New NHBC seminars launched to highlight external wall issues

NHBC, the leading warranty and insurance provider for new homes in the UK, is launching a series of seminars to increase industry awareness of problems relating to external walls.

The events, which are free and available to all NHBC registered builders, have been arranged following analysis of the large number of claims received over winter 2013/14, due to the heavy storms over this period, which led to a 43 percent increase in claims compared with normal levels for the same period in previous years.
Around two-thirds of the claims reported were in relation to external wall and roof issues; external walls being the predominant issue with an increase of more than 150 percent over ‘normal’ levels.

Chris Derzypilskyj, NHBC’s Technical Projects Manager, explained:

“Root cause analysis of claims from this period revealed that workmanship issues were the primary cause.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.”

In greater detail, the main areas of focus are set to include;


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 DPC’s

Incorrect installation of horizontal and stepped trays – including linking to flashings


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.


This will cover bridged cavities, installation of wall ties, movement joints and settlement.

The seminars will take place throughout September and into October, at venues across the country. Full details below;

  • Tuesday 8th September – Cambridge Belfry, Camborne
  • Thursday 10th September – Mercure Abbey Hill, Milton Keynes
  • Tuesday 15th September – National Motorcycle Museum, Birmingham
  • Wednesday 16th September – Leigh Court, Bristol
  • Tuesday 22nd September – Sandown Racecourse
  • Thursday 24th September – Thistle Haydock Park, Haydock
  • Tuesday 29th September – York Racecourse, York
  • Wednesday 30th September – Westerwood Hotel, Cumbernauld
  • Thursday 1st October – Hilton Templepatrick, Belfast

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