Steel frames may be the standard for commercial buildings in New Zealand, but they are much less common in house construction.

Timber has always been the traditional framing material for Kiwi homes - the material grows all around us and all builders know how to handle it.

But the use of steel framing is on the increase, with at least one house building company moving away from timber frames. As well, the National Association of Steel-Framed Housing (Nash) is putting together a series of industry standards and running roadshows to share information about steel framing.

Steel house-framing panels are pre-assembled in a factory complete with plumbing and wiring holes. The frames are trucked in and erected onsite, held together with self-drilling screws.

Like timber, the material is produced in New Zealand. At Glenbrook, south of Auckland, New Zealand Steel, using ironsand off Waikato beaches, turns out frames for the local market.

Nash general manager Carl Davies says the association is trying to raise awareness by telling builders, local councils and the public about steel framing.

Davies says concerns over chemicals leaking from timber in leaky homes has helped drive interest in alternatives to wood.

"We've still got a small market share but it's growing and we are up to about five per cent."

He says as steel represents a smaller percentage of the finished cost of a frame than with timber, frame prices are less sensitive to any material price increases.

Golden Homes owner Pavlos van Aalst says his company has decided it will now be using steel frames exclusively. The reason is the leaky homes problem.

Steel framing needs no chemicals and is about the same price as using treated timber, he says.

While Kiwis are not used to steel frame homes they are common in other parts of the world. "It's definitely something New Zealanders find difficult. It's quite hard for them to understand."

Van Aalst believes no other large companies are using steel framing in residential building.

Like any other building material, steel has its pros and cons. Steel is light and strong and can be put up quickly in any weather.

Because it doesn't absorb moisture it won't rot or grow the toxic moulds which have caused health worries in leaky homes.

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Because framing with steel uses different skills to working with timber, homeowners wanting the material will need a builder with experience in it.

Nash figures show more than 120,000 steel-framed homes are built annually in the United States, 150,000 in Japan and 10,000 in Australia.

In New Zealand, steel house frames were first used in the late 1960s. Since then alloy coating has replaced galvanising, while new fastening systems and computer technology have made the business easier and cheaper.

At the estimated five per cent of market share, steel frames would have been in about 750 of the 15,000 homes built in the past year in New Zealand, with the shift by Golden Homes set to boost that number.

By LIZ MCDONALD - The Press