Things You'll Need
When framing a new roof for a home or addition, the rafter tails must be cut before the roof sheathing and fascia boards can be installed. There's a time-tested procedure used by framing contractors and carpenters for cutting the rafter tails accurately and ensuring a straight fascia line. It's simple enough for a do-it-yourselfer to use.
Measure the desired overhang length of the rafter tails with a tape measure and mark the top edge of both end rafters at this dimension, using a pencil.
Snap a continuous chalk line on the top of the rafter tails between the two marks on the end rafters.
Mark the cut line on the side face of each rafter tail. There are two typical fascia angles in home construction: plumb or vertical, with the fascia installed vertically parallel with the exterior wall surface, and square, with the fascia installed perpendicular to the roof pitch. Aligning with the overhang chalk line, use a hand square to mark the cut line for a square fascia application or use a level to mark the plumb cut for the rafter tails.
Cut each rafter tail at the cut lines, using a circular saw. Once cut, the rafter tails are ready for installation of the fascia boards and roof sheathing.
The rafter tails can be cut standing on the roof above or from a scaffolding below, but make certain you are working from a stable platform to ensure accurate cuts and safety.