New build water proofing

High prices and an increasing strain on land stock has meant builders and architects are considering alternative options to extend and increase properties.

Spurred on by the government Housing Green Paper 2007 and the targets set, new build basements are becoming an increasingly popular choice. A basement increases potential living space in new dwellings without dramatically infringing on the land.

Historically the cost of construction and the concern for leaks was a stumbling block for basement construction in new build properties but with improving construction techniques and waterproofing technologies the cost of not constructing a basement will in the long term, be the dearer option to the Homeowner.

The use of construction materials such as Insulated Concrete Formwork (ICF), offer increased insulation levels subsequently the energy savings make such construction economically viable. Additionally, installing Rain Water Harvesters ensures the basement structure is Eco efficient.

The second identified problem of waterproofing is now a thing of the past and with the development of waterproofing technologies Wykamol basement contractors are happy to issue 10 year insurance guarantees to their workmanship and BBA approval documents state our cavity drain membrane products will last the lifetime of the structure.

In the British Standard document for structural waterproofing, BS8102, cavity drain membrane is referred to as Type C category of waterproofing which is regarded by the NHBC as the lowest form of risk in basement construction waterproofing. Risk is the key word a qualified waterproofing Surveyor or Architect takes into consideration when putting a waterproofing design together.

The design considerations of a new build basement factor in the soil conditions including contaminants, the water table position the nature of the structure and intended use of the basement. The extent of the risks leads to the choice of waterproofing materials and design.

Consideration needs to be given to failures in externally applied waterproofing systems such as bitumous sheet bonding or liquid applied membranes which in the event this occurred, would be difficult to repair. The installation of internally applied cavity drain membrane and drainage system which is endorsed by NHBC is also the system that is regarded as easiest to maintain and easiest to remediate.

Cavity drain membrane can also be applied externally and with the addition of an external land drain positioned correctly this helps to remove water from around the basement structure and relieve a head of water forming against the structure. With economic viability and pressure to maximise the use of new build land, basement construction is a real consideration for the Homeowner.