How To Build Roof Rafters
Properly constructed roof rafters are essential to a structurally sound roof as they are the main support for the roof. They are a main part of the roof framing, going from the ridgebeam to the walls and supporting the sheathing, which goes on right before the shingles. This is the basic structure of the house and goes up before anything else such as rigid insulation. Because each style of roof has a different height and slope, the roof frame and therefore the rafters will be different for different roof styles, including gambrel, gable, and shed roofs. Building a roof frame correctly is vital and the rafters may determine whether the roof stands or falls. This article will briefly discuss how to build roof rafters so that your roof is supported in the right way.
Preparation for Building Roof Rafters
Before you start the actual building, you'll need a few things. Make sure you have a long tape measure, a saw, a framing square, wood 2 x 4s or 6s, two saw horses, a pencil, gloves, and goggles for safety. An essential part of how to build roof rafters is figuring out how long the rafters need to be, which will depend again on the roof style. The roof pitch is the determining factor in rafter length. The roof pitch is the slope of the roof. You can figure this out using the Pythagorean theorem.
Once you know how long the rafters should be for your roof, you can start cutting. First, set your 2 x 4 on the saw horses. Using your framing square, measure where you will cut your pitch or plumb angle, which must be flush to lay flat against the ridgebeam, and then mark where the heel cut will be at the bottom of the rafter. Then you need to mark where the bird's mouth will be, or a notch that will sit on the edge of the building. Double check your measurements and cut that first rafter flush. Once you have done that and you're positive it's accurate, lay that rafter on top of the other 2 x 4s and use a pencil to mark where to make your cuts. This ensures accurate and identical rafters for the entire roof structure. Once you've finished this part, you can move to the next step in how to build roof rafters.
The next step in how to build roof rafters is laying out where the rafters will go on the roof. You can't just go up there and start nailing, you need a pattern to follow. First, mark the wall plates 1 1/2 inches from the end and then make a mark every 16 inches on center until you've gotten to 1 1/2 inches from the opposite end. Do the same to the ridgebeam, making a mark 1 1/2 inches from the end and then marking it every 16 inches on center. Then you can start putting the rafters on the roof.
Make sure you have some 16 penny nails. Nail the first rafter to the first mark on the ridgebeam with three nails. Then nail another rafter to the opposite end of the ridgbeam using four nails at an angle. Then nail the bottoms of the rafters at the bird's mouth onto the wall plate with two nails. Follow this pattern for the rest of the rafters, following closely the marks you made previously. Take a step back every so often as well to make sure everything looks plumb and level. And that is how to build roof rafters.
