Soffit Slab

Soffit Slab is an economical mineral wool designed for concrete soffits in locations such as communal areas and car parks where fire resistance, acoustic and thermal performance are critical. Ease of installation and during construction stability combine with cost effectiveness to make this a product of choice for many.


Fire performance

Soffit Slabs have been tested to BS EN 1363-1 to offer fire protection to reinforced concrete soffits. When applied to the soffit using the recommended fixings and pattern, 130 and 140mm thick products, with and without facings, provide 3 hours fire insulation and integrity to a minimum 90mm thick floor slab. 150 and 160mm thicknesses provide 4 hours to a minimum 150mm thick slab.

Thermal performance

Terrawool Soffit Slab has a thermal conductivity (k value) of 0.034 W/mK.

Thermal resistance of un-faced Soffit Slab:

  • 130mm Soffit Slab: 3.82 m²K/W
  • 145mm Soffit Slab: 4.26 m²K/W
  • 160mm Soffit Slab: 4.70 m²K/W

A typical construction comprising of a 150mm concrete floor slab underlined with 130mm thick Soffit Slab would achieve a U-value of 0.25W/m2K. A U-value of 0.20 W/m2K can be achieved using 160mm thick Soffit Slab.

Technical information

Terrawool Soffit Slab achieves a reaction to fire classification of A1 – BS EN 13501-1.


Terrawool Soffit Slabs are chemically inert and compatible with most materials with which they are likely to come into contact in normal building applications

More Information

Contact our team to find out more about MF Brick Slip