown that uncontrolled heat transfer will not adversely affect any of,
(a) the health or safety of building users,
(b) the intended use of the building, or
(c) the operation of building services.
In Plain Language
Except in specific cases, where a building component or assembly is subjected to a temperature differential, it must be designed to provide the required resistance to heat transfer set out in this Subsection.
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.