Celotex Is Now Sopratherm: What the Soprema Rebrand Means for You

What has genuinely changed is the paperwork. Datasheets, Declarations of Performance and certificates have been reissued under Soprema and Sopratherm names, which matters if you are submitting documents to Building Control or a warranty provider. That is the part most guides skip, so it is covered in full below, along with the name mapping, the fire and height guidance, and the questions buyers keep asking.

The Short Version

What Happened to Celotex, and When

The rebrand is the end point of a corporate process that started several years earlier, and it covers more than Celotex.

Two points worth holding onto. First, this is a portfolio-wide tidy-up across insulation and waterproofing, not something aimed at one brand. Second, the manufacturing sites are unchanged: Hadleigh and Eggborough both still appear as the production locations on the current Sopratherm Environmental Product Declarations, which is the documentary backing for the "same board, same factory" position.

Does Saint-Gobain Still Own Celotex?

No. Saint-Gobain sold the business, retaining only a 25% minority stake for the transition period after the 2024 completion. The boards are supplied by Soprema UK.

Celotex to Sopratherm: The Full Name Mapping

Soprema kept the alphanumeric codes, which is the single most useful decision it made for anyone ordering. If you know the code, you can still find the board.

Rigid PIR Boards

Individual boards follow the same pattern all the way down: Celotex GA4075 becomes Sopratherm GA4075, Celotex XR4150 becomes Sopratherm XR4150, Celotex TB4025 becomes Sopratherm TB4025, and so on.

Where the Sopratherm Name Does Not Apply

This is the detail that trips people up. The naming rule is not uniform, and any guide telling you that everything is now called Sopratherm is wrong.

Is Sopratherm the Same as Celotex?

For the 4000 series PIR boards, yes. For anyone specifying, ordering or fitting these boards, the practical answer is that almost nothing has moved.

• Declared performance. Thermal conductivity remains 0.022 W/mK across the TB4000, GA4000 and XR4000 boards, with the same figure for the PIR core in PL4000.
• Board sizes. The standard 2400mm x 1200mm sheet is unchanged, as are the smaller cavity board formats.
• Facings. The composite aluminium foil facings are the same.
• Reaction to fire. Classifications are unchanged and still declared to BS EN 13501-1.
• Installation. Cutting, mechanical fixing, adhesives, taping, jointing and storage are all as before. No method statement needs rewriting because of the name.
• Manufacturing. Same two UK plants, same production.

If a specification on a live drawing says Celotex GA4090, a delivery of Sopratherm GA4090 satisfies it. The board is the same product under a new brand name. Always install in line with the current Soprema technical guidance and the project specification.

What Has Changed: The Documentation

Here is the part worth reading twice, because it is the one that creates real problems on site if it is missed.

Technical Data Sheets, Declarations of Performance and Environmental Product Declarations have all been reissued under Sopratherm names and are hosted on the Soprema platform. The Environmental Product Declarations were updated on 18 March 2026, covering Sopratherm TB4000, GA4000, XR4000 and CW4000 under one registration, with PL4000 registered separately.

Do I Need to Download New Datasheets?

Yes, for any live project. A Celotex datasheet downloaded in 2022 is superseded and should not be submitted to Building Control or a warranty provider. Pull the current Soprema document instead.

Is the BBA Certificate Still Valid?

The rigid boards sit under BBA Certificate 25/7318, issued on 10 January 2025 and superseding the previous certificate 17/5405. Note that the certificate change slightly predates the January 2026 rebrand: the certificate was reissued to Soprema Insulation Limited during the transition, before the customer-facing name change landed. If your project file still carries a 17/5405 reference, it is out of date regardless of what the boards are branded.

What Else Has Moved

• Internal product codes. Even where the trade name is identical, the underlying stock codes changed. GA4050 now carries product code 00311678 and GA4060 carries 00311679, for example. That will matter to anyone reconciling delivery notes against purchase orders.
• Bookmarked technical links. Resources previously hosted on the Celotex domain are being consolidated onto the Soprema platform, and the old U-value tools have been replaced by a dedicated Soprema calculator.

Fire Classification and the 11 Metre Rule

Two things are worth stating plainly here, because both are handled loosely elsewhere.

First, the reaction to fire classification is not the same across the range. Sopratherm TB4000, GA4000 and XR4000 are Euroclass F to BS EN 13501-1. Sopratherm PL4000, being a plasterboard-faced laminate, is Euroclass B-s1,d0. A single fire figure cannot be applied across the whole Sopratherm range, so always check the classification for the specific board you are buying.

Second, on building height. Soprema states that its PIR products, including Sopratherm and Thermaclass, should not be used within the external wall construction of a building containing a storey more than 11 metres above ground level. In England that follows Approved Document B, which requires materials in those walls to achieve Euroclass A1 or A2-s1,d0, a classification PIR does not meet.

That 11 metre figure is the England position. Scotland, Wales and Northern Ireland operate their own building standards, so check the guidance for the nation your project sits in rather than assuming the same threshold carries across. If you have seen 18 metres quoted on a merchant page, that figure is out of date wherever you are. Work to the threshold that applies in your jurisdiction and confirm against the current building regulations guidance and the project specification.

Which Boards Will You Receive From Us?

Celotex-branded while our current stock lasts, then Sopratherm-branded once it changes over. Either way, the same board.

We are still holding Celotex-branded stock in our Rotherham warehouse and will supply that until it is sold through. When Sopratherm-branded stock replaces it, that is what will arrive on your delivery. Legacy Celotex-branded boards remain fully valid and usable on site, so packaging in the older branding is not a cause for concern and does not need rejecting.

Whichever branding turns up, you are buying a board covered by the same BBA certificate and the same declared performance figures set out above. Our product listings will continue to carry the Celotex name for the foreseeable future, because that is still how the overwhelming majority of people search and order. If a delivery arrives Sopratherm-branded against a Celotex order line, match the code rather than the brand name and you will find it is the board you ordered.

The Bottom Line

Celotex has not been discontinued, reformulated or quietly downgraded. It has been folded into Soprema's portfolio alongside Chesterfelt and YBS Insulation, and the PIR boards now carry the Sopratherm name with their familiar codes intact. Order GA4075 and you get GA4075.

The one job worth doing is the document check: replace any saved Celotex datasheets with the current Soprema versions, make sure your certificate reference reads 25/7318 rather than 17/5405, and check the specific reaction to fire classification for the board you are using rather than applying one figure across the range. Do that and the transition costs you nothing.

Ready to order? Browse the full Celotex range, or use the mapping table above to go straight to the board you need.