Installer: Itech Roofworks
Main contractor: Winter Refurbishments
As part of National House Building Council (NHBC) building works the upper roof now includes 800sq m Sarnafil Plus roofing system with a 20 year guarantee. Installed by experienced Hertfordshire based roofing expert, Itech Roofworks and main contractor Winter Refurbishments, the new roof tops the organisation’s Milton Keynes head office.
The work was undertaken after several water ingress issues were identified. NHBC wanted to ensure a full guarantee was included with regard to waterproofing the building which led to Sarnafil being specified, as it comes with a single point guarantee, making it easy to manage whilst giving peace of mind with the backing of Sika, a major worldwide group.
In order to replace the existing roof, a three step process took place that saw contractor Itech Roofworks overlay the existing D100 metal deck with a T-fleece separation layer before mechanically fixing S327-18 EL membrane using the Sarnabar system.
Itech Roofworks installed profiled foam fillers to the existing profiled metal roofs. The existing lightning protection was then removed to enable roofing works to be undertaken.
The existing roof membrane was cut at the perimeter and at all penetrations to alleviate built up stresses, all defective skirting and flashings were removed and the existing roof was cleaned and prepared for the installation of the separation layer. S-Felt T Fleece was loose laid with 100mm laps. Light Grey, S327-18EL Single Ply Roof Membrane was then loose laid in the same direction as the roof deck corrugations and secured using Sarnabars at 5m intervals. These were installed at 90 degrees to the metal deck corrugations with Sarnafil BS-S stainless steel fasteners, ensuring the fasteners had penetrated through the deck by a minimum 15mm.
The Sarnabars were then weathered with 200mm of Sarnafil S327-18EL Light Grey cover strips, heat welded to the main roof membrane on each side of the Sarnabar and a 150mm up-stand was installed around the 11 existing roof lights in preparation for installation of replacement roof lights.
The Sarnabar system was chosen to ensure that disturbance to staff and members of the public was kept to a minimum. It meant the overlaying process could be done without the need for striping the whole roof which minimised water ingress or disruption.
Sika Sarnafil Area Refurbishment Manager, Neil Smith commented on the job: “The finished product looks very good and the client was extremely happy with the outcome. The team at Itech Roofworks and Winter Refurbishments were great to work with and I would definitely recommend them,” he added.
Itech Roofworks’ General Manager, Tony Reynolds was also pleased with the work. “We’re really happy with the overall aesthetics of the project, as from the client, all the way down to Sika Sarnafil, the feedback has been enormously positive.”