Usually, roof frames are made by professional manufacturers with expertise in frame construction. The skill is a very special one and takes years of training and experience gained in the field of roof framing to create the best examples of this. Sadly, the craft is dying out. It's being replaced by the now popular truss roofs. Conventional framing which has been around for several centuries is now getting overshadowed by modern developments where you get pre-fab roofs.
But, where you need a lot of customization in framing still rules the roost. These techniques are useful when creating extra space by adding garages, sheds, or similar structures to an existing structure. The costs of delivery are lower and they can work with space constraints. These are also much lighter than truss roofs. To learn more about calculating the length of rafter needed for roof framing just follow the steps outlined below.
Designing Roof Framing Rafters
A common rafter in framing has several parts called the tail cut, birdsmouth cut, plumb cut, wall stud, ridge board, ceiling joist, and many more. Measuring roof rafters have to start with calculating the pitch, length of rafter, spacing between rafters, and lumber size.
The overall width of your building is determined by measuring the span of the framing rafter. This is the point where the rafters will sit. On the other hand, the run is half of this span measured earlier. This horizontal distance is what your rafter will run to meet the one from the opposite side.
An important cut in the rafters called the birdsmouth cut helps the rafters to rest on the outside wall of the buildings. Unless the cut is at least 4 inches the rafter can not achieve full bearing. This can be achieved by sliding the framing square along the rafter until you get the desired cut depth on the rafter that you have marked out earlier.