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40mm Celotex CW4000 Cavity PIR Insulation Board ǀ pack of 14

40mm Celotex CW4000 PIR Rigid Insulation for Partial Fill Cavity Walls - pack of 14 (CW4040)
40mm Celotex CW4000 Cavity PIR Insulation Board ǀ pack of 14
  • Lightweight - Squared edges
  • Partial Fill Masonry Cavity Walls
  • Low emissivity foil facing
  • Achieves a BRE Green Guide A rating
  • BBA approved – certificate 16/5343
Estimated delivery:
In Stock
£ 83.88
Ex VAT: £ 69.90
  • Brand: Celotex®
  • Model: 40mm CW4000
  • Dimensions: 1,200mm x 450mm x 40mm
  • SKU: 40mm
  • Product code: P1-891
  • MPN: 40mm Celotex CW4040

Options available

40mm Celotex CW4000 Partial Fill Cavity Wall Insulation Board (CW4040) is an easy to install PIR (polyisocyanurate) rigid insulation board, featuring a low emissivity foil facings with excellent thermal conductivity of 0.022 W/mk that is suitable for partial fill masonry cavity wall applications.

Celotex CW4040 is a high-performance cavity wall insulation board with an excellent thermal performance that comes in easy to handle board size 1200mm x 450mm, designed to fit between standard wall tie spacings to reduce the heating and cooling costs within the building.

This premium cavity wall insulation board by Celotex provides improved thermal performance in cavity air spaces, helping to hit the required U-value and improving living conditions by reducing energy costs.

Celotex CW4000 range is a highly versatile and durable, BBA certified cavity insulation board assessed for its defined applications and is compliant with the relevant Building Regulations.

Cavity Wall Board Celotex CW4000 is a sustainable product which achieves a BRE Green Guide Rating of A, demonstrating its environmental performance in BREEAM applications.

Celotex CW4000 is chemically inert and safe to use manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP).

CW4000 will help you to meet the requirements of UK thermal building regulations and reduce heat loss.

Celotex Cavity Insulation Boards can be readily cut by bricklayer using a sharp knife.

All products must be installed in accordance with guidance issued by Celotex.




Thickness: 40mm

Size: 1200mm x 450mm

Board coverage: 0.54m2

Pack coverage: 7.56m2

Density (Foam Core): 30Kg/m3

Thermal Conductivity: 0.022 W/mk

R-Value: 1.80m2K/W

Commpressive Strength: 120kPa

Water Vapour Resistivity: >100 MNs/gm

Surface spread of flame: Class 1


Key points:

 · BBA approved.

 · Green Guide Rating A+.

 · Thermally efficient product.

 · Easy to handle boards for installation between cavity wall ties.

 · Low emissivity foil facings on both sides.

 · Zero ozone depletion potential and low global warming potential.

 · Polyisocyanurate (PIR) rigid foam core.

 · Celotex CW4000 has a declared thermal conductivity of 0.022 W/m.K.

 · Euroclass E Reaction to Fire classification, according to BS EN 13501-1.

 · All Celotex products are manufactured under Environmental Management System – ISO 14001:2015.

 · All Celotex products are manufactured under Quality Management Standard – ISO 9001:2015.


Limitations of use:

Celotex CW4000 should not be used in the external walls of buildings over 18m in height (England and Wales) or 11m in height (Scotland). 

Recent changes to Building Regulations mean that only non-combustible insulation or insulation of limited combustibility can be used in buildings of that height.



 · BBA Approved (Cert no. 16/5343) for partial fill cavity walls.

 · CE Marked (18.DOPCW4000-01) to BS EN 13165.


Please note, 40mm Celotex CW4000 (CW4040) is sold in full pallets only.

We can offer you:




*Further information may be found in our Downloads section.

Fairly easy access to all PDF files.

Datasheet ǀ Declaration of Performance - DoP ǀ BBA Certificate ǀ Installation Guide ǀ Certificates ǀ Brochure ǀ SPEC Sheet 


*Special Product - Non returnable cancelable.

Board covarage 7.56 m2
Commpressive Strength 120kPa
Density 30Kg/m3
Length 1200mm
Material PIR (polyisocyanurate)
Profile Improved thermal performance
R-Value 1.80m2K/W
Size 1200mm x 450mm
Surface spread of flame Class 1
Thermal Conductivity 0.022 W/mk
Thickness 40mm
Water Vapour Resistivity 100 MNs/gm
Width 450mm
Vapour Resistivity 100 MNs/gm
Building Regulations Compliant
Finish Foil facings
Shipping method Articulated Vehicle
Applications Cavity Walls ǀ Masonry Walls
BBA Certified Yes (no. 16/5343)
ETA Notification Yes
Features High-performance Cavity Wall Board
Manufacturer Celotex CW4000®

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We deliver insulation materials to Mainland UK only. Deliveries to Highlands, Northern Ireland, Isle of Wight etc.. might be possible at additional cost.
We offer free delivery on most of the orders above £300 (excluding VAT) (except special products - shipping cost via courier - products marked ''Request A Quote'')

Delivery of some insulation materials might be extended due to the current situation (Covid-19, stock shortages, allocations).
If you need materials quickly please contact us - we will do our best to help you source materials needed.

We do not deliver on weekends and bank holidays. Sometimes we can deliver on Saturdays - please check with us before placing the order.
If you need any further information please contact us tel. 02081910776

We can help to calculate price per m2 or linear meter (one meter in length) cost, please just contact us via phone 02081910776, email or live chat. Alternatively, you can work it out yourself quickly and easily: to get cost per meter square please divide price shown in orange area by ''Required area (m2)'' Example price of £28.80 divided by board coverage 2.88m2 = cost of £10.00 per m2.


No matter whether you choose a local installer or a national company, there’s a few tips to help you find the right installer for your home insulation improvements, such as asking for recommendations and making sure that they’re part of a certification scheme. This makes sure that they have the right skills and standards of workmanship to carry out the installation, and you can be sure that they know exactly what they are doing.


1. Thermal inspection picture in portfolio

It’s worth seeing a installer’s previous work. There’s no harm asking if you can see any properties nearby that they’ve installed insulation in. Best way would be to see Infrared Thermal Imaging Inspections. Thermal cameras spot small, but key changes in temperature in different areas of a house, identifying problematic areas that the human eye never could and some that a visual inspection could only hypothesize.

2. Reviews

Along with checking recommendations and previous work, finding reviews online can often be a great way to find out if they provide a good service or not. However, it’s best not to solely rely on reviews you may find or review websites, as there’s no controlling who writes them.

3. Compare prices

Comparing prices will also ensure companies can’t take advantage of you and give you a fair price. 

4. Word of Mouth

The best way to find a great insulation installer is through recommendations. Make sure you ask friends and family. They will most likely give you their honest opinion and can tell you from first hand experience.


Whether you require a wall, cladding, external wall, loft or floor insulation fitted, you can find and hire your local insulation installers from popular UK web pages. A simple internet search will return thousands of potential installers near your area.



We are the stockist of construction materials and related products for both trade and DIY from most recognizable brands in the UK like Cordek, RCM, Promat, Rockwool, Isover, Celotex, Xtratherm, Ursa, Low-E, Cedral, Kingspan, Dufaylite, British Gypsum, K-rend, Ecotherm, Iko enertherm, Kay-Metzeler, Terrawool to allow you to complete your insulation job on time at competitive prices and the highest standards.


Whether you are a large company or a DIYer, if you need a large amount of insulation materials, we can offer quantity discounts at the best prices. Please contact us and our friendly customer service will try to find the best and cheapest solutions for you. We value your time and we will try to deliver the products as soon as possible at a reasonable price to your construction site or house. The UK's leading insulation supplier near you and your needs. Price List available upon request.
40mm Celotex CW4000 PIR Rigid Insulation for Partial Fill Cavity Walls - pack of 14 (CW4040)
40mm Celotex CW4000 Cavity PIR Insulation Board ǀ pack of 14
£ 83.88