In Plain Language

This clause requires wide-selvage asphalt roofing to provide double coverage across the entire roof surface, meaning each course overlaps enough that two layers of material cover every point on the roof, not just a single layer with narrow overlaps.

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.