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IMPORTANT: CLICK FOR PIR PRODUCT AVAILABILITY INFORMATION

Celotex TB4000 Thermal Break Rigid PIR, plus NEW! Celotex US4025 Floor Upstand Rigid PIR Boards

Standard Celotex Product, generally readily available in most thickness’s

Product Functions Celotex TB4000 installed in a wooden stud partition wall application

The Celotex TB4000 Range Is multi-purpose insulation board developed to provide simple solutions for overcoming localised thermal bridging. It is eminently suitable for a number of applications including roof, wall and floor insulation.

These thermal bridging boards is specifically designed to eliminate thermal bridges, and is easy to cut and shape are commonly used in conjunction with appropriate internal lining boards, to improve the thermal insulation of existing and new, pitched roofs, solid or cavity masonry walls, or timber-frame walls, and floor up-stand insulation.

The TB4000 range is unique in being able to offer boards as thin as 12 mm to the market for this purpose.

These products have similar characteristics to the GA4000 range but with un-reinforced core foam..

Common applications include the creation of thermal barriers for virtually any element of a building where thermal bridging issues need to be addressed, such as Pitched roofs, Flat roofs, Solid masonry walls, Timber framed & steel framed systems, and Floors and Floor Up-stands.

Product Description

TB4000 is a multi-purpose rigid polyisocyanurate foam (PIR) thermal insulation board with reflective foil facings. provides multi-purpose cavity wall insulation boards that are uniquely reinforced with glass-fibre and feature strong reaction-to-fire performance when measured in accordance with new European Standards.

Celotex T-Break TB4000 is installed in conjunction with an appropriate lining panel, for example standard gypsum plasterboard to BS 1230-1 : 1985.

These boards include low emissivity foil facings giving improved thermal insulation with cavity air spaces, providing reliable long-term energy savings for building applications.

These insulation boards are available in nominal dimensions of length (mm) 2400 x width (mm) 1200, and come in thickness’s ranging from 12-45mm, making it the thinnest PIR insulation available ... suitable for use in a number of applications including roof, wall and floor systems.

This multi-purpose PIR insulation board has long been at the heart of Celotex product range and achieves an A+ rating when compared to the BRE Green Guide.

Board size: 1200 x 2400mm, Thickness's 12-45mm, with a Lambda value of 0.022 W/mK

Product Benefits

Celotex is also commonly being used in conjunction with complementary rigid board insulation, as well as

being used with dry-lining boards, or insulated plasterboards such as Knauf Thermal Laminate or Gyproc ThermaLine, and to improve the thermal insulation of existing and new, solid or cavity masonry walls and timber-frame walls. It is also enhances the performance of reflective barriers such as YBS SuperQuilt, Superfoil SF19 and SF40, TLX Gold, TLX Silver , Gen-X, or Triso Super 10

TB4000 may also be used in locations where the insulated surface is inaccessible, such as existing ceilings of flat roofs.

Offers high performance insulation with low emissivity foil facings offering enhanced thermal performance within cavity air spaces

Is certified under BBA certificate number 95/3197 and 09/4667

Is suitable for a number of applications including roof, wall and floor systems

Has low global warming potential (GWP) and zero ozone depletion potential (ODP)

Future proofs the energy performance of new and existing buildings


Product availability indicators

TB4000 - Price and Availability Advisory:

Presently there are no availability restrictions.

Excellent = Product Availability Excellent  Good = Product Availability Good  Fair = Product Availability Fair  Poor =  Product Availability Poor  Undetermined = Product Availability Undetermined
Availability relies on stock levels at closest depots and upon transport logistics to effect deliveries


Technical Data



Celotex TB4000 Thermal Bridging Rigid PIR Insulation Boards

Product Code

Board dimensions

Thickness (mm)

λ Value (w/mK)

R-value (m²K/W)

U Value (W/m²K)

Weight (kg/m²)

Single Board weight (kg)

Celotex TB4012 1.2 x 2.4 = 2.88m² 12 0.022 0.50 2.00 0.50 1.44
Celotex TB4020 1.2 x 2.4 = 2.88m² 20 0.022 0.90 1.11 0.72 2.07
Celotex TB4025 1.2 x 2.4 = 2.88m² 25 0.022 1.10 0.91 0.85 2.45
Celotex TB4030 1.2 x 2.4 = 2.88m² 30 0.022 1.35 0.74 0.98 2.82
Celotex TB4035 1.2 x 2.4 = 2.88m² 35 0.022 1.55 0.65 1.11 3.20
Celotex TB4040 1.2 x 2.4 = 2.88m² 40 0.022 1.80 0.56 1.26 3.63
Celotex TB4045 1.2 x 2.4 = 2.88m² 45 0.022 2.00 0.50 1.40 4.03

Thermal conductivity / Lambda value (W/mK) = 0.022 | Compressive strength (kPa) = ≥ 120 | Water vapour resistance (MNs/g) = > 150 | Please Note: R-Value = Thermal Resistance; U Value = Thermal Transmittance Co-efficient; Compressive strength = kiloPascals; Vapour resistance = MegaNewton seconds per gram.

Celotex US4025 Floor Upstand Rigid PIR Insulation Boards

Product Code

Board dimensions
(16 boards per pack)

Thickness (mm)

λ Value (w/mK)

R-value (m²K/W)

U Value (W/m²K)

Weight (kg/m²)

16 Board weight (kg)

Celotex TB4025 16 x 1.2 x 2.4 = 46.08m² 25 0.022 1.10 0.91 0.73 33.64

New from Celotex ...
US4025 Upstand Insulation for concrete slab and beam & block flooring applications. More information to follow.

Product Information and Certification

Links to manufacturer's information. Click to download in a separate browser window.


  • Celotex GA & XR ranges

    Celotex GA4000 and XR4000 branding is used to differentiate between boards thicker and more robust than the TB4000 range.

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    Celotex Ga4000 and XR4000 General Application Boards
  • Celotex CW4000

    Celotex Cavity Wall boards are cut-down (0.45 x 1.2m) versions of the TB4000, GA4000 & XR4000 general application boards.

    View Full Detail

    Celotex CW4000 Rigid PIR Cavity Wall Boards
  • Kingspan TP10 / TF70

    Kingspan TP10 & TF73 are identical boards, branded to emphasise their suitability for roof and floor applications

    View Full Detail

    Kingspan TP10 and TF73 are general application boards suitable for roof and floor applications
  • Kingspan TW50

    Kingspan ThermaWall TW50 is a cut-down (0.45 x 1.2m) version of the TP10, TF70 & TW55, general application boards.

    View Full Detail

    Kingspan TW50 is a cut-down (0.45 x 1.2m) version of TP10, TF70 and TW55

Product Installation

Celotex TB4000 thermal break installation examples

Pitched roof with Sarking

The void created by a pitched roof can be made habitable by insulating along the plane of the roof pitch with Celotex rigid PIR insulation boards. This creates a warm, potentially habitable roof space in which water pipes and tanks no longer need to be insulated.

When used over the roof structure as insulating sarking, Celotex insulation creates a warm roof structure and eliminates thermal bridging at the rafters, whilst the foil facings, used in conjunction with taped joints, provide an effective barrier to moisture vapour and air leakage.

The use of a single continuous layer of insulation over the rafters thereby eliminates the risk of condensation and avoids the need for ventilation of the rafter space. Where very low U Values are required Celotex recommends a two-layer system in order to reduce the racking forces on the fasteners required to fix counter- battens to rafters.
In this system, the first layer of insulation is applied as a complete layer over the rafters. A second, thinner layer is then fitted over the first layer, between the counter-battens.


Insulation between and over rafters

Cetotex TB4000, GA4000 and XR4000, are ideally suited for between and over rafters installation in pitched roof applications

Where headroom and rafter depth is limited, Celotex insulation may be fitted between and over the rafters.

The void created by a pitched roof can be made habitable by insulating along the plane of the roof pitch with Celotex rigid PIR insulation boards. This creates a warm, potentially habitable, roof space in which water pipes and tanks no longer need to be insulated.

Where headroom and rafter depth is limited, Celotex insulation may be fitted between and over the rafters. If this two-layer solution is chosen, it is important that the thermal resistance of the inner layer (between the rafters), is less than that of the outer layer (over the rafters).This reduces the risk of interstitial condensation between the insulation layers.

The condensation risk also depends upon occupancy and building use. Celotex recommends that a condensation risk analysis is obtained to determine the optimum solution for your project.


Insulation between and under rafters

Ideally suited for between and under rafters installation in pitched roof applications are Cetotex TB4000, GA4000 and XR4000

The void created by a pitched roof can be made habitable by insulating along the plane of the roof pitch with Celotex rigid PIR insulation boards. This creates a warm, potentially habitable roof space in which water pipes and tanks no longer need to be insulated.

If sarking felt is being used, a minimum 50 mm ventilated air space must be provided between the felt and the cold side of the insulation in order to minimise the risk of condensation formation. This is known as ventilated construction.

With some breathable membranes, the cold side of the insulation may be placed in direct contact with the membrane (check with membrane supplier prior to specification).

However, the outer side of the membrane must be adjacent to an air space to allow moisture vapour to escape to the outside of the building, which is known as an unventilated construction.


Celotex TB4000, GA4000 and XR4000 inhibit thermal bridging in metal stud wallapplicationsSteel stud framed wall insulation

Historically, the use of steel framed walls has been found mostly in the construction of commercial buildings. However, the recent growth in Modern Methods of Construction (MMC) has seen an increase in the popularity of lightweight steel framed buildings for both commercial and residential developments.
The off-site pre-fabrication of framed panels allows rapid, accurate construction on site. To minimise building heat losses, rigid thermal insulation is placed on the outside of the frame as a continuous layer to eliminate thermal bridging through the metal studs. This is known as 'warm frame' construction.
The very low thermal conductivity of Celotex Tuff-R GA4000 enables high levels of insulation to be achieved with minimal overall thickness.


Beam & block floor insulation

Beam and block floors can be insulated simply by laying Celotex Insulation boards over the floor before applying a screed or board finish.
The specification of insulation for ground floors is more complex than that for walls or roofs. This is because the mechanisms for heat flow are affected by the ratio of surface area to perimeter. With a beam and block floor, there is little choice but to install the insulation over the floor before screeding.
The ventilated air space beneath any suspended floor can be very cold, so Celotex recommends the application of a continuous vapour - control membrane over the top of the insulation, before screeding, to reduce the risk of condensation forming at the insulation/slab


Contact Manufacturer

Celotex Limited

Lady Lane Industrial Estate, Hadleigh, Ipswich, Suffolk, IP7 6BA

Celotex Technical Advisory Service.

Telephone: 0901 996 0100 (30p per minute) - Fax: 01473 820 889
Email: technical@celotex.co.uk
Web sites: Celotex Home Page / Celotex U-Value Calculator.

Contact us

Insulation Online Limited

27 Massetts Road, Horley, Surrey, RH6 7DQ, UK

Telephone: 0333 8000 828

Facsimile: 0333 7000 797

Email: enquiries@insulation-online.com

Web site: www.insulation-online.com

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