Jacking Raft.

The jacking raft is used in areas where the expected subsidence would tilt or distort the structure to an unacceptable degree and where re-levelling of the raft produces an  economic and viable foundation for the design conditions.

The jacking raft is used in locations of excessive or unpredictable subsidence, for example, in areas subjected to brine or other mineral extraction. A typical jacking raft for a domestic property is shown in Fig. 9.30.

Fig. 9.30 Jacking Raft.