Wide toe rafts foundations

Where the ground has poor compressibiliry and the loads on the foundations would rewuire a thick & uneconomic flat slab , it is usual to cast the raft as a wide toe raft foundation

1. Recommended for buildings in areas subject to mining subsidence ,
2. Cast on a bed of fine granilar material 100mm thicj so that the raft is not keyed to the ground
3. THe raft is cast with a reinforced concrete stiffening edge beam from which a reinfoced concrete toe extends as a base for the external leaf of a cavity wall.

THe cavity wall is on side of the houses ,and the edge beam with wide toe to support the wall .Then inside the buildings still have an internal load bearing wall , the first layer is 50mm finish ground and the seconf the the reinforced concrete raft and the third is the damp proof membrane and the last 1 is100 mm hardcore with 50mm blinding .