Waterproofing of raft foundation

Waterproofing of raft foundation

Waterproofing of immersed underground structures requires permanent dewatering during the execution phase and continues until the pressure caused by the weight of the concrete structure exceeds the hydrostatic pressure exerted by the water table.

The types of foundations designed for such structures is most of the time raft foundation with or without piles, or a combination of the raft and pile caps, depending on the bearing capacity of the soil. In such cases, the waterproofing is called tanking as it envelops completely the structure from the bottom to the water table level and preferably to the ground floor level. The waterproofing of the vertical part will start only when the full foundation raft/pile caps are cast.