How To Birdsmouth A Roof Rafter

The ridge cut also called the plumb cut at the top of the rafter the birdsmouth cut which itself comprises 2 different cuts where the rafter meets the building s wall and the tail cut at the base of the rafter.

How to birdsmouth a roof rafter.

Measure or calculate the height of the roof from the top of the wall to the top of the ridge plate and multiply that number by itself. Multiply your pitch by 24 to determine the rise per foot of run. Among the most important individual components is the birdsmouth joint. Calculate the pitch of your roof.

This notch allows the beam to rest flush onto the top plate. The roof rafters provide integral structural support to the roof. From the marked point draw a line at the same angle as the pitch of the rafter up and make a mark at 1 1 2 inches. How do i know where to cut the bird s mouth in a rafter.

Also known as a bird s mouth joint or sometimes a bird s beak notch this type of cut is typically used to securely connect a rafter to the top of a supporting wall with the help of a wall plate. Pitch rise run x 2. Due to the width. Measure along the top of the rafter the distance that you calculated in the previous step.

A birdsmouth cut involves taking a notch shaped like a bird s mouth out of each rafter where it meets the top plate. When it comes to laying out a rafter it s essential to understand the basic building blocks of framing. This 90 degree angle forms the bird s mouth. When you cut the rafters you ll need to make 3 separate cuts.

So to summarise the full process is as follows. The result of this equation represents the. Possibly the most satisfiying part of the roof yet. In my photo above the green rafter line length is from the plumb cut face or ridge board face to the plumb cut face of the bird s mouth notch.

Rise is the vertical distance from the top plate of. How to cut bird s mouths in rafters step 1. Calculate pitch of roof use roof pitch to cut ridge cut use ridge cut as point of reference to form birdsmouth make tail cut. From that line across the rafter draw a perpendicular line at the 1 1 2 inch mark out towards inside part of the rafter.