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

URN: 3001017
£30.75ex. VAT £10.68 per m2
£30.75ex. VAT
£10.68 per m2
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100mm Celotex GA4100 is a high-performance thermal insulation PIR board with composite foil facings. It can be used for roof, floor, wall and timber joist applications.

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Fri 21 Jun

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Mon 24 Jun

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Product Overview

100mm Celotex GA4100 is a high-performance thermal insulation PIR board with composite foil facings. It can be used for roof, floor, wall and timber joist applications.

URN: 3001017
£30.75ex. VAT

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Standard (Nationwide) Delivery

Insulation, Plasterboard and Drylining Products
Under £150 ex. VAT £50 ex. VAT
Between £150 - £400 ex. VAT £35 ex. VAT
Over £400 ex. VAT FREE
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Between £100 - £300 ex. VAT £20 ex. VAT
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Screws & Fixings and Adhesives & Sealants
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Thermafleece CosyWool Roll & SupaSoft Insulation
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2 £60 ex. VAT
3 to 12 £70 ex. VAT
13 to 24 £140 ex. VAT
25 to 36 £210 ex. VAT
37 to 48 £280 ex. VAT
49 to 60 £350 ex. VAT
61+ £420 ex. VAT
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17 to 20 £350 ex. VAT
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* Deliveries of Doors and Panels to Scotland may incur additional costs and may have an extended delivery time of an additional 3 working days. Delivery to the postcodes below will be charged an additional delivery fee. Our customer service team will reach out to you if you order requires an additional delivery charge. This will be calculated based on the difference between the standard cost charged and the total cost outlined below:

Postcodes: KA1-29, IV1-39, AB, PH1-41, DD, PA1-19, KY, FK, FK15-21 - £100 ex VAT (total delivery cost)
Postcodes: KW 1-14 - £130 ex VAT (total delivery cost)
Highlands and Island: £305 ex VAT (total delivery cost)

1+ £16.50 ex. VAT

Express Delivery

Express Delivery - Insulation and Plasterboard & Drylining
Under £400 ex. VAT £50 ex. VAT
Over £400 ex. VAT £35 ex. VAT
Express Delivery - Timber & Sheet, Building Materials, Doors & Joinery and Gardens & Landscaping Products
Under £300 ex. VAT £50 ex. VAT
Over £300 ex. VAT £35 ex. VAT

This charge is based on delivery to mainland UK excluding the Scottish Highlands. If your delivery address is in the Scottish Highlands a member of our customer service team will contact you prior to processing your order should an additional delivery charge apply. We do not offer deliveries outside the UK mainland.

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We offer a 30 day returns policy on any faulty products.

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Key Features

  • {{home}} Use in floors, framed walls and pitched roofs
  • {{grade}} Aluminium composite facing on both sides
  • {{thermostat}} 0.022 W/mK thermal conductivity
  • {{build}} Easy to handle and install
  • {{public}} Zero Ozone Depletion Potential (ODP)
  • {{verified_user}} BBA certified

Technical Specification

Technical Specification
Material Type:PIR
Sales Unit:Board
Sales Unit Coverage:2.88m2
Manufacturer's Reference:GA4100
Thermal Conductivity:0.022W/mK

What Is 100mm Celotex GA4100?

Houses will always lose heat; heat loss will not only harm your comfort levels but will also make a dent in your pocket and the planet. This is where 100mm Celotex GA4100 comes in. 

100mm Celotex is a high performance, versatile insulation solution, which can be used for roof, floor, wall and timber joist applications.

The 2.4m x 1.2m boards are manufactured with a specially designed blowing agent that has a low potential to cause global warming. This is demonstrated in the fact that the boards have zero ozone depletion potential (ODP) and low global warming potential (GWP). 

What's more, 100mm Celotex PIR boards showcase low-emissivity foil facings on either side which increase their thermal performance in sealed air cavities; producing a superior U Value to other insulation solutions on the market with a thermal conductivity of just 0.022 W/m.K.

Where Is 100mm Celotex GA4100 Used?

As a general application insulation board (implied by the 'GA'), this BBA certified PIR insulation board can be used in a wide variety of building applications; including solid masonry internal linings, timber joist floors (including suspended timber joist floors), and timber frame studs. 

Not only that, but it can also be used in solid floor systems such as screed and concrete slab floors. 

100mm Celotex GA4100 can be specified for use in a variety of applications including:

  • Pitched roofs
  • Solid masonry walls
  • Timber frames & steel framed systems
  • Timber frame internal linings
  • Floors - screed, concrete slab and timber joist floors
  • Loft insulation – between and over timber joists (pitched roof)
  • Timber frame sheathing (external wall)
  • Between timber frame studs (external wall)
  • Solid masonry internal linings (external wall)

If you're looking to insulate flat roofs at a great price, we stock plywood insulation specifically engineered to insulate flat roof applications. 

100mm Celotex GA4100 Benefits

100mm Celotex GA4100 insulation is a multi-purpose insulation board that comes in dimensions of 2.4m x 1.2m. 

Not only do these 100mm Celotex boards offer excellent thermal performance, but they are also moisture resistant thanks to their closed-cell structure. 

This excellent drying potential sets you up for years of consistent thermal performance and reduced energy bills - thus, promising maximum protection for the lifetime of your build.

Let's have a look at the specs:

  • Suitable for use in a number of applications including roof, wall and floor systems
  • Thermal conductivity of 0.022 W/mK
  • Moisture-resistant
  • Low Global Warming Potential (GWP) and Zero Ozone Depleting Potential (ODP)
  • Achieves an A+ rating when compared to the BRE Green Guide 2008
  • Cutting-edge low emissivity foil facing significantly enhances the thermal efficiency within sealed cavity air spaces
  • Easy to cut and shape
  • Provides reliable long-term energy savings for buildings

100mm Celotex GA4100 Insulation Board Certifications

BS EN is British and European Standard Specifications. With over 100 years of experience, the British Standards Institute is recognised as the UK’s National standards body.

  • Spread of flame: Euroclass E Reaction to Fire classification, according to BS EN 13501-1
  • Thermal conductivity of 0.022 W/m.K, reducing the thickness of insulation required to hit the target U-value - BS EN 12667
  • Compressive strength: ≥140kPa - BS EN 826
  • BRE Green Guide Rating of A for sustainability - which can assist in demonstrating environmental performance in your BREEAM assessments
  • BBA certified for use in defined roof, wall and floor applications 
  • Manufactured in accordance with quality management systems (BS EN ISO 9001:2000)

100mm Celotex GA4100 Insulation Storage & Handling

Due to their light and portable nature, 100mm Celotex boards can also be handled and transported easily. 

If you need to store 100mm Celotex boards for a while before installation, you should choose a cool, dry space.

Our rule of thumb when it comes to storage is that the boards should not be stored on the ground. Instead, store them on a level surface and under a protective cover. 

About Celotex

Celotex is a leading British manufacturer of 100mm PIR insulation. Founded in the early 1920s, the company has since evolved from a fibreboard insulation company to one that solely focuses on PIR insulation boards.

The GA4100 insulation board is just one of many popular thermal insulation solutions in the Celotex product range.

It comes from the GA4000 product group, which includes 6 other thicknesses. 

We stock the following GA4000 Celotex products: 

What the pros say about 100mm Celotex…

100mm Celotex GA4100 is just about the most common insulation product in the UK. The term “commodity” doesn’t even come close. 

Its enduring popularity is due in most part to its high level of thermal efficiency balanced with its reasonable price, making it both efficient and affordable, unlike more premium products like phenolic (more expensive) or cheaper products like fibreglass (less thermally efficient).


Although Celotex will claim superiority over other manufacturers, Celotex PIR insulation is really no different to the PIR boards made by the likes of EcoTherm, Recticel, and Kingspan (it’s a crowded market). 

As a commodity product that is heavily dependent on one central ingredient (MDI), its price is prone to sharp fluctuations in response to supply and demand. 

This presents a cost forecasting nightmare for builders and buyers; not helped by the fact that this product is installed in pretty much every house in the United Kingdom.


Like it or loath it, 100mm Celotex is here to stay.

Other Celotex Products

Customer Reviews

5/5 based on 37 reviews

Friendly customer service team to help me with my order

Hilary Smith on

Celotex is my first choice PIR board. Price and delivery times from Materials Market was great, thanks.

Paul Wilson on

Part of a summerhouse I built. I found them really easy to cut to fit into walls and then they slotted in nicely with some insulation tape to keep them in places and ensure there we no gaps anywhere.

Mark Plunkett on

5-star insulation and a 5-star service

Jim G on

Great product. You decent get coverage with each board and they are so lightweight, making them easy to transport around the building. Materials Market customer service was fantastic as well.

Simon Walters on

I used this in a suspended floor at home. It took a bit of time for me to fully install, but the boards are simple to cut and slide relatively easily in-between the beams. It's a good product and I'd recommend it.

Kris W on

Great board and great service. I'll buy again

Gene Krupps on

Good product for the job

Peter Scrills on

Managed to get a good rate after I spoke with someone over the phone

Michal V on

Not the first time I've this from these guys, and won't be the last. Spot on every time.

Gaz Long on

Boards are lightweight to move around the job

Luke Wheeler on

Used this under some floorboards, simple to handle and install.

Jay Cross on

Managed to grab this at a good price compared to other websites

John A on

I used this in my roof rafters ahead of the winter

Julia Finn on

The delivery driver was really nice when he dropped the boards off

Vivian K on

5 star product. Service was great as well

Harry D on

Excellent service and board

Jess L on

Came as expected and easier to cut with a hand saw than I first thought

Len Hill on

On time and customer service was good to help resolve a small issue

Simon C on

Top service. The boards came on time for my project

Barry G on

light and simple insulation to work with

Hank P on

Used this is in a partition wall and found them easy to cut. Delivered quick, with a cheap price

Sal Smith on

arrived as described and expected

Gerry Hall on

These easily slid in under the boards of my ground floors

Ian Frutton on

Thanks - came on time for my work

Gerry Klick on

I bought these for a big timber framed floor system job, arrived on time and the customer service team were really helpful.

Joel Simmon on

Great product, easy to work with and meet all national building regulations

Jake Cullens on

Simple to install in the timber rafters for my loft conversion

Jolie P on

Competitive price, fast delivery, and good quality product. Great insulation.

Martin Chivers on

Used this product between timber joists and timber rafters and it worked wonderfully. Loft is now incredibly toasty. Shipping costs were free after £500 spend.

John Berry on

So cheap! Much cheaper than getting it at my local Travis Perkins

Colin Gurn on

My rooms were warmer after I installed the insulation

Jack H on

My rooms were warmer after I installed the insulation

Jack H on

Easy to install and manoeuvre

Kay H on

Easy to cut and fit into walls

Mark Thomas on

Excellent insulation!

Chris Shulte on

Used in steel framed systems. Great insulation board!

Travis Bluesky on

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