The Ontario Building Code | Shaping of Rafters
9.23.13.5. Shaping of Rafters
(1) Rafters shall be shaped at supports to provide even bearing surfaces and supported directly above the exterior walls.
In Plain Language
Rafters may need shaping (such as a birdsmouth cut) as set out in this article, allowing them to seat properly on the supporting wall while maintaining structural strength.
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.