In Plain Language

A vapour barrier may also serve as the air barrier under the conditions set out in this article, letting a single material do double duty provided it meets both sets of performance requirements.

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.