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A1 non-combustible, BBA certified fibre cement building board

RCM Y-wall is a high-quality flexible calcium silicate based fibre cement building board with additives, perfect for use as a fire rated sheathing board.  Offering excellent fire properties as well as high levels of dimensional stability Y-wall is an exceptional board for use in multiple applications.

Y-wall is used primarily as a fire rated sheathing board or building board. Used extensively on both steel frame and timber frame structures, Y-wall is used behind all types of facade solutions, as well in ceilings offering a non-combustible classification.

Y-wall is ideal for modular construction methods.


  • Fire rated to EN 13501-1 class A1
  • BBA approved
  • Flexible and strong
  • Excellent water resistance
  • Easy to use
  • High levels of dimensional stability
  • Integrates with other RCM products

Standard board sizes

2400 x 1200mm (6mm, 9mm, 12mm and 15mm)

Other board sizes are available.


RCM Y-wall can be cut, drilled and nailed using conventional hand tools; offering many of the properties of timber.

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.

Key applications

  • Fire rated sheathing board
  • Ceilings
  • Partition walling
  • OEM applications for improved strength and density
  • Recommended for buildings above 18m

Suitable for the following construction types

  • Lightweight Steel Frame
  • Timber Frame
  • Modular / Offsite

Technical Data

  • 1200 kg/m3
  • 12 N/mm2
  • 4000 N/mm2
  • ≤0.30 W/mk
  • ≤9%
  • ≤0.25%
  • BS EN 13501-1 Class A1 Non-Combustible
  • Highly Resistant
  • Front Face - Smooth
  • Back Face - Textured
  • 30 years
  • 2400 x x 1200mm
  • 6 9 12 15
  • 7.3 11.1 14.6 18.2
  • 24 29 31 33
    • Length
    • Width
    • Thickness
    • Fire Reaction Tests
      BS EN 13501-1 Class A1
    • BS EN ISO 1716:2010
    • BS EN ISO 1182:2010
    • BS 476 Part 4
    • BS 476 part 21 and BS 476 part 22 fire rated through wall solutions
    • Physical Properties
      BS EN ISO 12467
    • BS EN 594 Category 1
    • BS EN ISO 1015-11
    • BS EN ISO 1062-1
    • Steel Frame
      4.8mm x 38mm Wing tip self drilling fixing
    • Timber Frame
      4.2mm x 42mm Climaseal self drilling fixing


Case Studies

01 . 7
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