Celotex XR4000 insulation board
Celotex XR4000 is a high performance, easy to install polyisocyanurate (PIR) insulation board featuring a low emissivity foil facing. Available in thicknesses from 110mm to 200mm, it can be considered for roof, wall and floor applications.

U-value Calculator
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- Ground Floor - Concrete Slab
- Ground Floor - Suspended Timber Joist
- Ground Floor - Beam and Block
- Ground Floor - Upgrading Existing Concrete Slab
- External Wall - Timber Frame Sheathing
- External Wall - Between Timber Frame Studs
- Pitched Roof - Over Timber Rafters
- Pitched Roof - Sarking
- Pitched Roof - Between Timber Rafters
- Pitched Roof - Loft insulation - Between and Over Timber joists
- Flat Roof - Balconies and Terraces Over Timber Joists
- Flat Roof - Between Timber Joists
Product Features
- Lightweight 2400 x 1200mm boards
- Low emissivity foil facing
- Achieves a BRE Green Guide A rating
- BBA approved – certificates 16/5352, 17/5405
Product Properties
- Board / Roll size: Width 1200mm, Length 2400mm
- Thickness : 110-200mm
- Material: PIR
Product Performance
- Lambda: 0.022 W/m.K
- Reaction to Fire: Reaction to Fire: Euroclass E Reaction to Fire classification, according to EN 13501-1
Product Benefits
- Excellent thermal performance - decreasing the thickness of insulation required to hit the required U-value, optimising space in the construction design and helping to reduce the heating and cooling costs within the building
- Low emissivity foil facing provides improved thermal performance in sealed cavity air spaces, improving the achievable U-value
- Easy to install – lightweight boards are straightforward to handle fit and transport
- BBA certification - third-party verification that the product has been assessed for its defined applications and is compliant with the relevant Building Regulations.
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Applications: Click here to discover applications
- Roofs - Pitched Roof - Sarking
- Roofs - Pitched Roof - Between and Over Rafters
- Roofs - Pitched Roof - Between Rafters
- Roofs - Pitched Roof - Between and Under Rafters
- Roofs - Pitched Roof - Loft Insulation
- Roofs - Flat roof - Balconies and Terraces
- Roofs - Flat roof - Between and Under Joists
- Walls - External Walls - Timber Frame
- Floors - Ground Floors - Beam and Block
- Floors - Ground Floors - Concrete Slab
- Floors - Ground Floors - Suspended Timber
- Upgrading - Concrete Slab Floors