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PIR Insulation Board

PIR insulation, also called Polyisocyanurate or PIR board, is a high-performance, rigid foam insulation with excellent thermal conductivity. It is moisture resistant and offers strong fire resistance. Suitable for lofts, floors, and walls, PIR board is space-saving thanks to its thin design. Our range of PIR insulation includes various sizes from Unilin.

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    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 50mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
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    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 100mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
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    Unilin XT Thermal Liner DD Insulation PIR Board 2400 x 1200 x 32.5mm

    Unilin / Xtratherm XT Thermal Liner is specifically designed to create a thermal break in the building envelope and provide a maximum level of insulation with minimal acoustic impact. It is perfectly suited to modern constructions projects where high...
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    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 75mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
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    Unilin XT Thermal Liner DD Insulation PIR Board 2400 x 1200 x 37.5mm

    Unilin / Xtratherm XT Thermal Liner is specifically designed to create a thermal break in the building envelope and provide a maximum level of insulation with minimal acoustic impact. It is perfectly suited to modern constructions projects where high...
  • XTCWP.png

    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 60mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
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    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 90mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
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    Unilin Thin-R Cavity Wall Corner T&G Insulation PIR Board 1200 x 450 x 100mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) features engineered tongue and grooved joints and pre-formed corners, ensuring insulation continuity and minimisation of thermal bridging. Each element automatically builds to a system thanks to it's...
  • XTCW%20%28T_G%29.png

    Unilin Thin-R Cavity Wall Corner T&G Insulation PIR Board 1200 x 450 x 50mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) features engineered tongue and grooved joints and pre-formed corners, ensuring insulation continuity and minimisation of thermal bridging. Each element automatically builds to a system thanks to it's...
  • XTCW%20%28T_G%29.png

    Unilin Thin-R Cavity Wall Corner T&G Insulation PIR Board 1200 x 450 x 60mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) features engineered tongue and grooved joints and pre-formed corners, ensuring insulation continuity and minimisation of thermal bridging. Each element automatically builds to a system thanks to it's...
  • XTCW%20%28T_G%29.png

    Unilin Thin-R Cavity Wall Corner T&G Insulation PIR Board 1200 x 450 x 75mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) features engineered tongue and grooved joints and pre-formed corners, ensuring insulation continuity and minimisation of thermal bridging. Each element automatically builds to a system thanks to it's...
  • XTCW%20%28T_G%29.png

    Unilin Thin-R Cavity Wall Corner T&G Insulation PIR Board 1200 x 450 x 80mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) features engineered tongue and grooved joints and pre-formed corners, ensuring insulation continuity and minimisation of thermal bridging. Each element automatically builds to a system thanks to it's...
  • XTCW%20%28T_G%29.png

    Unilin Thin-R Cavity Wall Corner T&G Insulation PIR Board 1200 x 450 x 90mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) features engineered tongue and grooved joints and pre-formed corners, ensuring insulation continuity and minimisation of thermal bridging. Each element automatically builds to a system thanks to it's...
  • XTCWP.png

    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 70mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
  • XTCWP.png

    Unilin Thin-R Cavity Wall Insulation PIR Board 1200 x 450 x 80mm

    Thin-R CW is pre-formed to a system, building to the highest thermal standards whilst maintaining a residual cavity, offering protection from wind driven rain. XT/CW (T&G) for use in traditional masonry walls, builds to the highest thermal standards...
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    Unilin Thin-R Cavity Wall T&G Insulation PIR Board 1200 x 450 x 100mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) insulation builds to a system, thanks to its engineered tongue and grooved joints and pre-formed corners. This ensures insulation continuity and minimisation of thermal bridging. XT/CW (T&G) is made for...
  • XTCF_IMG_001.pdf.png

    Unilin Thin-R Cavity Wall T&G Insulation PIR Board 1200 x 450 x 50mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) insulation builds to a system, thanks to its engineered tongue and grooved joints and pre-formed corners. This ensures insulation continuity and minimisation of thermal bridging. XT/CW (T&G) is made for...
  • XTCF_IMG_001.pdf.png

    Unilin Thin-R Cavity Wall T&G Insulation PIR Board 1200 x 450 x 60mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) insulation builds to a system, thanks to its engineered tongue and grooved joints and pre-formed corners. This ensures insulation continuity and minimisation of thermal bridging. XT/CW (T&G) is made for...
  • XTCF_IMG_001.pdf.png

    Unilin Thin-R Cavity Wall T&G Insulation PIR Board 1200 x 450 x 75mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) insulation builds to a system, thanks to its engineered tongue and grooved joints and pre-formed corners. This ensures insulation continuity and minimisation of thermal bridging. XT/CW (T&G) is made for...
  • XTCF_IMG_001.pdf.png

    Unilin Thin-R Cavity Wall T&G Insulation PIR Board 1200 x 450 x 80mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) insulation builds to a system, thanks to its engineered tongue and grooved joints and pre-formed corners. This ensures insulation continuity and minimisation of thermal bridging. XT/CW (T&G) is made for...
  • XTCF_IMG_001.pdf.png

    Unilin Thin-R Cavity Wall T&G Insulation PIR Board 1200 x 450 x 90mm

    Unilin / Xtratherm Thin-R Cavity Wall XT/CW (T&G) insulation builds to a system, thanks to its engineered tongue and grooved joints and pre-formed corners. This ensures insulation continuity and minimisation of thermal bridging. XT/CW (T&G) is made for...
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    Unilin Thin-R Flat Roof ALU Single Ply Insulation PIR Board 2400 x 1200 x 100mm

    Unilin / Xtratherm FR/ALU is a high performance Polyisocyanurate flat roof insulation with vapour-tight aluminium foil facings suitable for use with single ply membranes. Designed to fit and seal the full range of single ply roofing systems. The unique...
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    Unilin Thin-R Flat Roof ALU Single Ply Insulation PIR Board 2400 x 1200 x 110mm

    Unilin / Xtratherm FR/ALU is a high performance Polyisocyanurate flat roof insulation with vapour-tight aluminium foil facings suitable for use with single ply membranes. Designed to fit and seal the full range of single ply roofing systems. The unique...
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    Unilin Thin-R Flat Roof ALU Single Ply Insulation PIR Board 2400 x 1200 x 120mm

    Unilin / Xtratherm FR/ALU is a high performance Polyisocyanurate flat roof insulation with vapour-tight aluminium foil facings suitable for use with single ply membranes. Designed to fit and seal the full range of single ply roofing systems. The unique...

PIR Insulation Board

What are PIR boards?

PIR stands for Polyisocyanurate — a rigid type of thermal insulation made from plastic foam.

First introduced in the 1960s as an upgrade to PUR (Polyurethane) boards, PIR offers better insulation performance and versatility.

Where can PIR Insulation be used?

  • Walls – Products like Ecoliner are ideal for insulating and drylining internal walls. Eco-Versal suits timber frame walls, with both sides faced in aluminium foil for improved efficiency. As the name suggests, Eco Cavity is designed for cavity or masonry walls and fits standard brick and block dimensions.
  • Flooring – Works with most flooring types, including timber, solid concrete, and suspended floors. Insulating floors helps prevent heat loss and keeps interiors warmer.
  • Lofts – Loft spaces are one of the most common areas for heat loss. Using PIR or PUR insulation can improve energy efficiency and reduce heating costs.
  • Eco-Versal versatility – A popular PIR option that works across pitched roofs, walls, loft ceilings, and floors for consistent thermal performance throughout the home.

Frequently Asked Questions

What is pir insulation?
Polyisocyanurate (PIR) is one of the most efficient insulation materials used in construction. Pir insulation boards are typically available in the following sizes: 25mm, 75mm, 100mm, 120mm and 150mm.
What does pir stand for in pir insulation?
Polyisocyanurate, also referred to as PIR, is a thermoset plastic typically produced as a foam and used as rigid thermal insulation.
Is pir insulation flammable?
Whilst we urge you to refer to the manufacturer’s fire testing certifications, commercially available PIR insulation is not typically flammable.
Is pir insulation waterproof?
While PIR insulation boards are generally resistant to moisture, they are not fully waterproof.
What is the difference between pir and phenolic insulation?
As with the PIR/PUR boards above, phenolic insulation boards also have a closed cell structure. Phenolic board has a slightly higher r-value (higher is better, unlike u-values) and a slightly thinner profile than PIR/PUR boards due to the manufacturing process.

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