NZ Wood responds to Sunday Star Times' article

Howick Engineering’s international success at selling machines to produce steel framing for houses in last Sunday’s Star-Times was commendable. The entrepreneurial successes of small, innovative New Zealand companies on a global stage are something we can all take heart from.

What was unfortunate was the claim made in the story that steel-framed houses are better than those made from wood, and that ‘lil ol’ New Zealand’ just wasn’t getting this message.

Maybe New Zealander’s aren’t getting this message because it’s simply untrue. And wood framing is set to make even more sense in a world concerned with global warming.

That’s because, strength for strength, sustainably grown timber has an overwhelming advantage with which steel can never compete. Wood is one of the few construction materials that can not only save you money, it can save the planet.

The wood in a typical wooden-framed house has actually removed and stored as much carbon from the atmosphere as the steel in a steel-framed house has belched into it. Twenty-seven tonnes worth, in fact.

The timber industry grouping, NZ Wood, has just had engineers at Canterbury University do the sums based on a typical modern New Zealand home and the differences in terms of environmental impact between wood and steel are stark and compelling.

An all-wood home has a carbon footprint of minus 27 tonnes net of CO₂, thanks to all the CO₂ the trees have soaked up from the air when they were growing. Conversely, a steel-framed, concrete-floored, aluminium windowed house is responsible for contributing another 27 tonnes of CO₂ towards global warning.¹

This gives an all-wood house a net 54 tonne environmental advantage over the steel and concrete alternative. And when emissions trading schemes kick in around the world, ultimately the consumer will be the one paying the price. With steel already rocketing in price in the last few years, the environmentally friendly choice will also continue to be the most economic.

Even in the United States, the ‘nation built on steel’, 90 percent of people still live in a traditional wooden-frame home. That’s because wood has many advantages and few disadvantages compared with other materials.

Wood provides superior thermal insulation. Steel conducts heat out of the home, requiring extra insulation against heat loss.

Contrary to popular belief, a wooden frame can often perform better in a fire than a steel one. Light gauge steel can melt, distort and fail, facilitating progress of the heat and flames up through the wall cavity. Wooden members tend only to char on the surface, leaving the structure intact.

Wood-frames are also more versatile and, unlike steel-frames, can be easily modified during or after construction.

And the claim that steel frames can alleviate New Zealand’s leaky building syndrome are spurious. The prime culprit for leaky buildings is the cladding methods used. It was the recent trend away from weatherboard to monolithic claddings that sparked the problem.

A well designed and constructed wooden-framed building will stay just as weathertight as a steel-framed building – evidenced by all the housing stock that has lasted well beyond 50 years.

[Note 1: The CO₂ calculations are based on the material’s production only – “cradle to gate”. They do not include emissions associated with transport to site, construction or ongoing utilisation of the building.]

Geoff Henley
Programme manager for NZ Wood

ENDS

For more information please contact either:

Geoff Henley
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or
Brian Langham

021 784 626