The new test measures the ability of an underlay to resist the wind. This is significant because of the role the underlay plays in maintaining the integrity of the roof structure. When wind blows over a roof, uplift forces act on both the underlay and the tiles. The primary purpose of an underlay is to reduce the force acting on the tiles by taking more of the wind load itself. However, if the underlay stretches too much when subject to wind pressure – or balloons – and touches the back of the tiles it ceases to perform this function.
This can cause the tiles to be blown off the roof in high wind conditions, such as those seen in the UK in the New Year.
The new test standard is expected to be implemented in July 2014 along with the publication of the new revised BS 5534 standard. This would mean that all third party accreditation bodies, such as the British Board of Agrément (BBA) and Building Research Establishment (BRE) will use the same test going forward when certifying underlays for their fitness for purpose.
Wind conditions vary considerably throughout the UK and the draft standard also includes provision for a new labelling system for underlays that will outline the suitability of the product for specific geographic regions.
Assuming that the standard includes these provisions when the final version is published later this year, we believe that the nature of the underlay supply market will be significantly altered. Cheaper, lightweight underlays that stretch excessively are likely to have restricted use and manufacturers will look to develop better quality underlays solution that will be suitable everywhere in the UK without restrictions. This development is likely to be driven by merchants who are unlikely to want to stock several different types of underlay to cater for regional variations.
In the new housing sector we anticipate that the new underlay standards, if implemented, are likely to be enforced by the National House Builders Council (NHBC), which continues to drive up its own standards to address the rising cost of roofing claims against its Buildmark Warranty.
BMI reveals roofing’s top 20 for the Apprentice of the Year final
Twenty of the country’s best roofing apprentices are gearing up for the two-day final that will see two of them awarded the prestigious title of either pitched or flat roofing BMI Apprentice of the Year 2019. Success in the competition identifies an apprentice as a stand-out individual and as someone with a bright future in the sector. Previous finalists have gone on to win multiple other awards, founded their own businesses or represented the industry and recruited new entrants as Construction Ambassadors with the CITB.
A PIECE OF HOME DELIVERED BY BMI REDLAND CAMBRIAN SLATE FOR PIONEERING HOSPICE
A first in the UK for its innovative use of reconstituted slate in a modern interlocking roofing material, the BMI Redland Cambrian Slate combines great traditional looks with great durability and cost-effectiveness; and so provided an ideal solution for roofing Butterfly House, an important and sensitively-designed £4.8 million hospice in High Wycombe.
Winners and contenders alike praise the BMI Apprentice of the Year competition
Each year, the BMI Apprentice of the Year competition helps apprentices on their journey to build their future career – by helping them with better business understanding, stronger communication skills and improved confidence. These are just some of the benefits that past winners and finalists of the BMI Apprentice of the Year competition have received and, as entries for the 2019 competition continue to arrive, some of past finalists have been reflecting upon the experience and what it taught them.