Raft foundation is reinforced concrete Slab which founds the entire supporting member of structure like column, shear wall etc. Foundation construction of this type is required where made up ground, expansive clay soil or marshy site are chosen to found a heavy structure.
Raft foundation slab generally covers entire contact area of structure like a floor and foundation slab projects 30 cm to 45 cm distance from outer wall/basement wall of the structure towards all sides. But when property line merges with basement wall, the projections are sometimes avoided.
previous post, the beams are cast after the slab with necessary precaution to provide construction joints. Further continuation is commenced after the proper curing of the raft slab and beams.