Roof Truss Support Walls

Some roof truss types such as stub and dual pitch contain no center and therefore lack central support.

Roof truss support walls.

Structural support usually a beam or wall that is designed by the building designer to carry the truss reaction loads to the foundation. A gable truss isn t structural and needs a continuous bearing support underneath such as a beam or wall. They do this by means of top chords which are sloping members that extend from the peak of the roof to the top of the exterior walls at the eaves. Truss roofs are typically designed to use some interior walls as mid span support to save on costs associated with making the truss larger stronger.

Gable trusses are more expensive than common structural trusses because more lumber is required. Nearly all types of trusses used in roofs from kingpost and queenpost to bowstring and cambered possess a central support beam. Roof trusses support a roof s weight by transferring the weight load downward and outward to the building s bearing walls. Elements that make a roof truss bearing.

By eliminating interior bearing walls trusses also save the cost of interior foundation walls interior partition top plates and headers. Roof trusses can span much longer distances than joists so if you have a gable roof there is a good chance that it can span between exterior walls and not require an interior bearing wall for support. A gable truss sits on the end wall of a structure and has vertical studs every 2 feet or 16 inches. To hold them up until the decking of the roof is placed on top a 12 foot 1 inch by 4 inch piece of lumber is used.

As each truss is put up on top of opposite walls it must be put up straight and supported while the next truss is put up. Engineered roof truss systems may be designed to eliminate the need for load bearing walls or change where the bearing walls are located. Usually trusses are put 24 inches apart.