Waterproofing New-build Basements and Cellars
When constructing a new basement, it is possible to apply the waterproofing system to the internal (negative) or external (positive) side of the basement wall. In many cases, combined systems are specified to provide enhanced protection. Examples of newbuild basement waterproofing options can be found on our CAD drawings page. To discuss waterproofing options for specific basement structures, please contact our technical department.
Internally applied systems are popular when waterproofing old basements, but can also be used to waterproof new-build basements in situations where access to the external side of the basement is problematic – e.g. when building close to other properties or when using contiguous / secant piling or diaphragm walls to construct the basement retaining walls... Internal basement waterproofing can be carried out using a tanking slurry (e.g. Vandex BB75, Vandex Super, or Vandex Unimortar 1) or using a cavity drainage system (e.g. Oldroyd Xv or Oldroyd Xv 20).
When waterproofing basements externally, we would normally suggest the use of a "dual-layer" system. This consists of a primary waterproofing system (e.g. Vandex Cemelast , Vandex Super , or Vandex Flexbit) protected by a secondary drainage layer (provided by a cavity drainage membrane such as Oldroyd Xv). This secondary layer protects the primary waterproofing system from damage during backfilling. It also lessens the stress put on the primary waterproofing system, reducing water ingress caused by possible imperfections in the application of the primary system and/or structural movement.
To deal with certain site conditions such as high-loam soils, a cavity drainage membrane with a welded geotextile mesh, called Oldroyd Gtx can also be used to provide the secondary drainage layer.
When waterproofing externally, a geotextile ground drain is usually laid around the perimeter of the basement at slab level. This should lead to a sump pump or appropriate discharge point.
Internal / External Waterproofing
An increasingly popular method of providing combined protection is to tank the basement structure externally (e.g. using Vandex Super) and to install a cavity drainage system (e.g. Oldroyd Xv) internally.
There are a number of options available for providing waterproofing to the basement slab. For example, the waterproofing membrane can often be extended underneath the slab using Oldroyd Xs and / or the slab waterproofed using Vandex Super. For further information see our floor slab waterproofing page.
Depending on the method of basement construction, it may be necessary to seal construction joints. We are able to offer a number of joint sealing options for below ground use.
If you would like a technical representative to contact you about basement waterproofing, please call our technical department on 01403 210204 or visit our technical support page.
Safeguard currently offer the following RIBA-Approved CPD Seminars free-of-charge to architects and specifiers on the UK mainland: