How to Cut a Scissor Truss

Measure the top truss cord on the gable truss, and carefully mark the point at which the cord must be cut to frame the fascia board. Depending on the architecture of the building's exterior, the fascia board is typically installed 12 to 24 inches away from the exterior wall of the home.

Drive an 8D nail vertically into the top cord at the center of your mark. Repeat the process on the truss at the other end of the roof line. Use the exterior wall or the peak of the truss as your reference point, and mark a point on the trusses on each end of the roof line.

Drive an 8D nail into this second mark, and then stretch a chalk line between the two nails. Pull the chalk line taut, then snap a line along the top edge of the truss's top cord. This line will be perfectly straight and lay out the point to cut each truss to create the fascia framing.

Draw a vertical line downward along the side of the truss cord, starting at the line you marked along the top edge of the cord. Use a framing square and pocket level, or an adjustable pocket bevel, to draw a vertical line on each rafter cord.

Cut the end of the top truss cord, sometimes called the rafter tail, off the end of the truss. When the trusses are installed, they are positioned to create a perfectly flat roof plane rather than lined up by the ends of the rafter cords. You will trim between 3 to 6 inches from the end of each scissor truss tail.