Ysgol Y Garnedd
On course for BREEAM ‘Excellent’ with a specification including underfloor insulation boards
Case Study6 min read
The spa town of Cheltenham is known across the world for its annual Festival, which culminates in the Gold Cup. In recent years, however, available commercial floor space within the attractive town had dwindled as a result of office to residential conversions. With Honeybourne Place, Formal Investments aimed to reverse this trend and set the standard for office developments.
LOCATIONCheltenham, UK
ProductsKooltherm K103 Floorboard
Barnwood Construction acted as main contractor for the 6-storey building, which has been constructed over a former car park. In total, the development provides almost 6,000 m2 of Grade-A office space.
In developing the design, the architects looked to raise the bar in terms of energy performance, setting rigorous thermal performance targets for the building envelope including a maximum U-value of 0.14 W/m2K for the concrete ground floor. To deliver this, they specified over 1,000 metres of our Kooltherm K103 underfloor insulation boards.
Kooltherm K103 is one of the thinnest commonly used insulation for floors, allowing U-values to be reached with minimal thickness. As a result, the project team were able to meet the U-value target with an insulation thickness of just 75 mm. This helped to limit the scale of groundworks and soil removal, avoiding potential additional costs associated with this work and keeping the project on schedule.
Nationwide Concreting Ltd fitted the insulation above a damp-proof membrane and hardcode followed by a separation layer. The lightweight boards were loose-laid in a break-bond pattern, with all joints lightly butted. Kooltherm K103 can be simply cut to size with a fine-toothed saw or by scoring the boards with a retractable knife and snapping the boards over a straight edge. Nationwide Concreting then installed a protection layer followed by the rebar reinforced slab, ready to receive the screed and finished flooring surface.
Page updated 6/1/2026
Discover More
