The Ontario Building Code | Installation of Layers
9.26.11.7. installation of Layers
(1) In hot process applications, each layer of bitumen-saturated felt shall be laid while the bitumen is hot, with each layer overlapping the previous one.
(2) The full width under each lap referred to in Sentence (1) shall be coated with bitumen so that in no place does felt touch felt.
(3) Felt shall be laid free of wrinkles and shall be rolled directly into the hot bitumen and broomed forward and outward from the centre to ensure complete adhesion.
In Plain Language
Layers of built-up roofing must be installed as set out in this article, ensuring each ply is properly bonded and overlapped with the ones before and after it.
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.