Celotex CW4000 partial fill cavity wall board Celotex Insulation

Celotex CW4000

High performance rigid Polyisocyanurate (PIR) partial fill cavity wall insulation board.

Comes in conveniently sized boards for installation between cavity wall ties.

Includes low emissivity foil facings giving improved thermal insulation performance within cavity air spaces.

Can be used to provide energy performance of new and existing buildings.

BBA certified.

Provides reliable long term energy savings for buildings.

Thicknesses and Availability:

Available in most popular thicknesses at most depots; short lead-times may apply if we need to get stock in before delivering to site.

This CW4000 Range includes the following available product thicknesses: 40mm, 60mm, 70mm, 75mm, 80mm, 90mm and 100mm.

Product Information

General information about Celotex CW4000

Product Application

Partial fill cavity wall insulating board

Celotex's high performance polyisocyanurate (PIR) foam board, CW4000, is suitable for use in partial fill cavity wall applications with a minimum 50mm residual cavity.

Product Make-up


Celotex CW4000 is manufactured from rigid polyisocyanurate (PIR) using a blowing agent that has zero ozone depletion potential (zero ODP) and low global warming potential (GWP).


Faced on both sides with a low emissivity aluminium foil, autohesively bonded to the insulation core during manufacture.

Product Properties

Thickness 40mm to 100mm
Board Length 1.2m
Board Width 0.45m
Board Edge Square

Product Prices

Buy Celotex CW4000

Product ex-VAT inc-VAT
Celotex CW4050 50mm, 11 x 0.45x1.2m = 5.94m² £53.32 £63.98
Celotex CW4075 75mm, 8 x 0.45x1.2m = 4.32m² £57.36 £68.83
Celotex CW4085 85mm, 7 x 0.45x1.2m = 3.78m² £59.55 £71.46
Celotex CW4100 100mm, 6 x 0.45x1.2m = 3.24m² £55.92 £67.10
Aluminium Foil Tape 100mm x 50m = 50lm £10.17 £12.20

Reasonable stock levels are generally held at most of our depots. In some geographic locations, depots may stock alternates, however, we will contact you to discuss before proceeding with the order.

Where products need to be brought in from Celotex, please allow approx. 1 week for delivery.

  • Generally 1 or 3 working days for delivery
  • Generally 1 to 5 working days for delivery
  • Generally 5 to 10 working days for delivery
  • Special request or made to order item, allow extended lead times. Minimum order levels may apply.
  • Please call to check availability and approximate lead times

Product availability depends upon stock levels at closest depot and delivery logistics to geographic locations

Product Performance and Guides

Product Performance, Manufacturer Downloads, and Installation Guides

Product Performance

Thermal Conductivity 0.022 W/mK
Compressive Strength 120 kPa at 10% compression BS EN 826:2013
Vapour Resistance > 300 MNs/gm
Product Thickness Thermal Resistance kg/m²
Celotex CW4040 40mm 1.80 m²K/W 1.41 kg/m²
Celotex CW4050 50mm 2.25 m²K/W 1.92 kg/m²
Celotex CW4060 60mm 2.70 m²K/W 2.26 kg/m²
Celotex CW4075 75mm 3.40 m²K/W 2.78 kg/m²
Celotex CW4085 85mm 3.85 m²K/W 3.13 kg/m²
Celotex CW4100 100mm 4.50 m²K/W 3.65 kg/m²
While we have provided Thermal Resistance values for all thicknesses on the Celotex CW4000 datasheet, some thicknesses may not be readily available.

Product Certificates

Please visit the Celotex website for product certificates.