A loa-bearing wall or bearing wall, is one in which a wall of a structure bears the weight and force resting upon it, conducting the vertical load from the upper structure to the foundation. A bearing wall is opposed to a curtain wall, which uses the strength of a sub-wall to bear the weight of the curtain such as the brick facade on a skyscraper, and superstructure, usually a steel frame, to carry the weight of the floors and walls inside the curtain walls protection. The materials most often used to construct load-bearing walls in large buildings are concrete, block, or brick.