Celotex CW4000 Cavity Wall Insulation Boards
(3 Products)Celotex CW4000 is a high-performance PIR insulation board engineered for partial-fill cavity wall applications in masonry construction. Designed to be installed against the inner leaf, it maintains a residual air gap that enhances thermal efficiency while facilitating moisture management. With exceptional thermal conductivity (0.022 W/mK) and a closed-cell structure for superior moisture resistance, CW4000 provides a robust solution for improving building energy efficiency, regulatory compliance, and long-term durability in both new-build and retrofit projects.
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What Is CW4000?
Celotex CW4000 is a high-performance PIR insulation board designed for partial-fill cavity wall applications. It is installed against the inner leaf of a masonry cavity wall, leaving a residual air gap between the insulation and the external leaf. This gap allows any moisture that penetrates the outer brickwork to drain away, reducing the risk of damp and water ingress while still delivering exceptional thermal efficiency.
With a low thermal conductivity of 0.022 W/mK, CW4000 delivers outstanding thermal performance, helping to minimise heat loss. Its closed-cell structure provides excellent moisture resistance, mitigating the risk of water ingress from the external leaf while maintaining breathability within the cavity.
In terms of performance, Celotex CW4000 offers a range of physical properties that make it an optimal choice for cavity wall insulation. It has a compressive strength of ≥120 kPa (as per BS EN 826), ensuring it maintains its shape and performance under load. It also boasts excellent dimensional stability and water vapour resistance, contributing to long-term durability and reducing the risk of moisture-related issues, such as mould or damp. The product complies with the CE marking and meets the standards set out in BS EN 13165.
Designed to integrate seamlessly with standard wall tie spacings, CW4000 simplifies installation and ensures consistent insulation coverage. Compliant with Part L of the Building Regulations, Celotex CW4000 is a preferred choice for architects, specifiers, and contractors looking for a high-performance insulation solution that meets modern efficiency standards.
What Does CW Stand For?
The "CW" in Celotex CW4000 stands for "Cavity Wall," highlighting its specific design for partial-fill cavity wall insulation. This designation reflects its intended use in masonry cavity walls, where it provides excellent thermal efficiency while allowing for a residual air gap to manage moisture and prevent damp issues.
Applications
- Walls - External Wall Insulation - Partial Fill Masonry Cavity Walls
Please note - Celotex CW4000 is not suitable for use in external walls of buildings over 18 metres in height (England and Wales) or 11 metres in height (Scotland).
Changes in Building Regulations have restricted the use of combustible insulation in structures of specified heights and above.
Benefits
- High-performance PIR insulation board designed specifically for use in partial fill cavity wall (CW) insulation applications.
- Boasts a low thermal conductivity of 0.022 W/mK, reducing heat loss and improving energy efficiency in masonry cavity walls.
- Narrow profile allows for effective insulation while maintaining a clear residual cavity, preventing moisture transfer.
- Conveniently sized to fit between wall ties in masonry cavity walls, making installation quick and efficient.
- Faced with low-emissivity aluminium foil, enhancing thermal performance by reflecting heat.
- Lightweight, rigid, and easy to install, making it ideal for both new build and refurbishment projects.
- Moisture-resistant closed-cell structure prevents water absorption, ensuring long-term durability and insulation integrity.
- Manufactured to meet UK Building Regulations, providing a reliable and effective solution for cavity wall insulation.
CW4000 Thicknesses
Frequently Asked Celotex CW4000 Questions
Can Celotex CW4000 be Used in Full-Fill Cavity Wall Applications?
No, CW4000 is specifically designed for partial-fill cavity walls. A residual air gap must be maintained between the insulation and the external leaf to allow for moisture drainage and maintain performance. For full-fill applications, alternative insulation products like mineral wool batts may be more suitable.
Does Celotex CW4000 Require a Vapour Control Layer?
No, CW4000 has built-in moisture resistance due to its closed-cell PIR structure and foil facings, reducing the need for an additional vapour control layer. However, proper detailing and airtight construction are essential to prevent interstitial condensation.
Can Celotex CW4000 be Cut On-Site?
Yes, CW4000 is easy to cut using a fine-toothed saw or a sharp knife. Cutting should be done in a well-ventilated area, and appropriate PPE, such as a dust mask and gloves, is recommended.
How Should Celotex CW4000 Be Installed with Wall Ties?
Wall ties should be installed as per the manufacturer’s guidelines, ensuring they are positioned correctly to support both the insulation boards and the outer masonry leaf. Retaining clips should be used to securely hold the boards in place.
Is Celotex CW4000 Fire-Rated?
Celotex CW4000 has a Euroclass E fire rating, meaning it is combustible and should be used in accordance with relevant building regulations, particularly in high-rise or fire-sensitive applications. Additional fire protection measures, such as masonry barriers, may be required.
Can Celotex CW4000 be Installed in Refurbishment Projects?
Yes, CW4000 is suitable for both new-build and retrofit projects, provided there is a suitable cavity wall construction in place and adequate residual air space can be maintained.
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