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A High Performance, Mineral Coated, Glass Faced Xtratherm Roof Insulation


Xtratherm roof insulation provides the perfect flat roofing solutions for a wide array of roofing projects. Xtratherm FR/MG is is a specialised Polyisocyanurate (PIR) product with mineral coated glass facers that offers certified thermal conductivity as low as 0.024W/mK. Within the Xtratherm Roof Insulation range, FR MG is the ideal high performance insulation board for single ply fully adhered membranes, singly ply waterproofing systems and partially bonded built-up felt systems.

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products benefits:

Suited to single ply fully adhered & partially bonded built-up felt systems

Offers high performance and thermal conductivity levels as low as 0.024W/mK

Coated with mineral glass facers

The ideal insulation solution for flat roof projects

Tech info:

  • Density


  • Compressive Strength

    >150kPa @ 10% Compression

  • Thermal Conductivity

    0.024 - 0.027 W/mK

  • U-value (80mm)


  • U-value (90mm)


  • U-value (100mm)


  • U-value (120mm)


  • U-value (140mm)


  • Length (mm) - UK; Ireland

    1200; 1200

  • Width (mm) - UK; Ireland

    600; 1200

  • Full Information:

    Check out the full
    datasheet available in
    the Downloads section!

More Info

Vapour Control Layer
A continuous approved vapour control layer should be used below the insulation. (Unless over a sealed metal deck system). For mechanically fixed boards, a minimum vapour control layer of a 1000 gauge polyethene layer lapped and sealed with double-sided tape should be used below the insulation. At vertical upstands and penetrations, the VCL should be turned up and sealed to encapsulate the insulation layer prior to the roof finish being completed. (A comprehensive U-value calculation and condensation risk analysis should be carried out for all projects).

Bonding Boards to the Vapour Control Layer
The minimum vapour control layer should consist of a 3B type felt to BS747 Reinforced bitumen sheets for roofing. Specification or BS8747. Reinforced bitumen membranes (RBMs) for roofing. Guide to selection and specification. Other proprietary systems may be used subject to approval. Where the vapour control layer is to be bonded separately, sufficient adhesion to the substrate should be made to ensure correct resistance to wind uplift. Contact the system manufacturer for details.

Membrane Systems
Please contact Xtratherm Technical Support for advice on membrane and adhesive system compatibility. Technical guidance from the appropriate waterproofing manufacturer should be sought.

Xtratherm FR/MG boards are suitable for use on roof decks that are subject to maintenance traffic. Walkways should be provided on roofs requiring regular pedestrian access. When the roof is complete, protective boarding should be laid if additional site work is to be carried out.