10-03-2017, 02:18 PM
Raft foundations (sometimes known as mat foundations) are a large slab of concrete that can support a number of columns and walls. The slab extends throughout the entire building or at least a large part of it, which reduces contact pressure compared to traditionally used girdle or trench bases. Due to the speed and volume of houses required after World War II, the base of the raft was widely used. The base of the raft was cheaper, easier to install and most importantly, it did not require as much excavation as the usual strip bases. When building regulations were introduced in 1965, there were no generic standards for raft foundations, as they were for strip foundations.
