How to Fix Rafter Tails

Install scaffolding underneath the roof edge or place a ladder under each end rafter for one section of the roof. Make sure each rafter is equally spaced and tightly nailed to the building.

Extend a string from one end to the other. The string needs to be pulled tight in order to check the location and length of each individual rafter. A string that lightly touches the plumb cut of each rafter indicates a job well done and that you can continue. Any rafter that pushes the string out away from the house is too long and needs to be shortened.

Look up the width of the fascia header. This is the board that is attached to the ends of the rafters. Often, it is the same width as the rafter. However, the plumb cut will be longer than the width of its rafter, so one more cut on the end of the rafter is still necessary. This cut is made at a right angle to the plumb cut, which, if done correctly, is a vertical line. You can check the plumb cut with the 2-foot level, if you like. For this discussion, a fascia header width of 5 1/2 inches will be used, which is a common dimension.

Measure down 5 1/2 inches from the top of the plumb cut on the first and last rafter of one side of the building. Make a mark on each end with the pencil.

Extend a chalk line between the two marks.

Pull the line taut and snap a line that leaves a mark on every plumb cut. This step may require a third person in the middle to snap the line.

Place the lip of the speed square on the plumb cut and line up the pivot point with the chalk line. Make sure the lip is pulled tight against the plumb cut and then extend a line back across the face of the rafter, using the bottom edge of the speed square as a guide. Do this for each rafter.

Place the hand saw along the pencil line and cut off the bottom tip of the rafter. Be certain to keep the saw blade perpendicular to the face of the rafter for the entire cut. Do this for each rafter.