How to Identify a Load-Bearing Wall

Load-bearing walls in houses almost always assist the structure in the support of the roof. The best way to identify a load-bearing wall is from underneath the house or in the basement. Sometimes load-bearing walls are identifiable from the attic or by examining the exterior of the house.

Interior load-bearing walls can be identified by noting how the trusses are constructed to carry the weight. If there are diagonal braces that push some of the weight of the roof to a central or other interior wall, this is a load-bearing wall. Underneath the house or in the basement these interior walls will rest on a central beam of wood or steel. This beam will support the floor joists and the load-bearing wall. It will rest either on concrete piers or a combination of steel or wood and concrete.

Outside walls almost always are load bearing in any house. Overhead trusses distribute the weight of the roof to the walls that run parallel to the peak of the roof. On the walls that stand perpendicular to the peak or ridge of the roof, the end trusses sit with their weight as if they were a special add on to the top of the wall.

If there are unique architectural features such as a large gable extending over an open area of the structure, special interior walls may be constructed with a significant beam to bear the weight of truncated trusses. The studs at each end of this wall will be at least doubled to help convey the weight to beams in the basement or piers place beneath them into the ground below the frost line.

Exterior load-bearing walls will have a double top plate constructed from the same size lumber as the wall studs. Usually these are either 2x4 or 2x6 timbers. The plate will run the entire length of the wall. While the wall will generally rest on the subfloor, it is ultimately placed directly over the foundation. This lets the wall utilize the strength of the foundation to prevent cracking and settling under the best circumstances.