Derbigum Flat Roof Membranes

  • What does APP stand for?

    Atactic Polypropylene. Derbigum is manufactured from the highest quality APP, known as TPO (Thermoplastic Polyolefin).

  • What is the melt/softening point of APP modified bitumen?

    Approximately 140°C

  • What is the % of APP/Straight run bitumen in Derbigum?

    Approximately 30%/70%

  • What are the two main benefits of APP?

    High melt point & UV resistance, resulting in extended life and low maintenance costs.

  • What warranties are available on Derbigum systems?

    12, 15 and 20 years, covering latent product defect and workmanship. Extended warranties and/or enhanced terms are available for selected projects upon application.

  • Who can install Derbigum?

    A network of Derbigum registered Contractors, covering the whole of the UK and Eire.

  • Does Derbigum have an Agrément Certificate?

  • Does Derbigum carry a CE mark?

    Yes – all Derbigum cap sheets and underlays carry the CE mark.

  • As stated in the BBA certificate, in what year was Derbigum first used?


  • According to the BBA, what is the minimum life expectancy of Derbigum?

    In excess of 30 years.

  • What is the recommended reinforcement for base layers for use with Derbigum Torch?

    Glass fibre - remain stable under heat of torched application. Never use lightweight polyester reinforced base layers.

  • What is the typical cold bend temperature for Derbigum?


  • Has Derbigum ever been used within the Arctic circle?

    Yes, in Spitzbergen, where winter temperatures can reach minus 50°C

  • Why is the upper surface of Derbigum Black talced?

    Prevents sticking in transit/storage.

  • What is the striped effect on the surface of Derbigum Black caused by?

    It is the glass reinforcement which is just underneath the bitumen surface of the product. The glass fibre gives the product stability in hot conditions, prevents shrinkage, and reflects heat.

  • What is the finish to the underside of Derbigum Torch, Rapido, Cold, and Mech Fixed?


  • What colours of mineral finish is Derbigum available in?

    Standard mineral colours are light grey, dark grey and charcoal. Other colours may be available to order, subject to minimum production quantities – contact Alumasc for further details.

  • What are the two main benefits of the glass fibre incorporated into Derbigum?

    Stability under torching/reflection of heat in use.

  • What are the two main benefits of the polyester incorporated in Derbigum?

    Tensile strength/resistance to puncture.

  • What are the typical approximate fixing rates of Derbigum Systems?

    Rapido 200+ m²/person/day.
    Cold 130 m²/person/day.
    Torch 100 m²/person/day.

  • What propane gas pressure should be used when torching Derbigum?

    4 bar (60 psi). Never use any gas other than propane.

  • How many million square metres of Derbigum have been laid worldwide?

    600 million m².

  • How many million square metres of Derbigum have been laid in the UK?

    18 million m².

  • What is the fire rating of Derbigum Mineral/Derbigum with stone chippings?

    F.AA to BS476 pt3 1958 (equates to EN1187/4)

  • What is the fire rating of Derbigum Black?

    F.AC to BS476 pt3 1958 (equates to EN1187/4)

  • Is Derbigum Factory Mutual approved?

    Yes – Derbigum (FM blend) is specially formulated to meet Factory Mutual requirements and is available to special order.

  • Can Derbigum meet the latest European fire standards?

    Yes - a special formulation is available which meets all the relevant European Standards (ENV 1187:2002 tests standard 1

Not found what you

Our cookies are switched ON. More information about how cookies are used on our website (including how to manage them) can be found in our Privacy Policy & Cookies. *We will use a cookie to remember your preference.