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16 Reviews

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25mm Celotex TB4025 PIR Insulation Board 2400mm x 1200mm

URN: 3001024
Core
£10.68ex. VAT £3.71 per m2 Get it for £9.96 ex. VAT with CORE+
£10.68ex. VAT
£3.71 per m2
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Coverage required
m
m
Based on your total area of m2 (inc. 10% wastage) - of these are required (actual coverage of m2)

We recommend purchasing at least 10% extra product to allow for errors, damages or obstacles

PIR insulation board with foil facings, designed to combat thermal bridging. Suitable for floors, walls, and roofs. 25mm sheet improves insulation while fitting within shallow voids and tight cavities.

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Mon 22 Sep

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Product Overview

PIR insulation board with foil facings, designed to combat thermal bridging. Suitable for floors, walls, and roofs. 25mm sheet improves insulation while fitting within shallow voids and tight cavities.

URN: 3001024
£10.68ex. VAT

Delivery & Returns Information

How Our Delivery Works

We work with a nationwide network of trusted suppliers. As a result, items in your basket may be supplied by different suppliers and delivered separately. Where this applies, you'll see multiple delivery charges at checkout. We always aim to group products from the same supplier to keep delivery costs as low as possible.

Delivery Areas & Charges

Delivery charges listed on our website apply to mainland UK, excluding the following postcode areas: AB, CF, DD, DG, FK, KW, IV, LA, LD, LL, NP, PA, PH, SA, SY
If your delivery address falls within one of these postcode areas, we’ll be in touch before processing your order to confirm any additional delivery costs.
Please note: We do not currently offer delivery outside the UK mainland.

Standard (Nationwide) Delivery

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Core
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Under £300 ex. VAT £20 ex. VAT
Over £300 ex. VAT FREE

Core Delivery charges apply only when all products in an order that have equivalents are accepted as such. If even one product cannot be substituted with an equivalent, the entire order will not qualify for Core Delivery charges.

Insulation, Plasterboard and Drylining Products
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Over £350 ex. VAT FREE
Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products
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Under £100 £15 ex. VAT
Between £100 - £300 ex. VAT £10 ex. VAT
Over £300 ex. VAT FREE
Screws & Fixings and Adhesives & Sealants
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Under £50 £5 ex. VAT
Over £50 ex. VAT FREE

Express Delivery

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

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Returns

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
Thickness:25mm
Width:1200mm
Length:2400mm
Sales Unit:Board
Sales Unit Coverage:2.88m2
Brand:Celotex
Manufacturer's Reference:TB4025
Weight:2.74kg
Thermal Conductivity:0.022W/mK

Product Overview

Foil-faced PIR insulation board for use in floors, walls, and roofs. 

Part of the TB4000 range, it is used to limit thermal bridging at reveals, junctions, and edges where insulation layers are interrupted. 

At 25mm thick, this board fits shallow cavities and tight voids while bolstering thermal performance.

Features & Benefits

  • Thermal conductivity (0.022 W/m·K): Reduces the thickness required to meet U-value targets.
  • Low-emissivity foil facings: Reflect radiant heat across unventilated air gaps, cutting thermal transfer at junctions.
  • TB4000 range (thermal bridging control): Improves continuity of insulation where up to 30% of fabric heat loss can otherwise occur.
  • Rigid PIR core: Lightweight yet robust, easy to cut and install with standard tools.
  • Moisture resistance: Closed-cell core prevents water uptake and preserves thermal performance.
  • Environmental credentials: Zero ODP, low GWP blowing agent, and BRE Green Guide Rating A.
  • BBA certified (17/5405, 16/5352): Independent assurance of performance across roofs, walls, and floors.
  • Board size 2400 x 1200mm: Large-format sheets reduce installation time.
  • Thickness 25mm: Suited to shallow voids and cavities while upgrading insulation.

Applications

  • Thermal bridging details (reveals, lintels, junctions): Limits cold spots, condensation risk, and heat loss where insulation layers are interrupted.
  • Roofs (pitched/flat): Useful for upgrades at rafter lines, perimeter upstands, or overlaying to reduce bridging.
  • Walls (timber frame/masonry): Applied at reveals, edges, or internally to improve continuity.
  • Floors (beam & block, slab, timber): Commonly used as perimeter upstand insulation or for targeted slab upgrades.


Installation Guidance

  • Cut and fit tightly: Use a knife or fine-tooth saw; maintain close joints to avoid thermal bypass.
  • Seal or tape as specified: Ensures continuity with air and vapour control layers.
  • Protect on site: Store boards flat, dry, and covered until required.

Compliance & Performance

  • Thermal conductivity: 0.022 W/m·K (BS EN 12667).
  • Compressive strength: ≥140 kPa (BS EN 826).
  • Reaction to fire: Euroclass E (BS EN 13501-1).
  • Environmental performance: Zero ODP, low GWP, BRE Green Guide Rating A.



Customer Reviews

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4
3
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5/5 based on 16 reviews

Used this to better insulate my outer house walls ahead of next winter

Luke Plower on

came on time and the driver was really kind

Sammy Giles on

Good service and insulation

Gary Wills on

Good quality insulation

Ian Norris on

The delivery was prompt and the product is good value for money.

Juliana Marković on

Thank you for a good service and product

Roberto Munez on

Arrive on time, thanks

Piotr Kavek on

Easy to cut and easy to install under my floor between the joists. The price and service were excellent too.

Liam Jones on

Great insulation, bought 50mm and 100mm also at a competitive price.

Martin Chivers on

Used this to reduce thermal bridging around columns and worked a charm! Very good price too!

Craig Williams on

Really cheap and I had the boards delivered in 2 working days, thank you

Ava B on

I was recommended this thermal insulation from a friend because it was simple to cut and install

Lucas Cummins on

grand

Donald Gray on

good insulation

Mo Croft on

reduces thermal bridging

Andy Chivers on

great

Gregor Zygoras on

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