The National House Building Council (NHBC) recently reported that claims on basements built since 2005 have cost the UK housing industry nearly £21 million, affecting 890 homes.
Research conducted by the NHBC found that tanking defects have been the most common cause of basement claims since 2006. In addition 28% of sites surveyed in 2012 had either high or unknown water tables, yet proposed a Type A or B construction which may not have been suitable in such a situation, highlighting the need for improved advice covering all methods of construction.
Mark Jones, NHBC’s Group Head of House-Building Standards, said: “Following on from our report into basement problems and subsequent new guidance we believe that working with the wider industry will help us inform and support the sector and ultimately help to improve standards and reduce claims.
“Our analysis of basement issues included surveying hundreds of live sites and following the development of recent guidance we will continue to monitor work on site in order to gauge the impact of the this advice .”
In response, the PCA’s Structural Waterproofing Group is to hold a strategy meeting on 29 October.
The group has been conscious that it currently only represents those involved in Type C waterproofing – that is drained protection systems for basements that are often used in basement conversions and renovations.
It is now keen to expand and incorporate representation from manufacturers and specialists involved in Type A – Tanking or Barrier Systems and Type B – Integral Waterproofing thus covering all types of basement construction.
Mike Bromley, the PCA’s Technical Manager, said: “BS 8102:2009, the most recent standard relating to the design and build of basements, recommends that a specialist in waterproofing is included in the design team of any structure where usable space is either partly or fully below ground. The PCA’s Waterproofing Design Specialist register makes available to developers, architects and builders a pool of people with specialist knowledge and qualifications able to make recommendations and carry out basement design and construction.
“Expanding membership of the group to those involved in Type A and B basement construction will greatly increase the breadth of knowledge and advice that can be provided to cover all situations.”
In order to be accepted onto the Structural Waterproofing register members must hold the Certificated Surveyor in Structural Waterproofing qualification (CSSW), to demonstrate competence in all aspects of structural waterproofing and have an on-going commitment to developing their skill including through participation in the PCA’s Continuing Professional Development scheme and hold professional indemnity insurance.
In addition they must be a member, or be employed by a member of the PCA, which requires them to submit to ongoing auditing and to observe the Association’s Code of Ethics and standards relating to conduct and behaviour.