Thermal insulation is put through its paces in social-housing retrofit
Kingspan’s Kooltherm K-range of insulation played a key role in boosting the SAP rating of a Victorian villa in Brighton from F to B (33 to 82 points). The Nook, owned by Two Piers Housing Co-operative, won funding of £150 000 from the Technology Strategy Board’s competition ‘Retrofit for the future’, which aims to reduce carbon emissions from the social-housing stock by 80% by 2050. Two Piers provided a further £22 500, covering a shortfall in project costs, contingency and decoration, to help transform the period house, which is spit into several self-contained flats, into a demonstration prototype for its future housing stock.
Project manager Mischa Hewitt form Earthwise Construction explains, ‘We sought technical support from Kingspan because the efficiency of the insulation was integral to the success of the refurbishment.
Thermal conductivity values were vital as we needed to reduce the thickness of the insulation whilst maintaining the required K-values.’
Removing the concrete floor slab was judged to be too costly. However, by taking advantage of the property’s high ceilings and using Thermafloor TF70 high-performance insulation, the floor was raised and insulated to the depth of the first step of the staircase — achieving a U-value of 0.13 W/m2K.
The Nook is a detached property with solid walls. The front aspect could not be insulated externally because it is in a conservation area. This problem was solve by applying Kooltherm K12 framing board and K18 insulated plasterboard to the interior walls.
Exterior walls on the sides and back of the building were insulated externally using Kooltherm K5 external wall board.
A combined U-value for the walls of 0.115 W/m2K was achieved.
Styrozone H 350 R insulation for the attic floor and K7 pitched-roof board achieved a U-value of 0.10 W/m2K for the roof space.
Other energy-efficiency measures included a mechanical ventilation system with heat recovery and a solar water-heating system.
Energy bills for the whole property are expected to be less than £750 a year.