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    Flat Roofs

    Product Type:

      Extruded Polystyrene (XPS)

    Market Sector:


    Polyfoam Roofboard Extra

    Product Description:

    For inverted and green roofs


    The declared thermal conductivity of POLYFOAM Roofboard Extra is 0.033W/mK.

    The design thermal conductivity in including moisture correction factor, of the boards, is 0.034W/mK for thicknesses ≥ 100mm. For thicknesses under 100mm it is 0.035W/mK



    POLYFOAM Roofboard Extra is a rigid extruded polystyrene (XPS) board with a Global Warming Potential (GWP) of less than 5 and achieves a BRE Certified Green Guide Rating of A.

    POLYFOAM Roofboard Extra is a lightweight, lap jointed board with high compressive strength.

    ‎POLYFOAM Slimline Zero Membrane is a high performance, thermally bonded tri-laminate of polypropylene; spunbonded (outer layers) and microporous (inner layer).


    • Excellent thermal performance
    • 15mm lap joint
    • High compressive strength
    • Highly resistant to water absorption
    • Able to resist repeated freeze/thaw cycles
    • Lightweight and easy to install
    • Tough and durable, not easily damaged
    • Dimensionally stable
    • Thermal performance of an inverted roof is improved when used in conjunction with ‎POLYFOAM Slimline Zero Membrane


    POLYFOAM Roofboard Extra is used for the thermal insulation of a wide variety of flat roofs including:

    • in an inverted roof below ballast or paving slabs
    • in a green/garden roof