Celotex TB4000 PIR Insulation Boards

A thermal bridge is a weak link in the outer shell of your home; threatening heat loss and structural woes such as condensation and mould growth. Celotex TB4000 delivers maximum efficiency in overcoming thermal bridging and can be considered for floor, wall, and roof applications. 

The 2.4m x 1.2m boards have low global warming potential (GWP) and showcase low-emissivity foil facings on either side, with a thermal conductivity of just 0.022 W/m.K.

    close

    Product filters

    • Manufacturer

      keyboard_arrow_right
    • Thermal conductivity

      keyboard_arrow_right
    • Width

      keyboard_arrow_right
    • Thickness

      keyboard_arrow_right
    • Material type

      keyboard_arrow_right

£26.34
inc VAT

Want a quotation?


£20.70
inc VAT

Want a quotation?


£22.79
inc VAT

Want a quotation?

Celotex TB4000 PIR Applications

Specifically designed to eliminate thermal bridges, (as the 'TB' in its title states), TB4000 multi-purpose insulation board is suitable for numerous applications such as roofs, floors and walls. The 1200mm x 2400mm boards give improved thermal insulation performance within cavity air spaces with a thermal conductivity of just 0.022 W/m.K, improving the achievable U-value. 

Celotex boards reduce the thickness of insulation required to hit the target U-Value. Available in thicknesses from 20mm to 40mm, it can be considered for floor, wall, and roof applications.


Celotex TB4000 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
  • Pitched Roof - Below Timber Rafters
  • Pitched Roof - Above Timber Rafters


Celotex TB4000 Key Features


Celotex TB4000 Insulation is an easy-to-install polyisocyanurate (PIR) insulation board with excellent thermal performance, featuring a low emissivity foil facing. The high performance 2.4m x 1.2m boards are manufactured with specially designed blowing agents that have zero ozone depletion potential (ODP) and low global warming potential (GWP). 

Let's have a look at the specs:

  • Excellent thermal performance with a thermal conductivity of 0.022 W/m.K
  • Low Global Warming Potential (GWP) and Zero ODP
  • Easy to install
  • Improved thermal performance in sealed cavity air spaces
  • Light and rigid, assisting with ease of transportation, handling and fitting
  • Provides reliable long-term energy savings for buildings
  • BBA certified - Celotex TB4000 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
  • Lightweight 2400 x 1200mm boards


Celotex Fire Classification


Celotex TB4000 PIR is tested to BS EN 13501-1 with a classification of E. Simply put, this means it is combustible and will contribute to the overall fire load. Because of this, the boards must not be used in the external facades of buildings over 18m in height in England and Wales or over 11m in height in Scotland.

When using Celotex TB4000 PIR insulation board, please satisfy your installation meets all relevant national Building Regulations and guidance and local, national and other applicable standards relevant to your construction or application.

Celotex Thicknesses


It might seem like identical Celotex boards have different codes on our website. The most popular Celotex PIR general application insulation board in our range is 2400mm long and 1200mm wide.

You might see products labelled Celotex TB4040, Celotex TB4030, and Celotex TB4020. All these products have the same dimensions in terms of length and width. The only difference between these boards is that they each have different thicknesses.


Different codes represent different thicknesses. We stock a sliding scale of boards that suit every situation from thinner solutions starting at 20mm thick, all the way up to 150mm thick boards. And if that's not enough, you can always consider using two-layer build-ups.

Follow our handy Celotex thickness guide to find a PIR insulation board that suits your project.

●     Celotex TB4000 - 20mm, 25mm, 30mm, and 40mm thickness

For further details on all of the Celotex ranges, please refer to our Celotex page. Here, you can expect to find full details on each individual range.