For this example a section of roof is 20 feet wide.
How to notch out a 2x4 for a roof.
Birdsmouth joint how to cut a birdsmouth and how to cut and install roofing rafters and joists.
Measure each section of the roof from side to side parallel to the line of the fascia board.
If you re framing a gable roof on a new house or building a shed or even a doghouse with a gable roof you ll need to cut a number of roof rafters.
For the rafter to fit correctly you need to cut the bird s mouth exactly where the rafter will meet the wall.
Measure out the span of your arch on a sheet of your plywood and cut a piece of string to the same length represented in the images as the line which connects a to b.
Layout your sheet of plywood on sawhorses.
Access the roof using an extension ladder.
You are going to cut out triangles that will cover the apex of each set of rafters.
The rule of thumb is that the gusset should be twice the width of the wood you use for your rafters.
Each side of the gusset will be 8 long but only 8 tall.
Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter.
Find the center point of your first measurement on the plywood and draw a line at a 90 degree angle from that center point until you reach the desired height of your arch.
In this diy guide you will learn how to install a roofing joist or rafter that includes how to work out the pitch of a roof cut a ridge or plumb cut at the correct angle work out the correct length of joist you need and the exact location for a birds mouth joint how to correctly cut a birds.
The roof rafters provide integral structural support to the roof.