Foundation is part of a structural system that supports and anchors the superstructure of a building and transmits its loads directly to the earth. To avoid damage from repeated freeze-thaw cycles, the bottom of the base should be below the freezing line. The foundations of low-rise residential buildings are almost all supported on extended footings, wide bases (usually concrete) that support walls or pillars and distribute the load over a larger area. A concrete-grade beam supported by footings, pillars or piles insulated at ground level can be placed, especially in a building without a basement, to support the outer wall. Extended footings, in a greatly extended form, are also used for high-rise buildings.
