Roughly two-thirds of the claims reported were in relation to external wall and roof issues. Claims relating to external walls were up by more than 150% compared to ‘normal’ levels. And shoddy workmanship was to blame.
NHBC, the leading warranty and insurance provider for new homes in the UK, is now planning a series of free seminars to increase industry awareness of problems relating to external walls.
“Root cause analysis of claims from this period revealed that workmanship issues were the primary cause,” said Chris Derzypilskyj, NHBC’s technical projects manager. “Therefore the aim of these seminars is to provide detailed information on best practice, focusing on key areas such as structure, render, cavity trays and DPCs, to provide a national and regional overview of the claims experience as well as feedback on current site experience.”
Problem areas that the industry needs to address, according to the NHBC, include:
Render: Consistently over the last four years the main failures have been de-bonding from the substrate, shrinkage and thickness/number of coats (background preparation, application and cracking)
Cavity Trays and damp proof courses: Incorrect installation of horizontal and stepped trays – including linking to flashings
Insulation: Poor installation of product e.g. at corners, cavity trays/lintels, wrong product for exposure, retention within the cavity and reduced cavity widths. Membranes and product positioning within timber frame construction and issues with interstitial condensation will also be included.
NHBC’s external walls seminars will take place throughout September. For details, see