Knauf Insulation’s Polyfoam® Roofboard is being used to put the ‘protect’ into the protected membrane roof system at seven new police stations being built for the Greater Manchester Police Force. Accepted as the optimum method of flat roof construction, protected membrane roofs rely on a durable layer of high-performance insulation to protect the waterproof membrane. Polyfoam® Roofboard is an extruded polystyrene insulation board specifically designed for insulating roofs and is definitely ‘tough enough’ for the job.
Part of a PFI (Private Finance Initiative) project for a total of 17 new stations across the Greater Manchester area, the seven stations have a high-security ‘Custody Suite’ with a reinforced-concrete roof – a case of keeping things in rather than just keeping them out! At these sites, Bradford-based roofing contractor, Paragon Roofing & Asphalte Limited, laid over 7,000m2 of protected membrane roofing consisting of 100mm thick Polyfoam® Roofboard on two layers of BS 988 roofing asphalt on a glass-fibre underlay. A separating membrane was used above and below the insulation material which is surfaced with a combination of paving slabs and gravel.
Sometimes known as ‘inverted’ or ‘upside down’ roofs, protected membrane roofs are accepted as being the optimum method of flat roof construction. The layer of insulation protects the roof’s waterproof membrane from temperature variations, mechanical damage and UV degradation – all factors that can threaten its watertight integrity. Although the build-cost is usually slightly more expensive, designers and owners argue that this is more than compensated for by the design benefits and low whole-life cost of the roof.
Apart from the technical and maintenance benefits, protected membrane roofs also offer another attractive benefit: flexibility of use. Providing the insulation material has sufficient compressive strength, the roof can also be used as a balcony, a patio, a terrace, a garden or a car park (or even a heli-pad for that quick get-away!).
Polyfoam® Roofboard is a high-performance, extruded polystyrene insulation board ideally suited for thermally insulating protected membrane roofs. Made from Polyfoam® extruded polystyrene, its high compressive strength and total moisture resistance provide an outstanding structural insulation solution and one that’s definitely ‘tough enough’ for the job.
Three grades of board are available – Standard, Extra and Super – giving designers the opportunity to specify the optimum product to meet the intended use of the roof. The grades cover everything from the light loads associated with occasional pedestrian maintenance traffic, through the demands of increasingly popular green roofs to the high loads imposed by vehicle movement. The boards come in one manageable size – 1250mm x 600mm – are available in a range of thicknesses, have interlocking, rebated edges and are lightweight, easy to store, handle and install.
Knauf Insulation recently launched a new innovation for protected membrane roof construction: the Polyfoam® Slimline System. The system uses Polyfoam® Roofboard and a special separation membrane to successfully reduce the effect of moisture cooling on the roof – doing so allows both the insulation layer and the layer of slabs or ballast to be reduced in thickness. As a result, the building’s construction can be lighter and, consequently, less expensive, without compromising the flexibility of use benefits provided by protected membrane roof construction.
More information about Knauf Insulation’s products can be found on their website at www.knaufinsulation.co.uk or by calling 08700 668 660. Please quote PR 226 04.
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