The raft foundation is a very commonly used type of foundation system. Raft foundation is also known as Mat foundation. Definition of raft foundation along with working principle, when to choose raft, types of raft foundation, materials of raft foundation, raft construction steps etc are discussed below. What is the Raft Foundation? Raft foundation is actually a thick concrete slab resting on a large area of soil reinforced with steel, supporting columns or walls and transfer loads from the structure to the soil. Usually, mat foundation is spread over the entire area of the structure it is supporting. Raft foundation is generally used to support structures like residential or commercial buildings where soil condition is poor, storage tanks, silos, foundations for heavy industrial equipment etc. Working Principle of Raft Foundation To get a better idea about when to use raft foundation, it is important to understand how raft foundation works. Let’s get a quick review of its