The function of any raft foundation is to spread the load of the entire area of the site. A raft foundation normally consists of a concrete slab which extends over the entire area. it may be stiffened by ribs or beams incorporated into the foundation.
They are made up of concrete and heavily reinforced with steel, so entire foundation will act as a unit the raft foundations have the advantage of reducing differential settlements as the concrete slab resists differential movements between loading positions.
