Roof trusses are prefabricated wooden roof members that combine the rafter and ceiling joists of conventional framing into one structural piece. Although a roof truss may be heavier and more difficult to manoeuvre onto the top of the building than conventional framing lumber, once there it can easily be slid into position and secured. Although trusses may be more expensive that a conventionally framed roof, many builders use roof trusses to save time and labour costs. Once the side walls are marked with the positions of each truss, the trusses are then secured to the walls.
Position the bottom horizontal member, or bottom chord, of the truss on the marks on each side wall. Have a helper hold the truss in place.
Hold a 16D common nail at a 45 degree angle approximately two inches up from the bottom of the bottom chord of the truss.
Hold the bottom chord down firmly to the wall top plate with one hand. Use a framing hammer and drive the nail through the truss and into the top plate of the side wall until the nail head is flush with the surface of the bottom chord of the truss.
Toe-nail the opposite side of the bottom chord to the same top plate in the same manner.
Repeat the procedure to secure the other end of the truss to the opposite side wall.
The first truss nailed into position should be the gable end truss, which is installed at the end of the building. Once secured to the side walls, the truss should be plumbed with a builder's level and braced into position with scrap lumber. Once the gable end truss is secured in the same manner to the opposite end of the building, all remaining trusses can be secured and braced to the gable end trusses with scrap lumber. Use of coated nails will make a more secure connection, but in the event you need to remove a nail, they are much harder to back out.