Types of Groundwork
Piled Rafts / RC Slabs
A raft foundation consists of a raft of reinforces concrete under a building. This foundation type is described as a raft in the sense that the concrete raft is cast on the surface of the ground which supports it.
Raft foundation may be used for buildings on compressible ground such as very soft clay, alluvial deposits and compressible fill material where strip , pad or pile foundations would not provide a stable foundation without excessive excavation. The reinforced concrete raft foundation is specifically designed to transmit the whole of the building from the raft to the ground where the small spread loads will cause little if any appreciable settlement. There are in fact two types of raft foundation commonly used are the flat raft and the wide raft.