140mm Unilin XT/CF Thin-R Plus CavityFill

Unilin XT/CF 140mm is a high-performance PIR insulation board designed for full-fill cavity wall applications in new masonry construction. Part of the Thin-R Plus range, CavityFill combines a low thermal conductivity of 0.021 W/mK with a textured foil facing on both sides to provide an efficient layer of thermal insulation within external cavity walls.

The 140mm board is designed to leave a 10mm residual cavity, helping provide protection against wind-driven rain while maintaining effective thermal performance. CavityFill can be used in traditional cavity wall constructions and is designed to help achieve low wall U-values when correctly specified as part of the overall wall build-up. Unilin's published calculations show U-values as low as 0.17 W/m²K for a 140mm XT/CF board, depending on the wall construction and materials used.

140mm Unilin XT/CF Product Details

1. Product: Unilin XT/CF Thin-R Plus CavityFill
2. Thickness: 140mm
3. Board dimensions: 1200mm × 450mm
4. Insulation type: Enhanced PIR
5. Application: Full-fill cavity wall insulation
6. Thermal conductivity: 0.021 W/mK
7. Typical R-value: 5.46 m²K/W
8. Compressive strength: 120 kPa (CS 10Y)
9. Facing: Textured foil on both sides
10. Residual cavity: 10mm
11. Fire classification: Euroclass E
12. Board coverage: 0.54m²
13. Pack quantity: 3 boards
14. Pack coverage: 1.62m²

The manufacturer's current specification confirms the 140mm thickness, 1200 × 450mm dimensions, 0.021 W/mK thermal conductivity, 120 kPa compressive strength and Euroclass E reaction-to-fire classification.

Key Benefits of 140mm CavityFill

High thermal efficiency

With a thermal conductivity of 0.021 W/mK, Unilin XT/CF provides strong thermal performance from a relatively slim insulation thickness, making it suitable for cavity wall designs where space and thermal requirements need to be balanced.

Full-fill cavity wall application

The 140mm XT/CF board is designed for use as full-fill insulation in external masonry cavity walls while retaining a 10mm residual cavity.

Protection against wind-driven rain

Maintaining the specified residual cavity helps reduce the risk of wind-driven rain reaching the inner leaf of the wall.

Textured foil facings

Both sides of the PIR board feature a textured foil facing, providing a robust surface and contributing to the thermal performance of the insulation system.

Reduced heat loss through external walls

Installing high-performance Unilin PIR cavity wall insulation helps reduce heat transfer through the building envelope and can contribute towards improved energy efficiency.

Engineered board jointing

The CavityFill system incorporates engineered jointing to help create a more continuous layer of insulation when boards are correctly installed.

Where Can 140mm XT/CF Be Used?

Unilin XT/CF 140mm is intended for full-fill cavity wall insulation in new external masonry cavity walls. It can form part of a wall construction incorporating an inner blockwork leaf, insulation, residual cavity and external brick or masonry leaf.

The required insulation thickness and resulting wall U-value depend on the complete construction, including the blockwork, brickwork and other components. Unilin's published thermal calculations demonstrate that 140mm XT/CF can achieve wall U-values around 0.17–0.19 W/m²K in the stated example constructions.

Cavity Wall Insulation for UK Construction

For builders, contractors and self-builders looking for 140mm PIR cavity wall insulation, Unilin XT/CF provides a high-performance option for full-fill masonry cavity wall construction. Its combination of 0.021 W/mK thermal conductivity, 140mm thickness and 10mm residual cavity makes it suitable for projects where thermal efficiency and effective use of cavity space are important.

Always check the manufacturer's latest technical documentation and ensure the complete wall build-up is suitable for the intended project before installation.