Graham Copson of Klober explains the reasons behind the introduction of a new British Standard for the increasingly popular method of dry fixing.
Following widespread problems associated with use of mortar on roofs, publication of a new NHBC Technical Standard and an update to BS 5534 in 2015 prompted a dramatic increase in dry fixing of ridge, hip and verge. The downside is that such market conditions tend to attract suppliers keen to capture quick market share and, inevitably, this brings with it variations in quality.
The absence of a British Standard governing these products will finally be addressed later this year when BS8612 is published. Its overriding aim will be to prevent cheaper products being marketed without technical data to corroborate performance and long-term effectiveness.
Ultimately, product selection is the roofer or builder’s responsibility but awareness of those which minimise risk of premature failure and unplanned maintenance can only be a good thing for all concerned.
This is particularly important given the fact that, in a short space of time, the widening choice of dry fixing materials has effectively encouraged a ‘commodity’ approach to procurement. The result has been an increase in the number of complaints and failures.
It is worth emphasising at this point the extent of problems associated with mortar fixing prompted British Standards and the NHBC to decide that it could no longer be relied on as a sole means of fixing. Complaints to housebuilders may continue to attract media attention but tend to focus on deficiencies of particular companies rather than products. Less well known is the fact that the number of claims under the NHBC Buildmark warranty had reached such a level that underwriters felt the cost was no longer sustainable. With evidence suggesting that the upward trend was set to continue something had to be done.
Being aware of the consequent boost to sales that such a move was bound to provoke, the decision to produce a British Standard specifically for dry fixing was only a matter of time. It will cover ridge, hip and verge products, but will not extend to valleys and eaves. Even so, manufacturers will have to conform to specific aspects of technical performance in relation to features such as durability and weathertightness. Just as importantly, greater transparency is likely to be required in terms of supporting technical data and it is also likely that the type and quality of accessories such as mechanical fixings will be specified.
The problem for homeowners, landlords and contractors alike however is that, for now at least, it’s impossible to know which products can be relied on. Despite this, some elements which often separate better products from the rest can be checked with relative ease.
A good example of this is the backing used on a ridge or hip roll, as only the highest performing adhesives will bond securely to dusty surfaces and withstand severe weather. A backing such as Butylon, which is used on the Roll-Fix ventilated dry ridge/hip manufactured by Klober, is designed to bond immediately to provide instant protection. Any adhesive which can’t do this is at risk of early failure as it will be affected by rain and wind while curing.
With some manufacturers providing little or no information on the projected design life or testing of their products this is all good news. At the moment, the only certain way to be sure of performance is to look at what has stood the test of time.
This is not to say that all lower cost products should be avoided. However, it is legitimate to examine the likely means by which the cost has been reduced as the risk will undoubtedly be greater. Of course, there will always be pressure in the supply chain to keep costs as low as possible but for those whose main selling point is price it may have been achieved through the omission of components from kits, ‘cro’ clips to secure small tile cuts on hips being a good example.
A ridge or hip kit should include all the accessories a roofer needs to fit a given length of tiles, something which also provides a simple means of product comparison.
A high proportion of dry fix sales are replacing use of onsite silo mortar and for merchants such products present clear potential for continued growth. It should be in their interest to ensure the products they supply are ones that contractors will keep coming back for but at the moment, they have an unenviable task.
The development of features such as universal seals for use with round or angle ridges/hips adds further differentiation in terms of quality but it is clear that an absolute definition of what is required to guarantee lasting performance is needed.
For the moment, with demand for such products at an all-time high in the UK housebuilding sector, the reputation of dry fixing is not being helped by products available on the market which are being sold with little more than a promise of performance.
Graham Copson is technical manager at roofing solutions manufacturer Klober