Kingspan’s premium performance Kooltherm K5 External Wall Board has been installed as part of a new refurbishment scheme in Hampshire; transforming thirteen former council houses, already well past their envisaged lifespan, into highly energy efficient housing stock.
The properties on Borough Grove in Petersfield were built in the 1950’s using an uninsulated concrete REEMA construction. The refurbishment project was managed by Radian (previously Drum Housing Association) and followed their successful retrofit of twenty similar houses on Highfield Road in Petersfield, again using Kingspan Kooltherm K5 External Wall Board. Both schemes form part of the ‘Retrofit South East’ project, part-funded by the European Regional Development Fund, which aims to develop a model for low carbon retrofit.
A preliminary survey of the Borough Grove houses found they achieved an Energy Efficiency Rating of “E”. A key reason for this poor Rating was the lack of any wall insulation, resulting in an external wall U-value of 2.34W/m2.K and subsequent high levels of heat loss. To improve this, 100mm of Kooltherm K5 External Wall Board was installed as part of a Wetherby Insulated Render System.
Kooltherm K5 External Wall Board is designed to be installed behind traditional or lightweight polymer modified renders and dry cladding systems, such as the ‘K’ Silicone Render used at Borough Grove. It can achieve outstanding thermal conductivities as low as 0.020 W/m.K, with minimal thicknesses, reducing the size of the final wall solution. To minimise thermal bridging on the project the Kooltherm K5 was also returned around corners of windows and doors to a thickness of 25 mm. The installation greatly improved the thermal performance of the walls, achieving a final U-value of 0.3W/m2.K, whilst the ‘K’ Silicone Render also provided a much needed face lift to the properties.
Jes Dickin, Stock Options Surveyor from Radian commented: “Our initial analysis showed that the uninsulated walls were responsible for over half of the heat loss from the properties so getting the external solution right was vital. The system combining Kooltherm K5 with Wetherby ‘K’ Silicone Render was simple and efficient to install, while also reducing the wall heat loss by a factor of nearly 10.”
The Borough Grove scheme also includes a range of other energy-saving and generating features such as roof-mounted PV and solar water heating panels and new high performance windows. The combination of these features with the external wall solution brought a large improvement in the overall performance of the houses with the seven east facing properties achieving a final Energy Efficiency Rating of ‘B’, whilst the six south-east facing homes were rated ‘A’.