A classification is as follows: -pad or spread footing used under individual columns; -special footings such as combined, balanced or tied bases and special shaped bases; -strip footings used under walls or a row of columns; -raft or mat foundations where a large slab in flat or rubbed construction supports the complete building; -basement or cellular raft foundations; this type may be in one or more storeys and form an underground extention to the building that often serves as a carpark.