Between and Under Joists

Celotex high performance thermal PIR insulation for use between and under joists.

Application image
U-value Calculator
Start your U-value calculation >
Use the calculator

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

Full Statement > Calculator Icon

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

Read more Calculator Icon

To upgrade an older building, Celotex’ between & under joists solution is an ideal option. With this application it is easy to minimise any loss of internal headroom and it provides reliable long term energy savings for buildings.

Application Benefits:

  • No need to remove existing weatherproofing covering
  • Ventilated cold roof construction
  • When using Celotex plasterboard laminates, the solution offers maximum flexibility and installation speed due to the tapered edge of the plasterboard

View Application Datasheet Calculator Icon


Recommended Products

FR5000 (Currently Suspended)
1200 x 2400mm
(Currently Suspended) 50-150mm
0.021 W/mK

Application Image Thumb View Product

GD5000 (Currently Suspended)
0.021 W/mK

Application Image Thumb View Product