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PIR boards are one of the most popular types of insulation materials due to its multi-purpose usage and easy application. PIR boards are rigid high-quality boards that are installed to create an insulation envelope around a property to improve the thermal conductivity. PIR boards are lightweight and easy to cut, handle, and install. PIR insulation boards are moisture resistant meaning if they are applied to a clean healthy environment they will prevent damp, mould, and rot from developing by preventing moisture build up. They provide a thermal conductivity of 0.022W/mK and are 1200mm by 2400mm, available in a range of thicknesses from 20mm to 200mm. The boards are extremely durable and long lasting, they will not sag or become feeble over time.

PIR insulation boards are BBA Approved and have a Euroclass E Reaction to Fire classification. They are sustainable and achieve manufacture under Environmental Management System ISO 14001:2015.

What are PIR boards made from?

PIR is a thermoset polymeric material that blends isocyanates and polyols. The manufacturing method creates a chemical reaction that produces a robust, rigid material that makes up the core of the material and does not melt when heated. This is also known as Polyisocyanurate.
The polyisocyanurate board is then bonded with a layer of low emissivity foil to create foil facings on each side to improve thermal quality by storing and increasing heat within the board.
The foil facing can also be used to reflect heat and keep it within a specific area, such as when PIR boards are installed into the ceiling the foil reflects the heat back into the building and begins to heat the property from the ceiling down.

How will I benefit from PIR insulation boards?

  • PIR is cost-effective, you can save up to 30% of your annual energy bills.
  • It will make your property a more comfortable environment by providing better temperature control.
  • It will achieve temperature control by keeping the heat out in the summer and the cold out in the winter as well as maintaining the temperature within the property.
  • It will make your property a more sustainable environment and more energy efficient.
  • It makes your home more energy efficient by keeping the heat in your home which will help prevent climate change and global warming.
  • Specific insulation materials can suit needs such as moisture resistance, soundproofing and fire resistance
  • The correct insulation installed properly can increase the life span of the building and the insulation can last for as long as the building does.

Where can PIR Insulation Boards be applied?

  • Wall insulation – masonry walls, timber frame walls,
  • Roof insulation – between and under rafters
  • Floor insulation – suspended timber floors.
How do you install PIR Insulation Board?

Dot and Dab method:

Step 1. Make markings on the ceiling and floor at the same thickness of the board plus 10mm. The wall should also be marked to show where the centre of the board should be. Horizontal centres can also be marked every 1200mm to show where the edges of each board should be.

Step 2: Cut the boards to the size you need. The boards should be cut 15mm short of the wall height.

Step 3: Make your plasterboard adhesive following the instructions given. A continuous band of adhesive should be applied around the wall, ceiling edge, and openings such as windows and doors.

Step 4: Dab the adhesive onto the wall 50mm to 75mm wide and 250mm long. Three vertical rows should be applied for each board, one in the centre and one on either side making sure it is at least 25mm from the edge. The adhesive should also be applied around the skirting level.

Step 5: Use plasterboard packers to rest the insulation boards on and press the reverse side of the boards against the dabs. Tap it into place using a straight edge and align it with the marks on the ceiling and floor.

Step 6: Use a board lifting and lift the board to the ceiling making sure its tight. Plasterboard packers can be used to hold the boards in place and then the lifter can be removed.

Follow the same process for the rest of the room. Plasterboards can then be added.


  • This method can be applied to plasterboards, insulated plasterboards and PIR boards.
  • The boards take 3 to 6 hours to set.
  • The plasterboard packers should be removed when the adhesive has set.
  • Nails can be applied to the boards to make them extra secure.
  • Unused adhesive will last for 4 months.

Other methods:

PIR insulation boards can be tightly fitted in between rafters and joists with no fixtures or adhesive needed. The boards should be secured with insulation netting materials or overlayed with plasterboard or insulation boards fixed to the rafters or joists.

There are various methods that can be applied when installing PIR insulation boards. The method depends on the location of insulation in the property and the purpose of the insulation. All insulation boards put together should be tightly butter together to avoid thermal bridging. Foil tape can also be applied where boards join and around the board’s edges. PIR Insulation boards should be cut using a hand saw and measured and marked if necessary.

A building professional should be consulted before any insulation boards are fitted into a property to avoid causing damage.

See a range of methods below.

Pitched roof between the rafters –

The insulation boards should be measured and cut to fit vertically between the rafters. Insulation boards should then be fixed horizontally over the top of the rafters and fixed in place using a screw.

Flat roof external applications –

Insulations boards should be measured and cut to size and can be externally applied over the top of the rafters on internally between the rafters. The roof is then finished with weather proofing materials and other fittings such as guttering.

Timber and steel-frames walls –

Once the stud wall has been securely made, the insulation boards should be measured, cut, and placed into the wall’s studs tightly butted together. The plasterboard can then be fixed onto the timber frame and fixed using screws.

Partial fill masonry cavity walls –

This can be applied to new builds or extensions. The insulations boards should be cut to size and fixed in between the outer and inner leaf of the building wall as the wall is being built. Build a layer of brickwork, fix the insulation boards using wall ties and the build up the breeze blocks and continue.

Solid floor insulation –

Insulation is laid above the concrete slab along with a damp-proof membrane. This is followed by a polythene separating layer, and either a concrete screed or tongue and groove chipboard, the underlay and specified floor finish can then be applied.


PIR Insulation boards should be kept in a dry space on a flat surface that is weatherproof. Although rigid, the boards should not be walked on as they may crumble or snap.

PIR Insulation boards are stocked by several well renowned and trusted brands within the building industry. These brands include Celotex, Recticel, Kingspan, Iko Enertherm and more.

The most popular PIR Insulation board is a 100mm thick board.

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