How to Keep Truss Tails in Line

Measure and layout the locations of the trusses along the top plates of the building's exterior walls. The trusses are spaced 16 to 24 inches apart form one another, depending on the local construction codes, and the type of building. Check with local building authorities to verify the specifications in your area.

Install the gable trusses at one end of the building's roof first. The gable truss must be nailed to the top plate. Attach long 2-by-4's to the gable truss, and run these down to ground level. These long braces keep the gable truss in place, and plumb as the reference for the remaining trusses.

Install the trusses in order, nailing each one in place by nailing the bottom cord to the top plate of the wall, and nailing 2-by-4 braces diagonally across the top cord to keep the trusses from falling over.

Lay the level across the top cords of the trusses to make sure they create a flat and level roof plane. When you lay a level across two or three trusses in a row, the level should touch each truss. A space up to 1/2 inch is OK, because the roof trusses may have minor imperfections between them. However, if one truss is more than 1/2 inch too high, or too low, bump the truss to the right or left to eliminate the problem. Do not worry about the rafter tails alignment until all the trusses are installed.

Drive a 16D nail into the rafter tail on the first gable truss, and attach a chalk line to this nail. Stretch the chalk line across the length of the building. At the other end of the building, place the chalk line in the same location on the rafter tail. The chalk line creates a straight line across the tops of all the rafter tails. Snap the line to create a chalk mark on each rafter tail.

Using the quick square, draw a vertical line on each rafter tail at the point marked by the chalk line. Cut the rafter tail off on this mark, and then each rafter tail will create a perfectly straight line along the side of the building.