Green Issues

Natural Building Technologies’ (NBT) Diffutherm and Pavatherm Plus wood fibre insulation boards are helping to create a healthy living environment for residents in Dundee, as well as lowering energy usage for the development.

The boards are being used to insulate the external walls of timber frame homes at the mixed social housing development in Dundee, which is owned and managed by Abertay Housing Association.

The project was named ‘Best Affordable Housing Project’ at the Dundee Institute of Architects Design Awards and comprises 14 two-storey semi-detached houses to satisfy general needs, two bungalows for wheelchairs users, and five cottages featuring smart technology and staff support for clients with severe learning difficulties.

Architects Wellwood Leslie specified the Diffutherm and Pavatherm Plus boards for their high thermal mass, which helps to regulate overheating during the summer, their sustainable credentials, being manufactured from over 95% recycled timber, and their inherent breathability, which means that any moisture that gets into the wall structure is expelled harmlessly to the external atmosphere.

Being constructed on a recently cleared brownfield site in a deprived area of the city, the scheme’s external appearance needed to be sympathetic with the surrounding environment.

The homes are therefore finished externally with a combination of NBT render and larch timber cladding. The timber clad sections are insulated with 60mm-thick Pavatherm Plus woodfibre boards externally, with additional insulation installed between the 140mm timber studs, delivering a U-value of 0.18 W/m2K. The rendered areas, where the render is applied directly onto the 100mm thick Diffutherm boards, deliver a U-value of 0.15 W/m2K.

These systems also have minimal thermal bridging, with y-values of 0.03W/m2K and the simple construction ensures high levels of airtightness are maintained throughout the building’s life.

Abertay Housing Association’s development director, Ron McArthur, said: “In providing housing for, often, vulnerable individuals, health promotion and the elimination of fuel poverty are primary factors. The combination of mechanical ventilation with the breathable insulation solutions promotes a healthy internal environment by regulating moisture and air. By installing insulation far beyond current minimum building standards, we have delivered the ability for our residents to drastically reduce their heating demand, thereby minimising their heating bills.”

www.natural-building.co.uk