Slim PIR Insulation Board for Thermal Bridging, Walls, Floors and Roofs

Celotex TB4000 is a slim, high-performance PIR insulation board designed for projects where space is restricted but thermal performance still matters. It is commonly used to reduce thermal bridging around walls, floors, roofs, reveals, junctions and other areas where thicker insulation boards may not be practical.

Each board measures 2400mm x 1200mm and covers 2.88m². The TB4000 range is available in thinner board options, including 20mm, 25mm, 30mm and 40mm, making it useful for detail work, internal upgrades and areas with limited build-up depth.

Celotex TB4000 has a rigid PIR insulation core with low-emissivity foil facings on both sides. It provides a thermal conductivity of 0.022 W/mK, helping improve energy efficiency while keeping the insulation layer slim and easy to install.

Why Choose This Product?

Choose this as a practical rigid insulation board for straightforward wall, floor or pitched-roof work. PIR gives strong thermal resistance without the depth required by most mineral wool products.

Key Features

·        20mm to 40mm PIR

·        2400 x 1200mm

·        Declared conductivity: 0.022 W/mK

·        Straight edges and foil facings

Common Uses

·        Thermal bridging strips

·        Internal wall linings

·        Roof and floor details

Installation

Cut boards or rolls accurately, close every joint and keep the insulation layer continuous at corners, openings and service penetrations. Use the fixings, tapes, membranes and covering layers stated for the selected construction.

Before You Install

·        Leaving narrow gaps between boards.

·        Assuming foil tape repairs large or badly cut joints.

·        Using a general-purpose board in a cavity or flat-roof application without approval.

·        Calculating quantity from pack size instead of board coverage.

Frequently Asked Questions

Is this the same as Kingspan?

It is the same broad insulation type where both products are foil-faced PIR with the same declared lambda, but approvals, facings, dimensions and application documents can differ.

Can it be used between rafters?

Yes where the product certification covers pitched roofs. Cut tightly and maintain any required ventilation path.

Can it go under a screed?

Only where the floor construction and product documentation permit it.

Should foil joints be taped?

Tape joints where the foil facing forms part of the air or vapour-control layer.

How much does one board cover?

A 2400 x 1200mm board covers 2.88m².

What You'll Need

·        Foil insulation tape

·        Low-expansion insulation foam

·        Insulation fixings

·        PIR cutting saw

·        Vapour-control layer where required

Do You Need These Too?

These products are often useful for completing this type of installation:

·        Alpha Foil Tape — Seal foil-faced board joints and repair small tears for a neat, continuous finish.

·        VCL Vapour Control Layer — Control moisture movement on the warm side of suitable roof, wall and floor constructions.

·        Double Sided Butyl DPM Sealing Tape — Seal suitable membrane laps and perimeter details; check compatibility with your chosen build-up.

You May Also Like

·        Celotex GA4000 PIR Insulation Board — another option for a similar application. Compare thickness, dimensions, thermal performance and system approval before ordering.

·        Celotex XR4000 PIR Insulation Board — another option for a similar application. Compare thickness, dimensions, thermal performance and system approval before ordering.

·        Ecotherm Eco-Versal PIR Insulation Board — another option for a similar application. Compare thickness, dimensions, thermal performance and system approval before ordering.

Looking for an Upgrade?

Recticel Eurothane GP PIR Insulation Board — consider this higher-performance or more integrated route where it suits the construction and required specification.

Key features

• Slim PIR insulation board
• Suitable for reducing thermal bridging
• Ideal where build-up depth is limited
• Suitable for walls, floors and roofs
• 2400mm x 1200mm board size
• 2.88m² coverage per board
• Foil-faced on both sides
• Lightweight, rigid and easy to cut
• Available in 20mm, 25mm, 30mm and 40mm

Technical specifications