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RCI Feb 2018

Upping the standard of dry fixing Publication of the first British standard to govern dry fixing has now been launched. BS 8612 will at last bring quality requirements to a sector, which has seen more than its fair share of cheap products entering the market in pursuit of quick market share. Graham Copson, technical manager at Klober, explains all to RCI readers The National House- Building Council and the British Standards Institution made considerable strides towards reducing mortar-associated roofing complaints by requiring the addition of supporting mechanical fixing on all roofs. The continuing upward trend in newbuild claims under the Buildmark Warranty had become unsustainable and their decision, supporting a growing lack of confidence in traditional roofing practice, provided the perfect stimulus for greater use of dry fixing. In the absence of a British standard, however, merchants and roofers have been encouraged by some manufacturers to think that their products offer broadly similar performance to those with a proven track record. With no need to publish technical data in support of what are frequently unsustainable performance claims there has been tacit acceptance of misinformation. This has made telling good products from bad extremely difficult, and the lack of effective governance has, not surprisingly, prompted an increasing number of complaints and failures. The irony is that products for which, lengthy guarantee periods are being claimed, are clearly proving totally unfit for purpose. The absence of consistent product information has meant that the understanding of factors affecting dry fixing performance remains low. Some merchants have done little more than push complaints back to suppliers, while using procurement criteria which take little account of either quality or contractor preference. Apart from perpetuating problems, this also undermines the efforts of those roofers, manufacturers, and industry organisations who are continually striving to improve industry standards. BS 8612 will set out installation conditions for products including dry ridge, hip and verge, but not valleys or eaves, for which too many types exist. Of course, reputable manufacturers have always made clear their fixing requirements which, for a product such as a verge, are broadly consistent whoever’s product is used. Typically, battens are extended by a given length beyond the wall so that renders cannot be finished up to verge tiles. The need for a standard is clear, however, Klober has recorded a number of complaints relating to staining of walls as a result of bad practice. By taking render up to the verge, this often occurs as a result of moisture leaking through and running constantly down the face. During prolonged periods of bad weather, it can also lead to walls becoming saturated for long periods, causing the render to lift. If a mortared verge is replaced, existing battens which do not extend far enough beyond the wall are often reused, and in extreme cases, are cut flush against it. Clear definitions of material and performance requirements for dry fixing components will be included. One element for which this is particularly needed is the ridge roll backing. Clear variations in ridge and hip fixing quality is caused by this as anything less than a butyl adhesive of a suitable thickness will not provide a strong and lasting bond. The ridge is not only the most exposed area of a roof, but must perform in the most extreme conditions. It must also be suitable for the uneven, rough and often dusty surface, which is typical of roof tiles. However, though BS 8612 will define such requirements, in-house testing is still likely to be accepted. This again brings into question (as it did with BS 5534) data which will be published in support of performance claims. Current use of terms such as ‘superstrength’ 092 FEBRUARY 2018 RCIMAG.COM adhesive backings are too often taken at face value though. In the face of claims of extended performance guarantees, it is hard to blame roofers for doing so. Many products now sold are clearly not being tested to a level consistent with long-term performance so the standard will provide the much needed requirement for detailed substantiation of performance claims. The only reliable Project1_Layout 1 PITCHED ROOFING information will be that supported by independent third party testing by trusted organisations such as the BRE. Only a minority of suppliers have felt sufficiently confident to submit their products to such scrutiny. Ultimately, only time will tell the extent to which dry fixing quality will be improved to the point where those sold are consistently fit for purpose. Considerable time has been spent in drawing up the standard, so the added emphasis on factors such as weathertightness and durability should begin to provide a degree of differentiation. It should also prevent products being described as universally compatible when they are clearly anything but. www.klober.co.uk S Page 1 SMITHBROOK_Q 03/10/2017 11:11 Page 1 Glazed Clay Roof Tiles to match existing or in ANY COLOUR of your choice We offer "Sterreberg", "Courtrai", "Pottleberg", Double & Single Roman profiles, in glazed and unglazed finishes Tiles shown are not to scale Smithbrook Building Products Ltd PO Box 2133, Shoreham-by-Sea, BN43 9BD Tel: 01273 573811 Fax: 01273 689021 Email: info@smithbrookproducts.com www.smithbrookproducts.com


RCI Feb 2018
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