Flat roofing fastening solutions from SFS, including its isoweld® 3000 system, have played a key role in delivering a high quality building – the University of Chester’s Energy Centre, a nationally significant facility which will aid the development of cost effective and environmentally responsible sources of energy.
The Energy Centre is located on the University’s Thornton Science Park. The refurbishment project undertaken by Willmott Dixon posed particular challenges in respect of the flat roof, which consisted of a solid concrete deck, followed by screed laid to falls, a thin dense concrete layer and three bituminous membrane layers.
The new roof specification required the application of new insulation to upgrade the thermal performance and a new single ply waterproofing membrane. Due to the location of this project and the presence of existing bonded layers, adhesive application was ruled out at an early stage and a mechanically fastened solution was sought.
Initial pull-out tests confirmed that fixing was required through the existing screed and direct into the concrete deck. The screed layer varied in depth between 190mm to 290mm, and when including the new 120mm insulation board, a total build-up of between 310mm and 410mm resulted. With the roof’s high exposure rating and dimensions, wind load calculations indicated that only corner and perimeter zones should be used, which demanded a high density of fasteners in these areas.
Working with Range Roofing, the solutions provided by SFS included its TIA adjustable fastener in combination with the isoweld® 3000 heat induction welding system. This fastener system included specially coated isoweld® stress plates combined with 230mm and 300mm FI-R-20 sleeves and the 150mm long TIA fastener. These were installed through the insulation and screed layers and were mechanically fastened into the concrete substrate.
The fasteners were applied through the insulation boards in a field fix grid pattern followed by the Protan SE single ply waterproofing membrane, which was then installed using the specialist isoweld® 3000 system, welding the membrane directly onto the isoweld® stress plates. This provided an extremely secure fix, without having to “duplicate” fasteners, and the associated drilling, and without the need to penetrate the waterproof membrane as would be necessary on seam fix systems.
Jamie Dixon, Site Supervisor at Range Roofing commented: “The innovative SFS adjustable TIA fasteners combined with the FI-R-20 sleeves reduced the amount of drilling into concrete by 40%, requiring pilot holes just 35mm deep into the concrete deck, allowing for 20mm fastener embedment for the whole scheme. Just one TIA fastener and two FI-R-20 sleeves were required for the majority of this 1,000m2 project, which considerably simplified the installation procedure. The isoweld® 3000 machine was easy to use, and the in-built safety functions ensured that welding would only occur when the inductor was over the stress plate.”
Drilling was simplified by using SDS drills to core out the screed and bitumen layers, and the pilot holes for the TIA fasteners were drilled using SFS ZVK stop drills combined with the ZAK extension bars. This ensured that the pilot holes were of the correct depth and location for the fastener installation.
Steve Holford, Business Development Manager / UK Sales Support Manager of Protan added: “Protan provided a high performance single ply waterproofing membrane solution for this project which was enhanced by the use of SFS’s isoweld® 3000 system. The field fix application enabled the use of wider membrane for the complete project, thereby significantly reducing the seam welding requirement and number of fasteners required.”
To find out more about SFS solutions for flat roofing and download the 2018 Flat Roofing Catalogue, visit www.sfsintec.co.uk.