100mm Kingspan Kooltherm K103 Floorboard is supplied here by the pack for floors specified at the range's highest single-board resistance, with 3 boards covering 8.64m². At 100mm each board reaches 5.25 m²K/W, so ordering by the pack lets a demanding floor specification be covered and delivered as one batch rather than gathered board by board.

Each board carries a thermal resistance of 5.25 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. Across a pack-bought floor that means every sheet brings the same resistance and the same load rating to the build.

Over a large floor that consistency is what counts. A 100mm board gives the full 5.25 m²K/W in a single layer, so the whole area is insulated in one pass with one set of joints to butt and seal, rather than the two offset layers a doubled-up build of thinner boards would call for. Sheet after sheet from the same packs, the insulated layer behaves the same from one side of the floor to the other.

100mm 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 full high-resistance floor arrives together and goes down as one consistent layer.

Key Benefits of Kingspan Kooltherm K103:

• 100mm rigid thermoset phenolic floor board with a fibre-free insulation core.
• Thermal conductivity of 0.019 W/mK.
• Thermal resistance (R-value) of 5.25 m²K/W at 100mm, the highest from a single K103 board.
• 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.
• Supplied by the pack for whole-floor coverage and ordering by area.
• 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 5.25 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.
• In suspended timber floors the boards sit between the joists on battens, saddle clips or nails, not fixed across the top of them.
• Set the boards over a damp proof membrane of at least 1200 gauge, keeping the insulation off the subsoil.
• K103 resists the passage of water vapour but is not a vapour control layer; where it goes under a screed, run a separate lapped and taped polythene sheet as the VCL.
• If a build needs more than 100mm, boards can be doubled up in a break-bonded pattern with the joints staggered between layers.

Only need a few boards? The same 100mm board is sold as single sheets here.

For a full floor going in at 100mm, the three-board packs let you order straight off the floor area and cover the job from one delivery.