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

URN: 3001024 In Stock
£14.30ex. VAT £4.97 per m2
£14.30ex. VAT
£4.97 per m2
Bulk Discount
35+ boards 70+ boards 110+ boards
£14.16ex. VAT £14.01ex. VAT £13.87ex. VAT
Celotex TB4025 is a high-performance thermal insulation PIR board with composite foil facings. It can be used for roof, floor, wall and timber joist applications.

Express Delivery


Standard Delivery

Wed 29 Mar

Product Overview

Celotex TB4025 is a high-performance thermal insulation PIR board with composite foil facings. It can be used for roof, floor, wall and timber joist applications.

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

URN: 3001024
£14.30ex. VAT

Delivery & Returns Information

All delivery charges are shown in your basket and are dependent on the total value of items in your basket based on product category.

Standard (Nationwide) Delivery

Insulation, Plasterboard and Drylining
Under £150 ex. VAT £75 ex. VAT
Between £150 - £300 ex. VAT £50 ex. VAT
Between £300 - £500 ex. VAT £25 ex. VAT
Over £500 ex. VAT FREE
Building Material Products
Under £300 ex. VAT £50 ex. VAT
Between £300 – £500 ex. VAT £25 ex. VAT
Over £500 ex. VAT FREE
Under £100 ex. VAT £7.50 ex. VAT
Over £100 ex. VAT FREE
SuperFOIL and YBS products
Each item £10 ex. VAT
Over £350 ex. VAT of 1 brand FREE

Express Delivery

Under £300 ex. VAT £75 ex. VAT
Over £300 ex. VAT £50 ex. VAT

This charge is based on delivery to mainland UK excluding the Scottish Highlands. If your delivery address is in the Scottish Highlands a member of our customer service team will contact you prior to processing your order should an additional delivery charge apply. We do not offer deliveries outside the UK mainland.

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We offer a 30 day returns policy on any faulty products.

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Key Features

  • Use in floors, framed walls and pitched roofs
  • Aluminium composite facing on both sides
  • 0.022 W/mK thermal conductivity
  • Easy to handle and install
  • Zero Ozone Depletion Potential (ODP)
  • BBA certified
  • 140kPA compressive strength
  • 150MN.s/g.m Surface Spread of Flame

Technical Specification

Technical Specification
Material Type:PIR
Sales Unit:Board
Sales Unit Coverage:2.88m2
Manufacturer's Reference:TB4025
Thermal Conductivity:0.022W/mK

Product Description

Thermal bridges aren't only an issue of heat loss and the higher bills that come with them, they also greatly impact your comfort and quality of life. Celotex TB4025 PIR Insulation 25mm is a BBA-certified thermal insulation solution purposed to combat thermal-bridging in a variety of floor, wall and roof applications. The 2.4m x 1.2m boards are manufactured using a blend of specially designed blowing agents that have zero ozone depletion potential (ODP) and low global warming potential (GWP). Not only do they promise environmental kindness but TB4025 boards also bring in maximum thermal efficiency with thermal conductivity of just 0.022 W/m.K.

25mm Celotex PIR boards have their low emissivity foil facings to thank for this low number and hence, do a wonderful job of improving thermal conductivity in sealed cavity air spaces. Celotex TB4025 is also equipped with a BRE Green Guide rating A, which can be used in your BREEAM assessments to show environmental performance.

TB4025 Celotex 25mm PIR Insulation Board Applications

Specifically designed to eliminate thermal bridges, (as the 'TB' in its title states), TB4025 is suitable for roof, floor, and wall applications in new buildings or refurbishment projects. 

With a thermal conductivity of 0.022w W/mK, TB4025 is the ideal solution for insulation in pitched roofs, flat roofs, solid masonry walls, timber frames, and steel framed systems. 

It can also be used in solid floor systems such as screed and concrete slab floors, and as loft insulation between timber rafters. 

Celotex TB4025 can be used in the following construction types:

  • Ground Floor - Concrete Slab (perimeter upstand)
  • Ground Floor - Beam and Block (perimeter upstand)
  • Ground Floor - Suspended Timber Joists (perimeter upstand)
  • Ground Floor - Upgrading Existing Concrete Slab (perimeter upstand)
  • External Wall - Timber Frame Internal Linings
  • External Wall - Masonry Cavity Internal Linings
  • External Wall - Solid Masonry Internal Linings
  • Partition Wall
  • Pitched Roof - Below Timber Rafters
  • Pitched Roof - Above Timber Rafters

Celotex TB4025 Specifications

Celotex TB4025 board comprises a fibre-free rigid polyisocyanurate (PIR) insulation core faced with an aluminium foil composite on both sides.

Celotex TB4025 insulation board is one of the thinnest PIR insulation sizes available and is particularly effective at overcoming thermal bridging.

Celotex 25mm TB4025 boards eliminate thermal bridges by providing a continuous layer of rigid polyisocyanurate PIR insulation within the building structure, providing long-term energy savings.

The board's PIR core is manufactured using blowing agents with zero ODP and low GWP, rendering it an ecologically friendly option. 

Let's have a look at the specs:

  • Excellent thermal conductivity of 0.022w W/mK -  reduces the thickness required to hit the target U-value
  • Low emissivity foil facing provides improved thermal performance in sealed cavity air spaces
  • Complies with UK Building Regulations with better U-values and thinner solutions
  • Zero Global Warming Potential (GWP) and Zero Ozone Depleting Potential (ODP)
  • Easy to install
  • BBA certified - Celotex TB4025 has been assessed by the BBA as fit for use in defined roof, wall and floor applications if installed, used and maintained as set out in the certificate
  • Achieves a BRE Green Guide Rating of A, which can assist in demonstrating environmental performance in your BREEAM assessments
  • Standard board size: 1200mm x 2400mm
  • Water vapour resistance: 150MN.s/g.m

Celotex TB4025 Insulation Board Certifications

BS EN is British and European Standard Specifications. With over 100 years of experience, the British Standards Institute is recognised as the UK’s National standards body.

  • Spread of flame: Euroclass E Reaction to Fire classification, according to BS EN 13501-1
  • Compressive Strength: 140kPa
  • Thermal conductivity of 0.022 W/m.K, reducing the thickness of insulation required to hit the target U-value - BS EN 12667
  • BRE Green Guide Rating of A for sustainability - which can assist in demonstrating environmental performance in your BREEAM assessments
  • BBA certified

25mm Celotex TB4025 Insulation Storage & Handling

As they are super light and portable, 25mm Celotex TB4025 boards can also be handled and transported easily.

If you need to store 25mm TB4025 Celotex insulation boards for a while before installation, you should choose a cool, dry space.

Our rule of thumb when it comes to storage is that the boards should not be stored on the ground. Instead, store them on a level surface and under a protective cover.

About Celotex

Celotex is a leading British manufacturer of 25mm TB4000 PIR insulation. Founded in the early 1920s, the company has since evolved from a fibreboard insulation company to one that solely focuses on PIR insulation boards that offer excellent thermal performance.

The TB4025 insulation board is just one of many popular thermal insulation solutions in the Celotex product range. The Celotex TB4000 PIR insulation range consists of thicknesses: 20mm, 25mm, 30mm, and 40mm, all of which are available for prompt delivery at a competitive price on our site.


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


Donald Gray on

good insulation

Mo Croft on

reduces thermal bridging

Andy Chivers on


Gregor Zygoras on

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