03.Birdsmouth
What Is a Birdsmouth Cut in Roof Framing—and Why Does It Matter?
A birdsmouth is a precise triangular notch cut into the bottom of a rafter, allowing it to sit securely on a wall’s top plate during roof construction. It consists of two key cuts: the seat cut, which rests flat on the wall, and the heel cut, which fits tightly against the wall’s exterior. This joint ensures structural stability and proper load distribution. A critical rule when cutting a birdsmouth is to never remove more than one-third of the rafter’s depth, preserving the integrity and strength of the overall roofing system
