Knauf Insulation is pleased to announce that its Polyfoam® ECO Roofboard Extra, (incorporating the Polyfoam Slimline system) has received a British Board of Agrément (BBA) certificate and now offers the lowest design lambda of any inverted roofboard (XPS or EPS) manufactured in the UK.

The BBA is the UK's major authority offering approval and certification services to manufacturers and installers supplying the construction industry.

Knauf Insulation’s Polyfoam ECO Roofboard Extra has undergone rigorous testing and has met all the requirements set out by the BBA under the European Technical Approval Guideline (ETAG) 031.

The design thermal conductivity of the boards (including moisture correction factor) is 0.034 W/mK for thicknesses greater than or equal to 100mm. When calculating the U-value of the inverted roof the design thermal conductivity should always be used as this value reflects the in-situ performance of the product. For warm roofs the declared lambda of 0.033W/mK should be used in the U-value calculation.

When Polyfoam ECO Roofboard Extra is installed on appropriate decks, it can accommodate a range of finishes and applications including gravel ballast layer, paving slabs, green roofs and pedestrian access roofs, such as balconies and roof terraces. When combined with the Polyfoam Slimline membrane system, Polyfoam ECO Roofboard Extra is a durable solution and will maintain its integrity for at least the lifetime of the roof membrane.

James Hulbert, Business Development Manager Polyfoam XPS at Knauf Insulation commented: “We are committed to continuously improving our offer to the inverted roofing market for waterproofing system holders, specifiers and contractors alike; we recognise that it is crucial to our future success and through the developments made in product quality, thickness, and environmental performance we’ve made significant strides in a relatively short space of time. The roofing sector is moving rapidly and this new BBA certificate is another crucial step for us. I’m pleased to say that we will continue to develop our offer beyond this and look to bring additional news to market shortly.”

Polyfoam ECO Roofboard Extra is manufactured with a GWP<5 and is free from CFCs, HCFCs and any other material with ozone depletion potential in their manufacture and content, and represents no known threat to the environment. What’s more, Polyfoam ECO Roofboard Extra is non bio-degradable, 100% recyclable, lightweight and easy to handle and install.