90mm Kingspan Kooltherm K103 Floorboard is supplied here by the pack for floors that need a high thermal resistance from a single layer, with 3 boards covering 8.64m². At 90mm the board reaches 4.70 m²K/W on its own, so buying by the pack lets the order follow the floor area and brings a demanding floor specification in from one batch.

Each board carries a thermal resistance of 4.70 m²K/W, drawn from a fibre-free rigid thermoset phenolic core with a thermal conductivity of 0.019 W/mK. The boards measure 2400mm x 1200mm, have a square edge and are faced on both sides with glass tissue bonded during manufacture, and hold a compressive strength of 120 kPa to BS EN 826:2013, so they cope with the load of a screed or slab laid over them.

The advantage at 90mm is reaching that 4.70 m²K/W from one layer. A single thickness of board means one set of joints to butt and seal across the floor, rather than the two offset layers a doubled-up build of thinner boards would need. For a floor of any size that keeps the lay-up simpler and the run of work faster, with fewer board joints sitting in the insulated layer.

90mm Kingspan Kooltherm K103 is used in beam and dense block, suspended timber and solid concrete ground floors, laid over a damp proof membrane and installed in line with the latest Kingspan guidance and the project specification. In suspended timber floors the boards sit between the joists on battens, saddle clips or nails rather than fixed across the top of them, and the board works with underfloor heating. Ordered by the pack, a higher-resistance floor arrives together and goes down as one consistent layer.

Key Benefits of Kingspan Kooltherm K103:

• 90mm rigid thermoset phenolic floor board with a fibre-free insulation core.
• Thermal conductivity of 0.019 W/mK.
• Thermal resistance (R-value) of 4.70 m²K/W at 90mm.
• Compressive strength of 120 kPa to BS EN 826:2013, for use beneath a floor screed or slab.
• Square edge, faced both sides with glass tissue bonded during manufacture.
• Boards measure 2400mm x 1200mm; 3 boards per pack covering 8.64m².
• Reaches a high resistance in a single layer, so a doubled-up build of thinner boards can often be avoided.
• Suitable for beam and dense block, suspended timber and solid concrete ground floors.
• Compatible with underfloor heating.
• Reaction to fire classification of Euroclass C-s2,d0 to BS EN 13501-1:2018.

Good to know:

• The 4.70 m²K/W figure is the board's thermal resistance, not the finished floor U-value; confirm the U-value against the full build-up before ordering the packs.
• Set the boards over a damp proof membrane of at least 1200 gauge, with no direct contact between the insulation and the subsoil.
• In suspended timber floors the boards sit between the joists on battens, saddle clips or nails, not fixed across the top of them.
• K103 resists the passage of water vapour but is not a vapour control layer; under a screed, lay a separate lapped and taped polythene sheet as the VCL.
• If a build calls for more than 90mm, boards can be doubled up in a break-bonded pattern with the joints staggered between the layers.

For a floor that needs to reach a demanding U-value in one layer, the three-board 90mm packs let you order by area and cover the job from a single delivery.