70mm SOPRATHERM CW4000 (previously Celotex) - PIR Cavity Wall Insulation Board - 1200mm x 450mm - pack of 8
70mm SOPRATHERM CW4000 (previously Celotex) - PIR Cavity Wall Insulation Board - 1200mm x 450mm - pack of 8
- Product Code: A1-7036
- Delivery Time: 2 - 3 working days
- Brand: Soprema (Tech. support: 03300580668)
- Model: 1200mm x 450mm - 4.32m2
Our ratings on 18-09-2026:

4.8 out of 5
70mm SOPRATHERM CW4000 (previously Celotex) - PIR Cavity Wall Insulation Board - 1200mm x 450mm - pack of 8
Length: 1200mm
Width: 450mm
Thickness: 70mm
Pack Quantity: 8
Board Coverage: 0.54m2
Pack Coverage: 4.32m2
Thermal Conductivity: 0.022W/mK
R-Value: 3.15m2K/W
Compressive Strength: 120kPa
Fire Rating (Reaction to Fire): F
Surface Spread of Flame: Class 1
70mm SOPRATHERM CW4000 (previously Celotex CW4000) is a high-performance, rigid PIR insulation board specifically engineered for partial-fill masonry cavity walls. It features low-emissivity foil facings on both sides to enhance thermal performance within the cavity air space.
CHARACTERISTICS
- With a thermal conductivity of 0.022 W/mK, it allows for very low U-values with a thinner profile than traditional mineral wool, preserving more of the building's footprint.
- The foil facings are designed to reflect radiant heat back into the building. When installed with a clear residual air gap, these facings significantly improve the thermal resistance of the cavity.
- The boards are sized at 1200mm x 450mm to fit perfectly between standard wall tie spacings, which drastically reduces the need for on-site cutting and minimizes waste.
- The closed-cell structure of the PIR foam is naturally water-resistant. It will not absorb water if the cavity becomes damp, ensuring the insulation maintains its performance over the life of the building.
- Despite its strength, the board is light and easy to handle, making it simple to secure with standard cavity tie clips.
APPLICATION
- Partial-Fill Cavity Walls: The primary application. It is installed against the inner leaf of a masonry wall, leaving a residual air gap (usually 50 mm) between the insulation and the outer leaf.
- New Build & Refurbishment: Suitable for both new masonry constructions and the thermal upgrading of existing cavity walls.
CERTIFICATION
- BBA approved – certificate 24/7312 (Partial Fill Cavity Walls)
- Soprema operates independently monitored Quality and Environment Assurance Systems in line with EN ISO 9001 and EN ISO 14001.
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