House fit for a picnic

Walls like a chilly bin

BY PIERS FULLER

The builder calls this house the biggest chilly bin in the Wairarapa, and for good reason.

It uses revolutionary polystyrene technology for its outer walls and, like a chilly bin, it has amazing insulation properties.

Dave Denham, of Kwando Construction, and Brendan McBride, of Brendan the Builder from Upper Hutt, are over in Wairarapa putting up the house at Matahiwi for Peter and Ruth Ruddock, of Masterton.

The walls are made of solid polystyrene panels that are precision cut to interlock with each other.

This method is called insulated concrete formworks, rather than timber frame.

It is understood this Matahiwi house is the first in Wairarapa to be constructed in this way.

The internal walls of the building are timber frame as is the roof, which is supported by concrete columns within the polystyrene walls.

It has an incredible insulation rating value of R5.7, which puts it way ahead of conventional insulation.

Peter and Ruth are from Britain and they were looking to build something nice and warm with a focus on energy efficiency.

"When we were in England we had a house that was very well insulated compared to what you get in a standard house in New Zealand," he says.

Peter researched various methods on the internet and discovered this polystyrene technology.

On the ecobob.co.nz website, which specialises in eco-friendly building construction techniques, he found the Christchurch company, Cornerstone, that manufactures the polystyrene system.

The cost, once you have taken into account the various factors needed in conventional walls including insulation, is not much more, according to Peter.

The Ruddocks have also decided to install other energy-saving technologies, such as a solar panels and heat pumps.

"There are a few innovative things that you wouldn't find in standard spec housing," he says.

They're also running underfloor heating from a hot-water heat pump and an air ventilation system to remove moisture from inside the house.

"What we're hoping for is that our heating costs will be very, very low," he says.

It is possible to plaster straight onto the polystyrene panels but the Ruddocks have opted for a more classic look.

"We're going to clad it in weatherboard, so that once it's built and completed, you wouldn't know that it was a polystyrene house," he says.

Another advantage of using these large panels is that the walls go up in a very short time indeed, saving in labour costs.

- Wairarapa News