A load-bearing wall (or bearing wall) is a wall that bears a load resting upon it by conducting its weight to a foundation structure. By contrast, a curtain wall provides no significant structural support beyond what is necessary to bear its own materials or conduct such loads to a load-bearing wall.
Depending on the type of building and the number of stories, load-bearing walls are gauged to the appropriate thickness to carry the weight above it. Without doing so, it is possible that an outer wall could become unstable if the load exceeds the strength of the material used, potentially leading to the collapse of the structure.
In housing, load-bearing walls are most common in the light construction method known as "platform framing", and each load-bearing wall sits on a wall sill plate which is mated to the lowest base plate. The sills are bolted to the masonry or concrete foundation. The top plate or ceiling plate is the top of the wall, which sits just below the platform of the next floor (at the ceiling). The base plate or floor plate is the bottom attachment point for the wall studs.;