Celotex XR4000 - High-Performance PIR Insulation Board

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product brand
Brand: Celotex
Country of Manufacture: United Kingdom
In Stock
Product Code: CEXR
Est. Delivery: 2-3 Working Days
Shipping cost displayed in basket
£51.99 (ex VAT)
£62.39 (incl VAT)


Celotex PIR is a rigid foam board with versatile applications. They can be used to insulate walls, floors and roofs. They are also approved for use in cavity walls. PIR insulation can also be used to insulate campervans! 

With a strong and resilient PIR core and a low K-value, they give a consistent performance for many years. They are also dimensionally stable and the performance of the PIR insulation does not decrease with time. They provide reliable and long term solutions. Celotex PIR also decreases thermal bridging in all applications. These products provide simple solutions to overcome thermal bridges in specific situations.

They have low emissivity foil facings on both sides which serves two purposes. The foil facings of PIR insulation act as a continuous vapour barrier protecting both the insulation plus your walls, roofs etc from moisture. It helps keeps condensation or other moisture-related problems away. It also reflects heat, thus helping to keep the heat inside. 

Celotex XR4000 is a high-performing PIR board from Saint-Gobain with a low K-Value of 0.022 W/mK. The low thermal conductivity of the PIR insulation ensures superior thermal insulation and significant saving all year round.  

Product Specifications: 

Length (mm)

Width (mm)

Thickness (mm)

Lambda-Value (W/m.K)

R-Value (m².K/W)











Key Features:

  • The high compressive strength ( ≥120kPa) of Celotex boards makes them  ideal for moderate load-bearing applications, especially to insulate floors.
  • PIR insulation has a thermal conductivity of 0.022 W/m.K which ensures superior insulation all year long.  Celotex boards help you achieve the target U-value with reduced insulation thickness.
  • Celotex PIR is specifically designed to eliminate thermal bridging.
  • Low emissivity foil facing serves dual purposes - They prevent heat loss by radiation and also protect the PIR insulation and your walls from moisture by acting as a vapour barrier.  
  • PIR is a lightweight board that is easy to handle and install. 
  • Celotex PIR insulation boards have a BRE Green Guide Rating of A meaning it is environment friendly.



Celotex XR4000 can be specified for use in a variety of applications including;

  • Excellent for use as perimeter upstands in concrete floor structures, suspended timber joists, beam and block. 
  • Roof insulation: Celotex PIR is used to insulate between, above and below timer rafters for pitched roof applications and Below and under timber joists, terraces and balconies for flat roof applications. 
  • Wall Insulation: For external wall insulation including solid walls and timber frame walls. PIR insulation is also used to upgrade cavity wall insulation. 
  • Floor insulation: Celotex PIR insulation can also be used to insulate concrete slabs and suspended timber floors. 

Thermal Performance:

  • With a low K-value of 0.022 W/m.K, PIR boards from Celotex, prevent heat loss, no matter what the application is.
  • Celotex PIR also helps meet the building regulations and required U-value with reduced thickness.


  • Celotex XR4000 achieves a BRE Green Guide Rating of A.
  • PIR is sustainable, long-lasting and environmentally friendly.
  • Celotex PIR is manufactured under Environmental Management System – ISO 14001:2015. 
  • Reaction to Fire:
  • Celotex boards have a Euroclass E Reaction to Fire classification, according to BS EN 13501-1.

Certifications and Standards:

  • BBA Approved (Cert no 17/5405, 16/5352) for floors, dry lining, pitched roof and timber frame applications, when installed, used and maintained as set out in the certification. 
  • CE Marked (18.DOPTB4000-01) to BS EN 13165.
  • Celotex has complied with the requirements of Environmental Profile BRE Global Scheme Document SD028 
  • Celotex XR4000 has obtained the BRE Global Certification Mark. Certificate number ENP413.
  • Celotex boards is manufactured under Quality Management Standard – ISO 9001:2015

Other Details:

  • Material: PIR  with Aluminium foil facings on both sides.
  • Water Vapour Resistivity: >150 MNs/g
  • Edge: Square edge.

Average Customer Rating
Overall 5.0

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