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Soffit Insulation

ProTherm RockFace A2 SL Soffit Board


ProTherm RockFace A2 SL is a non-combustible, fire tested Soffit Insulation Board designed to insulate semi exposed concrete soffits. Manufactured with non-combustible Stonewool factory laminated to a 6mm thick weather resistant high impact calcium silicate fibre cement facing board, ProTherm RockFace A2 will not develop smoke or promote flame spread, even when directly exposed to fire. It also repels and drains away water completely drying out while maintaining its original physical properties. The calcium silicate fibre cement facing board is BBA certificated (BBA certificate No. 21/5983) and independently tested and classified as Category A for external use in accordance with EN 12467:2012. Available in a range of thicknesses, see declared performance table for available thickness.

Available in a range of thicknesses, see declared performance table for available thickness. RockFace A2 SL has a Zero Ozone Depletion Potential (ODP), a Global Warming Potential (GWP). Certificates ISO 9001@2008 Quality Management System,
ISO 14001 :2004 Environmental Management System, EPD as per ISO 14025 and EN 15804. 

For a comprehensive NBS J31 specification contact Radmat Building Products.


RockFace A2 SL can be mechanically fastened to:

• The underside of a profiled steel, flat steel or concrete soffit on buildings over 18m providing the structure meets the performance requirements of BS9991:2015, Approved Documents B and BS 8759:2020.


RockFace A2 SL boards should be fixed using Ejot DDS fixings with the Ejot DDT70 washer or similar, direct to the concrete soffit, refer to the diagram below for the recommend number and positioning for each board size. Fasteners and washers should be installed so as to prevent RockFace A2 SL panels becoming dislodged by wind or maintenance work.

When fixing directly to a steel or concrete soffit RockFace A2 SL boards fasteners should be positioned a minimum of 100mm in from the edges of the board, at 300mm centres across the width and at 500mm centres along the length (achieving 7 fasteners per board).  The minimum penetration of the fasteners into the substrate must comply with the fastener manufacturer recommendations. A space of 0.5 to 2mm should be left between each board to allow for thermal expansion.

At perimeters the RockFace A2 SL must either abut a vertical surface (a space of 0.5 to 2mm should be left between each board to allow for thermal expansion) or be closed off with a suitable cover flashing.

Description  Value
Board Width 1000mm
Board Length 1200mm*
Board Thickness (inc facing) 26mm + (increments of 10mm)** 
Board Weight kg RF26, 11.4/RF56, 18/RF116, 26.5/RF136, 29.5
Core Stonewool non-combustible insulation
Thermal Conductivity Core 0.038 W/mK
Fire Performance Euroclass A2-s1,d0 WarringtonFire

*smaller boards 1000mm x 600mm are available for thicknesses above 100mm


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