Buy Celotex Insulation Online: GA4000, XR4000, TB4000 and PL4000 (Now Sopratherm)
If you've been searching for Celotex GA4000, XR4000 or TB4000 boards and found the name "Sopratherm" instead, you're in the right place. Soprema bought Celotex from Saint-Gobain and has rebranded the range, so Celotex boards are now made and sold as Sopratherm, with the same product codes. This guide explains what's changed, what each Celotex range is for, and lists every Celotex/Sopratherm board we stock with live trade prices.
Quick answer
- Celotex is now Sopratherm. GA4000 is now Sopratherm GA4000, XR4000 is Sopratherm XR4000, and so on. The codes (GA4100, TB4025, PL4025) stay the same.
- GA4000 is the general-purpose PIR board (50–100mm). XR4000 is the thicker board (120mm and up). TB4000 is the thin board (20–40mm) for reveals and overlays. PL4000 is insulated plasterboard.
- GA4000, XR4000 and TB4000 all declare λ 0.022 W/mK according to Soprema's datasheets, and we sell them by the single sheet.
What's changed with the Sopratherm rebrand?
The boards are still PIR foam with low-emissivity composite foil facings on both sides, still 2400 × 1200mm and still use the same product codes. The datasheets, declarations of performance and BBA certificates are now issued under the Sopratherm name. You'll also see the name searched for as "Sopretherm" or "Supertherm". If your drawings or a merchant's quote say Celotex GA4100, Sopratherm GA4100 is the board you need.
The Celotex range explained
| Range | What it's for | Thicknesses we stock | Key data (Soprema datasheets) |
|---|---|---|---|
| GA4000 | General purpose: pitched roofs (between and under rafters), floors, internal and external walls | 50, 60, 70, 75, 80, 90, 100mm | λ 0.022 W/mK; 100mm R 4.50 m²K/W; compressive strength ≥140 kPa |
| XR4000 | Thicker boards for pitched roofs, floors and walls where you need a low U-value from one layer | 120, 150mm | λ 0.022 W/mK; 120mm R 5.45 m²K/W |
| TB4000 | Thin boards for window and door reveals (thermal bridging), insulated dry lining and overlaying existing insulation | 20, 25, 30, 40mm | λ 0.022 W/mK; 25mm R 1.10 m²K/W |
| PL4000 | Insulated plasterboard: PIR bonded to 12.5mm tapered-edge plasterboard, for lining walls | 37.5, 52.5, 62.5, 77.5mm total | 37.5mm (PL4025) R 1.20 m²K/W; Euroclass B-s1,d0 |
Prices
Prices are per 2400 × 1200mm sheet (2.88m²), ex VAT, at the time of writing.
| Board | Thickness | Price per sheet | Per m² |
|---|---|---|---|
| TB4025 | 25mm | £13.61 | £4.73 |
| TB4040 | 40mm | £19.86 | £6.90 |
| GA4050 | 50mm | £21.03 | £7.30 |
| GA4075 | 75mm | £28.36 | £9.85 |
| GA4100 | 100mm | £34.65 | £12.03 |
| XR4120 | 120mm | £43.07 | £14.95 |
| XR4150 | 150mm | £51.88 | £18.01 |
| PL4025 | 37.5mm | £37.66 | £13.08 |
| PL4050 | 62.5mm | £50.54 | £17.55 |
The other thicknesses (20, 30, 60, 70, 80 and 90mm, and PL4040 and PL4065) are in our Celotex range.
Which Celotex board do I need?
- Pitched roof, between rafters: GA4000 sized to the rafter depth (leaving any ventilation gap the design needs), often with PL4000 underneath. Check it with our PIR U-value calculator.
- Floors: GA4000 or XR4000 under a screed or chipboard deck. See PIR vs EPS vs XPS floor insulation.
- Window reveals and topping up: TB4000.
- Lining a solid wall: PL4000 insulated plasterboard. See how to install insulated plasterboard.
For thickness by element, read what thickness of PIR insulation do I need.
Cutting and fitting tips
- Cut cleanly. A fine-toothed saw or a long, sharp insulation knife gives a tight fit between rafters and joists. See how to cut PIR insulation board.
- Fit tightly. Gaps around boards let heat bypass the insulation. Fill small gaps with expanding foam.
- Tape the joints. Taping the foil-faced joints with foil tape (£4.16 a roll) helps airtightness, and the foil facing then acts as a vapour control layer. See breather membrane vs vapour control layer.
- Store boards flat and dry. Keep them off the ground and covered until you fit them.
Celotex vs other PIR brands
Celotex GA4000, Kingspan Thermapitch TP10, Recticel Eurothane GP and Mannok PIR all declare λ 0.022 W/mK, so a 100mm board gives R 4.50 m²K/W whichever you choose. The differences are price, availability and which brand your specification names. See our PIR brand comparison and our Kingspan buying guide.
Frequently asked questions
Is Celotex still being made?
Yes, under the Sopratherm name. Soprema makes the boards with the same product codes.
Is Sopratherm GA4000 the same as Celotex GA4000?
It's the same range under a new name: a PIR board with foil facings, λ 0.022 W/mK, 2400 × 1200mm. Use Soprema's current datasheet for any specification work.
Can I buy a single sheet?
Yes. All our Celotex/Sopratherm boards are priced and sold per sheet.
Is Celotex fire rated?
GA4000, XR4000 and TB4000 boards are Euroclass F for reaction to fire on their own, like most foil-faced PIR. PL4000 insulated plasterboard is B-s1,d0. Fire performance in use depends on the whole construction.
Buy Celotex insulation online
Browse the full Celotex range or all PIR insulation boards. Prices are shown ex VAT. We are delivery only (no collection) and deliver to mainland England. Insulation, plasterboard and drylining orders have a £400 ex VAT minimum and free delivery (see delivery information). Celotex (Sopratherm) is delivered separately: £400 ex VAT minimum, £40 ex VAT delivery under £550 ex VAT, free from £550 ex VAT. Call us on 03330 908479 (Mon–Thu 8am–5pm, Fri 8am–12pm), email sales@insulationwarehousedirect.co.uk, or order online.
Sources: Soprema datasheets for Sopratherm GA4000, XR4000, TB4000 and PL4000. Figures are indicative and correct at the time of writing.