As part of National House Building Council (NHBC), Milton Keynes head office building works, the upper roof now includes 800sq m Sarnafil Plus roofing system with a 20 year guarantee. 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 by Sika Sarnafil. 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. Light Grey, S327-18EL Single Ply Roof Membrane was 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.