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Celotex GA4100 General Purpose PIR Insulation Board - 2400 X 1200 X 100mm

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£49.76 Incl. VAT
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The endlessly versatile Celotex GA4100 multi-purpose insulation board is perfect for all sorts of applications such as pitched roofs, flat roofs, solid floors and masonry walls and steel framed and timber framed systems. Made of polyisocyanurate (PIR), it's easy to handle, cut and shape and so a convenient option. Thanks to an impressive thermal conductivity of 0.022 W/m.K, this high-performance insulation board delivers excellent thermal performance. With that mind, you shouldn't be surprised to find out that even though it's thinner than most similar products on the market, it easily meets the required U-value.

And that's not all! The innovative low emissivity foil facing dramatically improves thermal performance in sealed cavity air spaces, boosting the potential U-value even more. As you'd expect from Celotex, the GA4090 is manufactured to the highest industry standards. The BBA (British Board of Agrement) has approved it as fit for use in defined roof, wall and floor applications when installed, used and maintained according to the guidelines in the certificate. On top of that, the GA4100 has a BRE (Building Research Establishment) Green Guide Rating of A, which will help improve your environmental performance. Altogether, this PIR insulation board will provide reliable long-term energy savings for you and your home.

Features & Benefits: Celotex GA4100 General Purpose PIR Insulation Board - 2400 X 1200 X 100mm

  • High-quality PIR insulation board
  • Reduced thickness & excellent thermal performance
  • Lightweight, quick & easy to install
  • Suitable for use in roof, wall and floor applications
  • Low emissivity foil facings for improved thermal insulation performance in cavity air spaces
  • BRE Green Guide Rating of A for sustainability
  • BBA certified
  • R-Value: 4.50m2K/W
  • Maximum weight: 4.15kg/m2
  • Compressive strength (kPa): CS(10\Y)140

Standards & Certification

  • Thermal conductivity: 0.022W/m.K, according to BS EN 13165 for factory made rigid polyurethane foam (PU) product
  • Spread of flame: Euroclass E Reaction to Fire classification, according to BS EN 13501-1. Products with this level of classification are not provided with a rating for smoke emission.


Length 2400mm Thickness 100mm Width 1200mm


Thermal Conductivity 0.022 W/mK Edging Square Edge Facing Foil Product Type Board
Material PIR

Questions & Answers


can this product be used against the felt between the roof rafters?


While this product can be fitted between the rafters, you'd still want to leave a rough 25-50mm gap for ventilation. 


If I use these celotex,-ga-4100 rigid boards would I need to cover them with plywood in order to walk on them or would they take my weight without damage. I would also be looking to install a loft ladder for access.


While the boards do have a good compressive strength, it is still advisable to board over them so that weight can be dispersed. 


Can Celotex GA4100 be used between oversite blinding and 100mm of concrete as insulation layer


Ideally you'd have a DPM before any form of insulation is laid and then layering of ply over the top of this, we have an excellent guide on how you can incorporate PIR into a floor build up - https://www.insulationsuperstore.co.uk/help-and-advice/project-guides/insulation/insulating-a-floor/



Hello is this product suitable for underfloor insulation where full access is available - plenty of ventilation is also available. Would 100mm be an optimum thickness for this application ?


That would depend if you have been specified a thickness against the depth of the joists, as that would determine how thick the given insulation can be. 

Unfortunately we are not able to comment on what would pass/be the optimial thickness, this would be best suited for an Architect or perhaps even Building Control to advise on. 


Can Celotex be used as a cavity fire barrier?


No, where cavity fire barriers are required by national building regulations, they should be installed in line with the manufacturer's instructions.


Can Celotex be exposed to the ground?


We advise that when used in ground floors, Celotex must always be above the damp proof membrane (DPM ).


What is the U Value?


Unfortunately, we cannot calculate U Values. For this information, we recommend speaking to your builder or the manufacturer.

Have a question about this product?


5 / 5 24 reviews
31st May
Good insulation property
Zoe Roper
24th May
Good quality product delivered quickly and located at site with safety in mind.
Phillip Wheeler
10th May
I used this to insulate under my floor. I won't really know how effective it is until next winter but it feels very insulating. Some say the best way to cut it is with a bread knife, I actually found this a poor way as it is difficult to keep the blade straight. The best and most controllable way i found was with a saw using light hand pressure, straight cuts every time.
11th April
Brilliant boarding very insulative and easy to use and cut very light to handle
Sean Breakspear
10th February
Very good service, will be using again
1st February
Seems to be a really good product
Gary S
2nd August 2021
Great product with excellent spec.
Sam Turner
23rd June 2021
Excellant service and price
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Celotex GA4100 General Purpose PIR Insulation Board - 2400 X 1200 X 100mm

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