How to Attach Trusses

Measure from the end of the wall cap or foundation sill, and place equal interval measurement marks. If installing floor trusses, space the marks 16 inches apart. If you are installing roof trusses, measure from the top of the wall plate, spacing the measurements 24 inches apart along the wall and beginning at one end. Place the measurement marks on opposite sides of the wall or foundations, which will represent both ends of the truss placements. Place an X on each of these marks to represent center marks.

Measure back 3/4-inch from each mark, and square the mark across the wall top plate or foundation sill plate. This mark represents the outer edge of the truss. Align each truss edge with this mark, with the first set of marks placed with a tape measure landing in the center of the truss. The center marked X will serve as a reference for the placement of the center of the truss, and the 3/4-inch edge mark will help you align the edge of the truss.

Set the first truss on the end of the foundation sill or wall plate with the outside edge flush with the end of the wall or sill. Drive a 16-penny nail in at an angle, beginning about 1.5 inches up from the bottom of the truss where it rests on the foundation sill or wall plate. Repeat on the opposite side of the truss where it rests on the opposite wall plate or foundation sill. Place the next truss, aligning the outer edge with the preplaced mark. Check that the X is located in the center of the truss while the outer edge is resting on the square mark placed earlier. Insert a 16-penny nail at an angle on both sides of the truss where it touches the foundation sill or wall plate.

Attach 8-foot 2-by-4s on top of the trusses to create a box and tie the trusses together. Remove these temporary supports when attaching plywood decking. These supports will secure the truss frame until it can be covered.