Kingspan TR26 is part of the Thermaroof range designed for the insulation of flat roofs. Specifically flat roofs, waterproofed with fixed single-ply waterproofing. This product is compatible with single-ply waterproofing systems and most green roof systems. The Kingspan TR26 PIR board is suitable for new builds, extensions, and refurbishments. The installation technique creates a flat roof insulation solution for fast-track building programs.

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Kingspan continues to manufacture insulation materials whilst upholding its long-term commitment to sustainability.

This board is a high-quality, rigid thermoset insulation board. The core is made up of fibre-free polyisocyanurate and each side of the board is bonded to low emissivity composite foil facings. The board is CFC and HCFC free and offers a thermal conductivity of 0.022W/mK. The TR26 is 1200mm by 2400mm and is available in a range of thicknesses from 25mm to 150mm.

Key features:

  • Ideal for new build and refurbishment.
  • Composed of non–deleterious material.
  • Zero Ozone Depletion Potential and low Global Warming Potential.
  • Resistant to solvents, fungi & rodents.
  • Installation technique is ideal for fast-track building programmes
  • Compressive strength at 10% compression: 150 kPa
  • Resistant to the passage of water vapour.
  • Available with FM Approval to FM 4470 – please see the product brochure for the conditions of approval.
  • Installation technique is suitable for fast-track building programmes.
  • Multiple installation methods available.

The TR26 is lightweight making delivering, handling, cutting, and installing easy. If you should need to cut the TR26 board this product can be cut using a hand saw. The product should be accurately measured to size and marked, if necessary, then placed on a slightly higher flat surface with room for the saw to go through the board. A ruler or plank of wood can be used for a guide and to hold the board in place when cutting.

Kingspan TR26 is extremely durable and long lasting. When the product is installed correctly under the proper building regulations the product should last for as long as the building does. The TR26 is resistant to the passage of water vapour and moisture resistant, presenting the ideal product to be installed in an area that invites challenging weather conditions. This board will prevent mould, damp, and condensation from developing and will not rot even if these conditions should occur. It is also resistant to solvent, fungi, and rodents.

By insulating your roof you’re preventing heat from escaping your property through the roof. By doing so, you will be contributing to a more sustainable environment by helping to tackle climate change and prevent global warming. You will also save money on your energy bills and provide a more temperature-controlled and comfortable residential or commercial property. Your property will be cooler in the summer and hotter in the winter.

Kingspan TR26 can be installed in a range of methods such as:

  • Dense Concrete Deck with Suspended Ceiling
  • Timber Deck with Plasterboard Ceiling
  • Metal Deck with No Ceiling
  • Extensive Green Roof Covering – Metal Deck with No Ceiling
  • Semi-intensive Green Roof Covering – Dense Concrete Deck with Suspended Ceiling


  • BS EN ISO 9001: 2015
  • BS EN ISO 14001: 2015
  • BS OHSAS 18001: 2007
  • ISO 50001: 2011
  • ISO 45001: 2018 (Occupational Health & Safety Management Systems. Requirements with guidance for use)


This is a guide and building professionals should always be consulted.

  • Insulation board should be tightly butted together to achieve the best possible thermal performance and to avoid thermal bridging and heat escaping through gaps within the insulation.
  • Board should be stored on a flat surface in a weatherproof environment. Avoid standing on the boards.
  • A building professional should always be consulted before and installation takes place to ensure you have the correct products and method of insulation required for your specific property.
  • Protected clothing, goggles, face masks, and gloves are recommended when cutting insulation as the particles produced can irritate the skin and eyes.
  • Guideline given with each product should be read and followed.


  • A separate vapour control layer should have of a minimum of 1000 gauge (250 micron) polythene sheet. All joints of the sheet should be lapped and sealed with double sided self-adhesive tape.
  • Green Roofs Kingspan TR26 is appropriate to use under most green roof systems. Green roof systems are a specialist design area.
  • When constructing a loose-laid insulated green roof, assembly understanding needs to be given to the following:

When implementing Green roof systems it is essential to have a minimum dry weight of 80 kg/m2 to balance the insulation boards beneath them. However, the total necessary dry weight will depend on wind uplift, which in turn will vary with the location of the building, local topography, and size (height and width) of the roof affected.

The necessity for any additional dry weight should be assessed in accordance with BS EN 1991-1-4: 2005 + A1: 2010 (National Annex to Eurocode 1 Actions on structures. General Actions. Wind Actions).

When installing a loose-laid insulated green roof construction, any insulation must be instantly over-laid with the green roof system, which must meet all of the requirements outlined above.

If the above requirements cannot be guaranteed, the insulation must be mechanically attached (see Sitework).


  • The water Vapour Control Thermaroof TR26 should be installed over a separate vapour control layer, in new build roofs. This is unless the board is being combined with a sealed metal deck.
  • A condensation risk analysis should be carried out for every project, regardless of the deck type.
  • When refurbishment a property involving adding additional insulation to existing insulated flat roofs, or roofs built of insulated steel faced composite panels, U-value calculations and condensation risk analyses should be carried out for every project. This will ensure that the proper thickness of insulation is installed so the required thermal performance is achieved, whilst avoiding interstitial condensation.
  • In refurbishment projects, where Kingspan Thermaroof TR26 is being installed over a remaining bituminous waterproofing membrane, the membrane can be treated as a vapour control layer, if it is in good watertight condition. Where this is not the case, a separate vapour control layer should be applied. A minimum separate vapour control layer should contain a 1000 gauge (250 micron) polythene sheet, with all joints lapped and then sealed with double sided self-adhesive tape.