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: 50mm, 60mm, 75mm, 85mm and 100mm.


Product options

Quantity Product ex-VAT inc-VAT  
£42.73 £51.28
£44.65 £53.58
£780.38 £936.46
£41.96 £50.35
£9.32 £11.18

Availability Indicators

Celotex CW4000 is sent out from depots nationwide and is subject to the Local Depot Delivery minimum order levels and delivery charge thresholds.

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.

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

  • Generally 1 to 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

Delivery charges will be calculated at check-out. Please visit our Ordering From Us page for further details on minimum order levels and delivery charges. If you have any queries, please do not hesitate to contact me via our Contact Form or on 01903 899 898.

Product Application

Partial fill cavity wall insulating board

Celotexs 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

Core: 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).

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

Product Properties

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

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 Variants

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.