IMPORTANT: On 1 September 2017, Celotex took the precautionary measure to temporarily suspend the supply of Celotex FR5000, Celotex CG5000, Celotex CF5000 and Celotex SL5000 while we investigate the results of recent tests (Parts 6 and 7 of British Standard 476). In addition, we have recently identified a compliance issue relating to our calculation and testing of the declared lambda value of products in the 4000 and 5000 ranges and the Crown-Bond and Crown-Fix products within the Crown Flat Roofing range. Due to this issue, the suspension of the 5000 range will continue and now includes the FI5000 and GD5000 products. Materials relating to the 5000 range products are for information only. Please note that all products in the TB4000, GA4000 below 100mm, PL4000 and CW4000 ranges manufactured after 15 December 2017 will be marketed from January as Celotex 3000 with a declared lambda value of 0.023 W/mK.

Please use the link below to read our full statement regarding declared lambda:

Read more

Please use the link below to read our latest statement regarding Class 0:

Read more

Since Late 2014 Celotex has launched several cutting edge products to the market. A prime example of an innovative product launched just recently, would be the Celotex FI5000 flooring Insulation, which offers a whole host of on site benefits for the installer, saving time & money. With every Celotex product launch, we always drive to understand our customers’ needs, investing the time to design insulation products that the market place is driving towards. New concrete soffit liner solution, Celotex SL5000 is another perfect example.

What is concrete soffit liner insulation?

Celotex SL5000 has redefined the approach to insulating concrete soffits.

Not only does SL5000 offer a super low lambda value of 0.021W/mk, which in turn will reduce ceiling heights, it also boasts a 6mm calcium silicate board that provides a finished surface as a decorative finish. The all-in-one system solution saves the installer time and money on site, eliminating the requirement for two separate materials (insulation & finish board) sourced separately and both requiring separate installation.

What is concrete soffit liner insulation?

How do I install Celotex concrete soffit liner insulation?

Standard practice for soffit construction would be to line the underside of the soffit with a high performing insulation then use a mechanically fixed MF ceiling to cover the insulation as the decorative finish.

Celotex SL5000 offers a different approach as the decorative finish is already bonded to the insulation (6mm Calcium Board). Construction factors will determine the recommended soffit liner application, with typically two types of application methods. Direct fix and indirect fix installation. Direct fix installation refers to the fixing of Celotex SL5000 direct in to the concrete whereas indirect fix installation refers to using timber battens as a counter layer between the insulation and the concrete soffit. This type of fixing is recommended when there is the requirement to create line and level due to an uneven nature of a concrete soffit.

Celotex offers full concrete soffit liner installation guidelines as well as fixings advice for both direct and indirect fix application in our specification guide which you can download here. Alternatively, our Celotex Technical Centre (CTC) are experts in all things insulation and would be happy to discuss your project with you. Find out how to contact them here. You can also contact them via email on The CTC are on hand to help you specify the best solutions to meet your insulation requirements.

Fire performance in concrete soffits

Celotex also recognises the importance of fire performance within a concrete soffit liner application. The insulation component of Celotex SL5000 provides a number of fire performance benefits including:

  • A pass to BS 476 Part Part 6:1989 (Fire tests on building materials and structures – method of test for fire propagation for products).
  • A pass to BS 476 Part 22:1987 (fire tests on building materials and structures – methods for determination of the fire resistance of non-load bearing elements of construction).
  • SL5000 is Class 0 fire rated as described by the national Building Regulations.
  • Classification as Class 1 in accordance BS 476 Part 7:1997 (fire tests on building materials and structures method of test to determine the classification of the surface spread of flame of products).

The calcium silicate component to Celotex SL5000 provides the following fire performance benefits:

  • A pass to BS 476 Part 4 (test method for non-combustibility)
  • A pass to BS 476 Part 22:1987 (fire tests on building materials and structures – methods for determination of the fire resistance of non-load bearing elements of construction).

If you would like to find out more about Celotex concrete soffit liner insulation, Celotex SL5000 contact the CTC where you will find a helpful team who can answer your queries.

Follow us on Twitter, LinkedIn or Facebook for more updates.

This product is available now, nationwide.