Maintenance & Refurbishment


Roofing Feature


BS 8612 has provided reassurance that if Standards are met and manufacturer’s instructions are followed, there should not be a need for a return to make repairs


down the gable wall of the property, leaving an unsightly staining. Industry experts soon realised that the increase in verge products on the


market not adhering to any standard was proving difficult – specifiers didn’t know they were selecting a trustworthy quality system with longevity. This is where the start of BS 8612 came into fruition, with all the common factors of dry-fix installs being discussed and how these should and could be overcome to improve current builds. This gives all parties involved in the selection process, from contractors to end users, the confidence that what is being used on a project is up to a certain level of expectation and not a weak solution. The British Standard BS 8612 is set out to ensure that dry fix roofing


resulting in a less secure fix. The introduction of a face fixing batten bracket is a key point and improves the fix dramatically. If there was no barge board for the starter unit to be installed to, the contractor was forced to come up with other ways of securing the eaves unit – one way was with the use of some wire threaded through the unit and secured to a nail or screw to the fascia board. Once the system was installed these issues were not clearly visible, so were


‘out of sight, out of mind’ until the bad weather hit and failings became more obvious causing problems for contractors, and specifiers. The most common visible issue that stood out was the allowance of rainwater to either drip or run


Keeping dry… By Ian Weakford, Sales & Marketing Director @ Hambleside Danelaw W


ith the increasing unpredictability of British weather, particularly in winter, ensure you- and the properties


you manage- stay dry. Extreme winters have challenged roofing


product manufacturers to develop solutions to reduce the impact of the weather, particularly wind. It causes slates and tiles to dislodge, underlays to vibrate, and can lead to rain ingress. Even winds as “low’ as 20mph can cause damage. In most situations there is therefore a


requirement to use dry, rather than ‘wet’, fix solutions, so that the roof details, particularly ridges and hips, remain intact, and therefore weatherproof, regardless of the extremes of winter weather. Because the fixing method is dry, remedial work can be carried out almost regardless of the weather; ‘wet’ methods, such as mortar, by contrast need a degree of decent weather for the mortar to cure before being subjected to load. The realisation of the practicality and durability


of dry fix solutions has seen a growth in their popularity. This in turn has led to a growth in the number of mechanically-fixed products available, with a corresponding diversity of quality and performance. It is a case of ‘you get what you pay for’: products with a higher unit cost are usually manufactured and tested to higher quality standards, so can be expected to be easier to use, and to perform better. Thus the perceived higher


cost can actually result in a saving, in that the product will withstand the loads, remain in place, and reduce repairs. To put it into perspective, storm Doris in 2017 saw a 300 per cent increase in the cost of insurance claims from wind damage. Inevitably, in line with these market force


changes, a British Standard has been introduced. BS8612:2018 Dry Fixed Ridge, Hip and Verge Systems for Slating & Tiling: Specification aims to create minimum performance & durability standards for dry fix products used in these areas. But making a roof weatherproof has to be


balanced alongside allowing the roof to “breathe”, to avoid any interstatial condensation. Debate continues to rage about the best way to achieve this, with the arguments primarily focusing around the underlay. Should it be airtight or permeable? Because it is a topic so debatable, our view is always to follow a ‘belt and braces’ approach: vapour permeable underlay AND ventilation. Current Regulations require the ridge to be mechanically fixed, so the small, additional material cost is more than outweighed by the cost of fixing a roof riddled with damp and rot from condensation. A roof does need to breathe, so ventilation


openings will need to be provided anyway. Some argue that air permeable membranes are more effective in allowing the dissipation of moisture, but their use needs to be considered in the increased tile fixing specification as there will be


42 | HMM October/November 2019 | www.housingmmonline.co.uk


greater load on the tiles- another reason to rely on mechanical fix rather than ‘wet’ which is so dependant on the quality of the mix, the quality of application and the weather. As with dry fix products, membranes too vary


in quality and price, and again, you get what you pay for. With the recent years of high winds, the UK has now been zoned by wind uplift. Most membranes are not certified for use in all zones, unless particular attention is paid to the fixing method i.e. restraining battens or taped joints. To be sure your roofs will perform, the


best solution is to check your spec. with the manufacturer, and be sure you read the small print, to understand any limitations of use, and to ensure the roofing contractor quotes for and installs what you have specified.


01327 701900 www.hambleside-danelaw.co.uk


products pass the physical demands like vertical load for wind uplift (verge), rain drainage (verge) as well as an accelerated colour fast test, for aesthetics. The full independent range of tests are carried out by the experts at the Building Research Establishment (BRE) in Watford (although some larger companies may have the facilities to run their own) and are calibrated to indicate which of the products can be installed within the correct wind zones, as long as the full system has been used and installed as per the manufacturer’s instructions. The testing procedures have given a greater confidence in the products,


regardless of who made them, for the specifier, installer and developer. They have provided the knowledge and reassurance that if Standards are met and manufacturer’s instructions are followed, there should not be a need for a return to make repairs.


Keith Plummer is technical manager at Ubbink


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