PIR Insulation Price per m² by Thickness (25–150mm)

PIR boards are priced per sheet, but you work out the job per square metre. A standard 2400 × 1200mm board covers 2.88 m², so dividing the sheet price by 2.88 gives a price per m² you can compare between thicknesses and brands. This guide lists the general-purpose PIR boards we sell today, with the price per board and the price per m², all ex VAT.

Prices correct at 28 October 2026 and may change. All prices are ex VAT; check the product page for the current price.

Quick answer

• Our general-purpose PIR boards run from about £4.73 per m² ex VAT for 25mm to about £18.01 per m² ex VAT for 150mm, taking the lowest-priced board at each thickness. We list 125mm in Kingspan only, so there is no other brand to compare at that thickness.
• Every board in the table is 2400 × 1200mm (2.88 m²) and is sold per sheet. Flat roof boards are sold in packs and are covered in our flat roof PIR guide.
• The boards listed here show a thermal conductivity (λ) of 0.022 W/mK on their product pages. At the same thickness they should give the same thermal resistance, so price per m² is a fair way to compare them.
• Price per m² does not rise in a perfectly straight line with thickness, so always compare the actual boards on the day you order.

PIR insulation price per m² by thickness

Each cell shows the price per sheet, linked to the product page, with the price per m² underneath (sheet price ÷ 2.88). All prices ex VAT. Prices correct at 28 October 2026 and may change.

For example, 25mm Recticel Eurothane GP is £13.61 ex VAT a sheet, which is £13.61 ÷ 2.88 = £4.73 per m². The 150mm Kingspan Thermapitch TP10 is £78.28 ex VAT a sheet, or £27.18 per m².

The pattern is not perfectly smooth. In the Kingspan range the 125mm board is currently £82.66 ex VAT and the 150mm board £78.28 ex VAT, so the thicker board is the cheaper one per sheet. We show the prices as they are listed. Compare the boards on the product pages rather than assuming a thicker board always costs more. Some thicknesses are not made by every brand, which is why some cells are blank. The 20mm board is Celotex TB4000, and Celotex GA4000 now carries the Sopratherm name on the board.

How many boards do you need?

1. Work out the area to insulate in m² (length × width, less any openings).
2. Divide by 2.88 to get the number of full boards.
3. Add about 10% for cuts and offcuts, then round up to a whole board.

Worked example: for 24 m² of floor, 24 ÷ 2.88 = 8.33 boards. Add 10% and you get 9.17, so order 10 boards. At 100mm, using the Recticel Eurothane GP 100mm at £36.83 ex VAT, that is 10 × £36.83 = £368.30 ex VAT for the boards, before delivery.

Our insulation calculator does this for you, and the PIR U-value calculator helps you choose a thickness.

Choosing a thickness

Thermal resistance (R-value) is thickness in metres divided by λ. At λ 0.022 W/mK that gives about 4.5 m²K/W for 100mm, 5.45 for 120mm and 6.8 for 150mm, which are the figures shown on our product pages (rounded down). Thinner boards cost less per m², but the right thickness is the one that meets the U-value for your floor, wall or roof, which depends on the whole construction. Check the manufacturer’s datasheet for your board, and confirm the specification with your building control body or designer. For roofs, see our guides to flat roof PIR thickness and PIR in the loft.

Frequently asked questions

Is PIR insulation priced per sheet or per m²?

Our general-purpose boards are priced per 2400 × 1200mm sheet. Divide the sheet price by 2.88 to get the price per m². Flat roof and cavity boards are sold in packs, so check the pack size in the title.

Does a cheaper board per m² insulate less?

Not if the thickness and λ are the same. The general-purpose boards in the table all show λ 0.022 W/mK on their product pages, so a 100mm board from any of them gives about the same thermal resistance. Check the datasheet and the facings for your use.

Do the prices include VAT or delivery?

No. Prices are ex VAT and delivery is not included in the figures above. Most orders over £400 + VAT are delivered free across England, with delivery to mainland Wales and Scotland too. Mainland Wales and mainland Scotland: Celotex insulation and Knauf loft roll have £40 ex VAT delivery on every order; ceilings have a £400 ex VAT minimum plus £40 ex VAT delivery; British Gypsum plaster and plasterboard have a £400 ex VAT minimum plus £40 ex VAT delivery. We do not deliver to Northern Ireland or the Scottish islands.; see our delivery policy for the details.

Order PIR insulation boards

Browse our PIR insulation boards or the floor insulation boards. Prices are shown ex VAT. If you are not sure which board suits your job, call us on 03330 908479 (Mon–Thu 8am–5pm, Fri 8am–12pm) or email sales@insulationwarehousedirect.co.uk and we will help you choose.

Sources: prices, sizes and λ values from our live PIR insulation collection; R-values as Recticel Eurothane GP datasheet.