Birdsmouth joints cut into roofing rafters and mounted in place on top of the wall plate.
How do i cut roof raqfters.
The pitch and span of your roof will dictate how long of a rafter you ll need use maximum span calculator to help you find your rafter size.
Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter.
One thing that i can t stress enough be sure that your measurements are rock solid before you mark or cut anything.
If is wasn t for this joint a rafter or roofing joist would only balance on top of the wall plate making fixing difficult not to mention the fact that there wouldn t be any solid connection between the roof and the supporting walls below.
The ridge end of the rafter and often the eve end will need to be cut to the angle of the roof slope.
The roof rafters provide integral structural support to the roof.
The first step in building the roof rafters is to cut one rafter board to length with the ends angled properly and then to mark and cut the birds mouth and seat on the rafter.
Hopefully after reading this guide you see how easy it is to cut rafters once you get the hang of it.
Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.
Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.
In this video you will learn all about common rafters.
When you cut the rafters you ll need to make 3 separate cuts.
How to measure or figure rafter length and mark and cut them accurately.
The ridge cut also called the plumb cut at the top of the rafter the birdsmouth cut.
Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof.
If you look at the rafter span chart you ll notice that 2x4s can be used for rafters on spans up to 11.
