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Celotex XR4120 General Purpose PIR Insulation Board - 2400 X 1200 X 120mm

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£66.92 Incl. VAT
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Celotex XR4120 is a highly versatile multi-purpose insulation board ideal for various applications including pitched roofs, flat roofs, solid floors and masonry walls and steel framed and timber framed systems. Made of sturdy polyisocyanurate (PIR), it's easy to handle, cut and shape. This convenient high-performance insulation board has excellent thermal performance and an impressive thermal conductivity of 0.022 W/m.K. Knowing that, you won't be surprised to learn that it easily meets the required U-value while also being thinner than most similar products on the market.

But wait - there's more! The low emissivity foil facing improves thermal performance in sealed cavity air spaces and boosts the potential U-value. The XR4120 is produced to the highest manufacturing standards and has a BBA (British Board of Agrement) certificate as fit for use in defined roof, wall and floor applications when installed, used and maintained according to the guidelines. Additionally, the board has a BRE (Building Research Establishment) Green Guide Rating of A, which will assist you in improving your environmental performance. Altogether, this PIR insulation board will provide reliable long-term energy savings for your home.

Features & Benefits: Celotex XR4120 General Purpose PIR Insulation Board - 2400 X 1200 X 120mm

  • Top-quality PIR insulation board
  • Excellent thermal performance
  • Lightweight, quick & easy to install
  • Suitable for roof, wall and floor applications
  • Low emissivity foil facings for improved thermal insulation performance in cavity air spaces
  • BRE Green Guide Rating of A
  • BBA certified

Product Specification

  • Length: 2400mm
  • Width: 1200mm
  • Thickness: 120mm
  • Coverage: 2.88m2
  • R-Value: 5.45m2K/W
  • Maximum weight: 4.93kg/m2
  • Thermal conductivity: 0.022W/m.K, according to BS EN 13165 for factory made rigid polyurethane foam (PU) product
  • Compressive strength (kPa): CS(10\Y)140
  • Spread of flame: Euroclass E Reaction to Fire classification, according to BS EN 13501-1. Products with this level of classification are not provided with a rating for smoke emission.


Length 2400mm Thickness 120mm Width 1200mm


Edging Square Edge Facing Foil Product Type Board Material PIR

Questions & Answers


Can this product be used as a warm deck with 6mm ply fixed from above with slab nails into the joists .???


It can be used in a warm roof/deck application, but would suggest a thicker ply (12mm) to overlay. - https://www.insulationsuperstore.co.uk/help-and-advice/project-guides/insulation/insulating-a-flat-roof/


Is the silver foil a vapour barrier?


When used in conjunction with aluminium foil tape, you can create a pseudo air tight seal with your insulation layer, however it is not a complete vapour barrier and so having another vapour control layer in place would be best. 


Is this product approved for use in flat roofs?


Yes, Celotex TB400, GA400 and XR400 can be used in a flat roof. 

Have a question about this product?


5 / 5 8 reviews
Andrzej Szarko
15th May
Good quality alternatives
20th March
Came as a 4 pack, shrinks wrapped so all in good condition
17th May 2021
Good quality
R Welch, Edinburgh
18th April 2021
Almost as thick as I am !
Colin t
21st March 2021
Just the thickness needed, good product
22nd March 2020
Good quality easy to use
Ross Gorbert
21st March 2020
Was the right thickness and insulates
1st January 2020
excellent service
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Celotex XR4120 General Purpose PIR Insulation Board - 2400 X 1200 X 120mm

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