High performance dimensionally stable render carrier board

RCM Renderflex is a high-performance cellulose fibre cement building board, offering excellent strength, weathering and stability properties when used in conjunction with polymer renders.

Renderflex has been specially formulated to achieve a strong key between polymer basecoats and top coats. The unique board structure offers a high tensile strength (ILB) essential for long term durability, whilst being developed to minimise board movement reducing any stress being applied to the render system.

  • EN 13501-1 class A2-s1, d0

  • 2400 x 1200mm (6mm, 9mm and 12mm)

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  • Fire rated to EN 13501-1 class A2-s1, d0
  • BBA approved
  • High dimensional stability
  • Excellent weathering properties prior to render application
  • High impact resistance
  • Maintains minimum board movement
  • Reduced stress on rendered finish
  • Integrates with other RCM products

Key applications

  • Render carrier board
  • For use with polymer renders
  • Internal and external applications
  • Fascia’s and soffit liner


RCM Renderflex can be drilled, screwed and nailed with conventional hand tools.

For cutting the product in any volume, we recommend the use of an RCM poly crystalline diamond Dart Blade to avoid excessive wear on other blades. Alternatively, RCM offer a complete fabrication service, please contact our technical department for details or visit our fabrication and design page here.

Suitable for the Following Construction Types

  • Lightweight Steel Frame

  • Timber Frame

  • Modular / Offsite

Technical Data

  • Nominal Density

    1380 kg/m3

  • Bending Strength

    ((Modulus of Rupture))

    17 N/mm2

  • Modulus of Elasticity (MoE)

    ((Oven Dry))

    9210 N/mm2

  • Thermal Conductivity

    0.12 W/mk

  • Moisture Content


  • Reaction to Fire

    BS EN 13501-1 Class A2 Limited Combustability

  • Biological Resistance

    Highly Resistant

  • Surface Condition

    • Front Face


    • Back Face


  • Durability


    30 years

  • Standard Board Sizes

    • Dimensions

      2400 x 1200mm

    • Thickness

      6mm 9mnm 12mm

  • Nominal Mass of Product


    8.3 12.4 16.6

  • Dimensional Tolerance

    • Length


    • Width


    • Thickness


  • Product Testing and Certification

    • Fire Reaction Tests

      BS EN 13501-1 Class A2 Limited combustibility

      BS EN ISO 1716:2010

      BS EN ISO 1182:2010

      BS EN 13823:2002

      BS 476 Parts 6 & 7

    • Physical Properties

      BS EN ISO 12467:2012

  • Recommended Fixings

    • Steel Frame

      4.8mm x 38mm Wing tip self drilling fixing

    • Timber Frame

      4.2mm x 42mm Climaseal self drilling fixing


RCM Renderflex is used as a Render carrier board for most polymer modified thin coat render systems.

RCM Renderflex can be used as an exterior brick and stone slip carrier board.

RCM Renderflex has one smooth face and one textured face, the smooth face should be fixed outermost.

RCM Renderflex has a rating of A2 to EN13501-1 this is a reaction to fire classification and should not be confused with fire resistance.

No, RCM Renderflex cannot be left permanently exposed.

RCM Renderflex edge distance is 12mm except at the board corners where fixings should be moved up or down to achieve 50mm. Fixings should be fixed using a maximum 600mm x 300mm grid pattern.

  • 27 No. fixings per 2400mm x 1200mm sheet when fixed in a vertical orientation.
  • 25 No. fixings per 2400mm x 1200mm sheet when fixed in a horizontal orientation.
  • For fixing into SFS framing 4.8mm x 38mm self-drilling wingtip fixings suitably treated against corrosion should be used.
  • For fixing into Timber framing 4.2mm x 42mm self-drilling fixings suitably treated against corrosion should be used.

RCM can supply Poly Crystalline Diamond (PCD) blades suitable for cutting RCM Renderflex in a range of diameter and bore sizes, please contact RCM Technical department for further information.

Langdon Case Study

In January 2008, the Devon Partnership NHS Foundation Trust approved plans for a major redevelopment of the Langdon Hospital site based in Dawlish.

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  • Renderflex used in a timber or steel build-up


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    Renderflex Key Features

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    Renderflex Case Study

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