In smaller buildings, and occasionally in large structures, the perimeter slurry walls or other vertical slab systems assist in the load-bearing structural support. In most tall buildings, the slurry walls at the edge of the foundation merely hold out surrounding earth and water, and play little role in structural support; therefore these are not counted as part of the foundation system. When this foundation type is applicable to large buildings, it is usually found in combination with some other foundation type.

The wall or vertical slab participates in carrying the structure above. Holding surrounding soil and water back alone does not establish this foundation type.

A load-bearing wall can operate together with another foundation system. Its structural contribution remains distinct from a perimeter retaining wall with little building-load support.