150mm Kingspan Kooltherm K103 Floorboard is supplied here by the pack for floors specified at the deepest, highest-resistance board in the range, with 2 boards covering 5.76m². At 150mm each board reaches 7.85 m²K/W, so ordering by the pack lets a low-energy floor specification be covered and delivered as one batch rather than gathered board by board.

Each board carries a thermal resistance of 7.85 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, even at this full 150mm depth.

Over a whole floor the gain at 150mm is reaching that 7.85 m²K/W in one layer. A single thickness of board gives one set of joints to butt and seal across the area, rather than the two offset layers a doubled-up build of thinner boards would need, and sheet after sheet from the same packs the insulated layer stays consistent from one side of the floor to the other. Because the boards are larger units of cover, a floor is closed in fewer pieces, with fewer joints sitting in the layer.

150mm 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 set to suit the 150mm depth, rather than fixed across the top of them, and the board works with underfloor heating. Ordered by the pack, a full low-energy floor arrives together and goes down as one consistent layer.

Key Benefits of Kingspan Kooltherm K103:

• 150mm rigid thermoset phenolic floor board with a fibre-free insulation core, the deepest in the K103 floorboard range.
• Thermal conductivity of 0.019 W/mK.
• Thermal resistance (R-value) of 7.85 m²K/W at 150mm, the highest in the range.
• 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; 2 boards per pack covering 5.76m².
• 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 7.85 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.
• At 150mm the support height matters: in suspended timber floors set the batten or saddle-clip height so the boards sit between the joists, and check threshold and finished-floor clearances before ordering.
• 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.
• 150mm is the deepest single board in the range; where a build needs more depth, two boards can be laid in a break-bonded pattern with the joints staggered between layers.

Only need a couple of boards? The same 150mm board is sold as single sheets here.

For a full floor going in at 150mm, the two-board packs let you order straight off the floor area and bring the range's deepest board in from one delivery.