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Building Products July 2017

DOORS, WINDOWS AND ACCESSORIES FIXING THE FITTING All over the country, windows are being installed incorrectly, causing problems for suppliers, housebuilders and tenants alike. Chris Coxon explains why and offers a four-step solution for tackling this problem. If you were to walk around 20 housing sites JULY 2017 | BUILDING PRODUCTS 47 right now, how many of them would have windows which were installed incorrectly? Well, incredibly, perhaps all of them. A survey of 21 housebuilding projects of various sizes and run by various companies across the UK found windows installed incorrectly on all-but-one of the sites. Problems ranged from incorrect positioning of the windows in relation to the cavity to missing insulation and cavity closers. Data from new-build housing warranty provider NHBC provides further evidence of poor installation. Issues with doors and windows are the most commonly reported superstructure claims, with sealing-related problems one of the most frequently occurring. The results of these errors can be obvious, in time: damp walls where condensation forms on cold patches, mould growth and even drafts. But in some cases, householders may never know that they are paying far more to heat their home than they could be. According to the BRE, poor workmanship can lead to an increase in U-values – or heat conductivity – of up to 310%. At the heart of the problem is a lack of understanding about how heat is lost through the fabric of a building. Those designing, installing and overseeing the installation of windows and doors need to better appreciate why the details are so important and what those details should be. Some major housebuilders are already taking steps to tackle this problem. We know of one national builder who, having just discovered the widespread problems with window installation, is revisiting the way they specify and procure windows to achieve a more uniform and ‘policeable’ approach. Around five years ago, talk began of the ‘performance gap’ in relation to energy efficiency. Buildings that had been designed to be high on insulation and low on fuel consumption were not performing as predicted once in use. Continued on page 48 >>>


Building Products July 2017
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