Renovation case study 3

Vanessa lives in Wanaka with her daughter Emily. She enjoys living in such beautiful surroundings but is not so keen on the cold winters. The 1960s house she rents has been very cold and damp and prone to potentially health affecting mould on walls and in cupboards.

A friend suggested she contact a local organisation called ‘Sustainable Wanaka’. This is a charitable trust established to actively promote and manage sustainable development. It does this by integrating ecological, social, cultural and economic goals.  Go to www.sustainablewanaka.co.nz for more information.

While Sustainable Wanaka’s principal role is giving advice on sustainable development, it recently went one step further and facilitated the

Mould on walls

upgrade of Vanessa’s rental home using sustainable materials to improve energy efficiency.  An integrated design concept was the key to the effectiveness of the upgrade.

Vanessa’s rental home was retrofitted by her landlord’s property management agent with:

• R5 insulation installed in the ceilings.
• The living room walls insulated with polystyrene donated by a large new. commercial building in Wanaka which was happy to provide some left-over off-cuts. The walls were also relined.
• Installation of a new, more efficient wood burner (this required building. consent), including a heat transfer system which directs heat into the bedrooms.  The wood burner complies with the new rigourous emissions standards.

  Wall linings

• Polythene laid on the ground under the floors to prevent rising damp. Care was taken to fit and tape the plastic sheeting around the foundations. Foil-faced insulation was installed between the floor joists.
• Installation of a ventilation fan and hood fitted in the kitchen plus moisture in the bathroom was greatly reduced with the installation of a fan heater.
• Infected areas treated for mould.

Vanessa was fortunate that all the work was done while she was away on holiday.  Jessica Winter at Sustainable Wanaka, said “Retrofits are more cost effective and less disruptive when several measures are carried out at the same time and we were able to organise this while Vanessa was away.” 

The cost of the retrofit was $8,500. “Hopefully, when more funds become available, the remaining uninsulated walls in the house will be opened up, insulated and relined. Ideally the windows will be replaced with double glazing” Jessica says. She stresses it is important to ensure all components of a house’s outside walls, floors and roof provide the best thermal resistance possible.

Vanessa is looking forward to a warmer house during winter.

Before the retrofit Sustainable Wanaka took temperature surveys and measured the dampness. Internal temperatures during the winter of 2006 frequently dropped below 10 degrees C and for 3 nights in August the temperature in the living room dropped below 5 degrees C.

Monitoring is continuing to show that there has been an improvement in comfort.  Jessica says “We are not expecting a reduction in energy consumption. We are aiming for higher internal temperatures for the same energy input. We hope that this winter the living room will be consistently above 16 degrees C.