Diaphragm and Piled Wall Waterproofing Systems

Diaphragm walls and contiguous/secant piled walls are commonly used in the construction of large commercial basements. Because of the way these types of wall are constructed, it is only possible to position the waterproofing on the internal face of the wall. Waterproofing solutions for these types of wall are therefore similar to those used to waterproof internal basement walls (see above) although they are adapted to take account of the higher levels of water ingress that might be expected in larger basements - e.g. the cavity drainage waterproofing system shown in the diagram on the left uses the large-stud-size Oldroyd Xv20 drainage membrane to provide a larger drainage cavity than would be the case with standard drainage membranes.

An alternative approach to waterproofing contiguous and secant piled basement walls is to sandwich a layer of Vandex Super crystalline active waterproofing slurry between a layer of shotcrete and a layer of insitu concrete.

The choice of waterproofing system will be influenced by the type and quality of the piled walls used in the basement construction and the level of water resistance that they provide. Some types of piled wall are only intended as enabling works and will allow significant water seepage. In these cases cavity drainage waterproofing should not be relied on in its own right as the piled wall is not providing "primary resistance" to water ingress. In such cases a combined waterproofing system incorporating Vandex Super and Oldroyd Xv20 might be considered as shown in the example above.