Roof Truss Support Walls

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.

Roof truss support walls.

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. Structural support usually a beam or wall that is designed by the building designer to carry the truss reaction loads to the foundation. By eliminating interior bearing walls trusses also save the cost of interior foundation walls interior partition top plates and headers. Roof trusses support a roof s weight by transferring the weight load downward and outward to the building s bearing walls.

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. Some roof truss types such as stub and dual pitch contain no center and therefore lack central support. Engineered roof truss systems may be designed to eliminate the need for load bearing walls or change where the bearing walls are located. Flat the most economical flat truss for a roof is provided when the depth of the truss in inches is approximately equal to 7 of the span in inches.

This means that at the top floor of a house the interior walls may not be supporting the weight of the roof structure and the weight of snow. 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. A gable truss isn t structural and needs a continuous bearing support underneath such as a beam or wall. Nearly all types of trusses used in roofs from kingpost and queenpost to bowstring and cambered possess a central support beam.

Usually trusses are put 24 inches apart. 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. You will need an engineer involved in this since many contractors will tell you anything to get the job.