Non Load Bearing Roof Truss

Roof trusses support a roof s weight by transferring the weight load downward and outward to the building s bearing walls.

Non load bearing roof truss.

The roof trusses are too long to span the whole house so the load bearing wall runs down the center of the house to support the trusses at the perpendicular intersection in the middle. It can take various forms and often used for aesthetic purposes adding height and focal interest to the ceiling. On a recent project with precision end trimmed studs the contractor suggested using a single top plate at the non load bearing walls so all the studs could be the same length and not have an issue at non load bearing walls. We usually build on the exterior walls set the trusses and do all of the chord blocking and truss bracing before buildin.

An example of a non load bearing partition wall can be seen on the left. Actually a quick way to determine if the wall is bearing is to cut hole at the top to see if it has one or two top plates. This type of truss is perfect for the dining room living room great room and kitchen. One top plate and a space between the bottom chord of the truss and the top of the wall non load bearing.

If there are two plates refer to an engineer. For example a gable end truss may be designed with support members that transmit the roof weight load outward to the side walls allowing the end wall directly below it to have breaks or openings in it that would otherwise be impossible. An example of a load bearing wall call be seen on the right. I always use details to show separation and clips between non load bearing walls and trusses.

Non loadbearing walls as designated shall not carry any truss loading and shall not be packed to touch the underside of trusses see figure below. When joists trusses are perpendicular to the wall and bear on the top of the wall that wall is bearing wall. One way to ensure non loadbearing is to set the non loadbearing walls at a lower level than the loadbearing 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.

If the wall in question is parallel to the joists trusses it will likely not be load bearing. Engineered roof truss systems may be designed to eliminate the need for load bearing walls or change where the bearing walls are located.