Celotex GA4100 Insulation Board 100mm x 1200mm x 2400mm

£32.75 £27.29
In stock
Product Description

Celotex GA4000 is an easy-to-install polyisocyanurate (PIR) insulation board with excellent thermal performance, featuring a low emissivity foil facings which improve thermal insulation. It can be used in roof, wall, and floor applications.

Size: 100mm x 1200mm x 2400mm

Other available thicknesses: 25mm, 30mm, 40mm, 50mm, 60mm, 70mm, 75mm, 80mm, 90mm, 120mm & 150mm



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 GA4100 100mm? 

Celotex GA4000 insulation board eliminates cold spots while being flexible and can fit in a variety of spaces such as a floor, wall, and roof. As PIR boards, they are rigid and lightweight, so you can transport them with ease. These high-quality multi-purpose insulation boards help you cut down on your energy use. Celotex insulation products have zero ozone depletion potential (OPD) and low global warming potential (GWP), with the materials involved in manufacturing being environmentally friendly.

Celotex GA4000 insulation boards have been scored with a class 1 fire rating, meaning they don’t catch fire easily.

Is 100mm PIR insulation enough?

This depends on where in your building you plan on installing the insulation. 90mm of PIR is the minimum acceptable level of insulation for a wall whereas 100mm in the roof is too thin.

100mm Celotex is one of the most popular Celotex insulation thicknesses.


Features and benefits of Celotex GA4100 100mm: 


  • Excellent thermal performance with a thermal conductivity of 0.022 W/m.K.
  • Low emissivity foil facing provides improved thermal performance in sealed cavity air spaces.
  • Easy to install – Celotex boards are light and rigid, assisting with ease of transportation, handling, and fitting.
  • BBA certified – Celotex GA4000 has been assessed by the BBA as fit for use in defined roof, wall, and floor applications if installed, used and maintained as set out in the certificate.
  • Celotex GA4000 achieves a BRE Green Guide Rating of A, demonstrating environmental performance in your BREEAM assessments.
  • Lightweight 2400 x 1200mm boards.
  • Low emissivity foil facing.

Applications for Celotex GA4100 insulation boards 100mm: 


  • Ground Floor - Concrete Slab
  • Ground Floor - Suspended Timber Joist
  • Ground Floor - Beam and Block
  • Ground Floor - Upgrading Existing Concrete Slab
  • External Wall - Timber Frame Internal Linings
  • External Wall - Timber Frame Sheathing
  • External Wall - Between Timber Frame Studs
  • External Wall - Solid Masonry Internal Linings
  • Pitched Roof - Over Timber Rafters
  • Pitched Roof - Sarking
  • Pitched Roof - Below Timber Rafters
  • Pitched Roof - Between Timber Rafters
  • Pitched Roof - Loft insulation - Between and Over Timber Joists
  • Flat Roof - Balconies & Terraces Over Joists
  • Flat Roof - Between Timber Joists
  • Flat Roof - Below Timber Joists

If you are considering using Celotex as part of your building and renovation works, find out more and read our guide on the applications of Celotex insulation boards

Data Sheet (213.70 kB)
Customer Questions
What do I use to seal the joints between the GA4100 boards?
We would recommend using foil tape to seal the joints between GA4100 and any PIR insulation boards.
Is the thermal value of GA4050 the same as GA4100?
When comparing thermal values of a product it is important to understand the difference between an U-value , R-value and Lambda Value. It is the same material on the whole GA4000/TB4000/XR4000 ranges, which is PIR insulation. The boards have the same thermal conductivity, but it is the thickness which will determine the thermal value. You can use the u value calculator and fine out more information on the prodcuts in the data sheet. Both can be found on the prodcut page.
Did you find what you were looking for?
More Information
Supplier Part NumberGA4100
Size1200mm x 2400mm

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.

Write Your Own Review
You're reviewing:Celotex GA4100 Insulation Board 100mm x 1200mm x 2400mm

Free delivery on orders over £300! Terms and Conditions apply

For all your roofing needs

Check out our new website!

 Buy Power tools online