Roof Rafter Birdsmouth Cut

Birdsmouth joints cut into roofing rafters and mounted in place on top of the wall plate.

Roof rafter birdsmouth cut.

Half building width minus 1 2 ridge thickness. First off the plumb cuts are better left until all of the rafters are in place on the roof using a chalk line to get the plumb cuts in a dead straight line making the fascia board fit nicely. For the rafter to fit correctly you need to cut the bird s mouth exactly where the rafter will meet the wall. The actual indentation or cut is known as the birdsmouth while the birdsmouth plumb is the depth of the cut out.

Because a roof requires many rafters to frame it speeds things along if you use the first rafter as a pattern or template for the other rafters. Please consult a professional before making any cuts i am not a professional framer or roofer nor do i claim to be. Creating a birdsmouth cut is the classic way. Here the birdsmouth plumb is 76 37 inches.

When you cut the rafters you ll need to make 3 separate cuts. This trick worked for me. Allow for ridge thickness when determining rafter run to outer wall. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through.

The drawings and the size of the rafters are generated in real time. The length of rafters length overhang the angle of the saw cut the distance to drinking. Online calculator produces an accurate calculation of the rafters online calculates the sizes of rafters for the roof. See rafter run to outer wall calculator below.

Second even if the plumb cuts at the rafter s lower end have already been made small variations in rafter length and effects of bowed or arched rafters will throw off your birds mouth location. Once you ve cut the top end of the first rafter you can calculate the position of the bird s mouth based on the height and width of the roof then use that rafter as a pattern to cut the others. Use it to make the proper measurements marks and cuts on each 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.

Birdsmouth plumb if you study the diagram carefully you will see that there is an indentation in the roof rafter where it meets the exterior wall of the building.