Pressure Slab

What is a Pressure Slab?

Definition of Pressure Slab in Construction
Concrete slab, that is designed to withstand an upward lift, caused usually by hydrostatic pressure that builds under the slab.

The pressure slab is heavily reinforced and normally of a thickness greater than commonly designed for a slab that will not have any hydrostatic pressures beneath. In some instances the use of rock anchors drilled under the slab, and attached within the slab itself, are used to further increase the hold down forces within the concrete slab. In most cases, the use of an under slab drainage system to eliminate the water and therefore the pressure is installed, in addition to the pressure slab, to further ensure the slab does not fail due to hydrostatic pressures being built up under the slab.

The engineering and construction of a pressure slab, that is capable of withstanding high upward lift, is both expensive and time consuming. However lack of proper engineering for this type of site condition can lead to extensive damage to the slab and possible failure of the entire foundation system.