Fastener innovation is said to be helping installers to save time and money on flat roofing installation when using tapered insulation. Kevin Rackley, Product Manager for Flat Roofing Fastener Systems at EJOT UK, explains why…
Carefully designed ‘cut to falls’ (tapered) insulation provides an effective way to ensure sufficient water channelling and drainage on concrete decks. This dual purpose insulation is laid over the deck to provide the necessary gradient in both new build or refurb projects, complying well with thermal requirements and effectively preventing standing water or ponding.
Such is its popularity that up to a third of all flat roofs installed in the UK today use a tapered roof insulation system, partly to satisfy the needs of more complex building designs. However, the variation in the thickness across the area of the roof caused by the gradient does present challenges when it comes to installation – regardless of whether mineral fibre, EPS, XPS or PIR is being used.
Until now, this has meant that when using mechanical fixings, a variety of fastener and stress plate combinations optimally suited for the respective insulation thickness are required. Furthermore, the need to source an extremely long SDS drill can also be as difficult as the physical process of drilling into concrete through this depth of insulation.
The alternative for many installers is to bond tapered insulation to the concrete or screeded deck, which offers simplicity in principle, but it has its own downsides.
Firstly, the feasibility of bonding is dependent on the condition of the deck. This can be a problem in refurbishment projects where conditions may vary across the area of the deck to be treated. And secondly, there is the unpredictable issue of the weather – bonding tapered insulation boards will only be possible when the weather conditions are right, so costly delays on site will result when the weather is poor.
To overcome these challenges and ensure tapered insulation’s use can continue to grow, the product development team at EJOT UK has developed an adjustable mechanical fixing solution which is suitable for insulation up to 500mm deep.
The EJOT UK JBS-R/EcoTek combination brings together the high performing concrete screw (JBS-R 7.5) with a high-quality telescopic tubewasher (EcoTek). This provides one single fastening system which is adjustable to fit the required depth of insulation – anything between 70mm and 500mm.
Using the JBS-R/EcoTek also means fewer fastener / washer combinations are needed – that can easily mean 25% fewer for a slope insulation of 120 to 260 millimetres. This is subject to the application, of course, so a site survey and pull out test is always recommended for any concrete deck – best practice costs nothing.
By developing an adjustable fixing solution in this way, only one embedment depth is needed whatever the thickness of the insulation. The adjustability comes through the innovative way that the EcoTek tubewasher is driven into place using a custom tool with the fastener already in place.
And where the insulation is especially deep, EJOT’s flanged A-cone and extension help to eliminate the awkwardness of drilling deep using standard SDS drills.
Fundamentally, with only one set embedment ever required, the JBS-R/EcoTek fastening system eliminates the need to think about the usual variety of product combinations on site, so the job can be done easier and quicker with an all-round better result. Ordering and stockholding is simplified too when using the new EJOT product combination because there is no need to source a variety of different concrete screws and stress plates.
It is a lasting solution too thanks to the quality materials used to manufacture both fastener elements. The JBS-R concrete screw is manufactured from case hardened steel and the EcoTek tubewasher is formed from high quality polyamide plastic to stand the test of time.
How installation works:
Tapered insulation and membranes are securely attached to the concrete deck in four stages:
1. Drill a 6mm tapping hole through the membrane and insulation and into the concrete deck to a depth of 35mm.
2. Insert the pre-assembled JBS-R concrete screw and EcoTek tubewasher into the hole.
3. Using an extended T30 bit, drive the screw into place achieving a minimum embedment of 30mm.
4. Complete the installation using the EcoTek Adjustment Tool, driving the tubewasher until a secure clamp of the membrane and insulation is achieved.