Birdsmouth Cut Calculator
Find the seat cut length and heel cut depth so a rafter sits flush on the wall top plate.
LIVE CALCULATION
Seat Cut Length
0
in
By Heel Depth · roof 6/12
Cut Summary
Rafter Cut
Cost Estimate
Estimated Total-
Calculation Assumptions
Rafter / Style-
Roof Pitch-
Heel & Seat Cuts-
Cut Math-
Notch Rule-
Pricing BasisNot specified
The heel cut (vertical) and seat cut (horizontal) form the birdsmouth notch that hooks a rafter over the wall top plate. As a common rule, the heel cut should not exceed about 1/3 of the rafter depth, and the seat cut should not be longer than the width of the top plate it rests on.
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