Celotex CW4100 Cavity Wall Insulation Board 100mm x 450mm x 1200mm 3.24m2

£75.04 £62.53
In stock
Product Description

Celotex CW4100 Cavity Wall 100mm is an easy-to-install polyisocyanurate (PIR) insulation board with excellent thermal performance, featuring a low emissivity foil facing which improve thermal insulation. Available in thicknesses from 40mm to 100mm, it is designed for use in partial-fill cavity wall applications.

Board size: Width 450mm, Length 1200mm

Pack: 6 boards

Other available thicknesses: 50mm & 75mm


We are happy to help with enquiries, stock availability or any technical help you require, however for security reasons we cannot take orders over the phone. So if you need to chat give us a call on 03301231761 or email us at [email protected].

What is Celotex CW4100 100mm? 

Celotex CW4100 100mm includes a polyisocyanurate rigid foam and insulation core, helping you keep your energy bills down and retain the warmth in your building. This material is incredibly effective and fits conveniently in between cavities, delivering a thermal conductivity of 0.022 W/mK. 

This insulation board has been manufactured using a blend of blowing agents with low global warming potential (GWP) and zero ozone depletion potential (ODP), making them a green insulation solution.


Features and benefits of Celotex CW4100 100mm:


  • Excellent thermal conductivity of 0.022 W/m.K, reducing the thickness of insulation required to hit the target U-value.
  • Low emissivity foil facing provides improved thermal performance in sealed cavity air spaces.
  • Easy to install – light and rigid boards assisting with ease of transportation, handling, and fitting. 
  • Sized to fit standard wall tie spacing for ease of installation.
  • BBA certified – fit for use in defined partial fill cavity wall applications if installed, used, and maintained as set out in the certificate.
  • Celotex CW4000 achieves a BRE Green Guide Rating of A, demonstrating environmental performance in your BREEAM assessments.
  • Board size: width 450mm, length 1200mm
  • Thickness: 50-100mm
  • Material: PIR
  • Water vapour resistance: greater than 150MNs/g
  • Zero ozone depletion potential (ODP) and low global warming potential (GWP)

Applications for Celotex CW4100 cavity insulation boards 100mm: 


  • External Walls – partial fill cavity wall

Learn about the brand as well as other insulation products with our Celotex buyer’s guide

Data Sheet (613.82 kB)
Customer Questions
For the 100mm cavity slabs what is the coverage?
The Celotex CW4100 100mm cavity wall boards are sold in a pack of 6 which covers 3.24m2.
Can the boards be installed in my roof between the joists?
The CW4000 boards are specifically intended for use in a cavity wall, as they are pre cut to size to fit standard wall tie spacing. There is no reason why you could not use the cavity boards between joists, however we would advise looking at the larger GA4000 boards. The GA4000 is the same material but in larger sheets. 
How thick should I go with my cavity insulation?
Celotex manufacture the CW4000 cavity boards up to 100mm. We would advise consulting a builder or speaking to Celotex who can help with technical calculations including U-values. 
Did you find what you were looking for?
More Information
Supplier Part NumberCW4100
Pack Size6
Size1200mm x 450mm

Orders and Delivery

Free delivery if your order is over £300 ex VAT. Orders between £100 - £300 ex VAT will be subject to a delivery charge of £50 ex VAT. Please note, we are unable to accept orders less than £100 ex VAT

When ordering on line you can specify the date of delivery, however we would not be able to specify the time of delivery on that day.

• Please note that we have a number of large vehicles, including articulated vehicles that may be used for delivery. Please advise us in the comments on your order if access to the delivery address is limited.

• Due to insurance guidelines, delivery personnel are unable to enter private residences. Delivery will be as far as possible to the kerbside of the delivery address. The recipient of the products is responsible for any additional lifting once the delivery has been made. Please bear in mind that Insulation products can be bulky and / or heavy.

• The delivery driver will require a signature to confirm the goods have been received.

 † Unfortunately we, Insulation Express, cannot deliver to the Highlands & Islands of the UK. However we will be happy to deliver to a freight forwarding company on your behalf.


Returns and Refunds

In the unlikely event that you need to return an item, please contact our team on [email protected] within 14 days of accepting delivery of the item.

Restocking charges may apply. We will discuss this with you upon receipt of the cancellation request. Restocking charges will be applied where the products are no longer required AND NOT for goods returned because either defective or damaged.

We usually charge 30% of value (minimum £25.00).

Please note that we cannot accept returns on special orders. Special orders may consist of items sent via third party shipping companies or made to measure products. If you are unsure on whether or not your item is a special order, please contact us on [email protected] prior to placing the order.

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