Solving Leaky Homes at Science in the Park

15 March 2007

The public will get a rare insight from leading scientists into why the leaky home situation happened and how it might be avoided in the future at Science in the Park in Rotorua later this month.

When leaky homes first hit the news in the late 1990s scientists at Crown Research Institute Scion were quick to respond. Research projects into timber and timber treatments best suited to the New Zealand climate began.

At Scion’s Science in the Park festival, a free open day being held on Saturday March 24, members of the public will get to hear directly from scientists involved in research which is aimed at educating builders and building suppliers to improve the quality of New Zealand homes.

Mick Hedley, a senior scientist at Ensis – a joint venture between Scion and CSIRO in Australia, says a number of factors resulted in the leaky homes saga becoming so huge in New Zealand.

“Firstly, untreated timber became legal in 1995 which was a huge mistake. That happened to coincide with European building styles – which included smaller eves, complicated designs and monolithic cladding - becoming fashionable.

“Those designs, combined with untreated timber in the warm and wet New Zealand climate led to leaky homes. At the time scientists were warning the industry of potential problems – we never supported the use of untreated radiata pine framing, but the industry didn't listen,” Dr Hedley says.

Scientists at Scion and Ensis are involved in research looking at the best treatment options for the New Zealand climate and building systems, which timber is best, what other species of timber can be used, and what are the most environmentally-friendly options.

“Our work involves, amongst other experiments, building wall frames and infesting them artificially with decay and then providing warmth and moisture to see how quickly the decay occurs, or, more importantly, to see which treatments best prevent the onset of decay.

“The research is designed to come up with best practice guidelines for the building industry so that we can try and avoid issues like this in the future,” Dr Hedley says.

The latest work by the team of scientists involves putting together a proposal to work with the New Zealand Wood Processors Association to come up with a simplified list of building materials.

“One of the major issues is that there are so many decisions to be made when building a house. We want to help building suppliers and builders to make good decisions about the materials that are used in New Zealand homes,” Dr Hedley says.

Visitors to Scion’s Science in the Park will get to see displays about the leaky homes research taking place at Scion and get to talk to the scientists involved. Other items on the programme include making fermented beverages, identifying insects and how to make a worm farm. The open day provides members of the public with an opportunity to learn what Scion’s 300 scientists do.

Science in the Park is open to all members of the public and includes displays, careers expo, a future farming roadshow, guided tours and seminars for teachers. For more information see or call 07-343-5899.