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Forestry Minister Jim Anderton wants designers of government buildings such as schools, health clinics and offices to offer a version to be built in wood.
"The Government has got to give leadership here," Mr Anderton said.
The minister said he wanted to get more wood-based products into non-traditional uses, especially in commercial buildings.
"I'm preparing policy papers on wood procurement for the Government, leading towards a recommendation that whenever a government building is built, we ask for a wood-based alternative to steel or concrete construction," he said.
The minister yesterday released a cost and environmental impact analysis on the use of timber in some government buildings.
The reason wood was not being used more in commercial buildings had a lot to do with the perception of wood by specifiers, builders and building owners, the report said.
Speaking in the largest wooden building in the Southern Hemisphere - the old government buildings now used by the Victoria University law faculty - Mr Anderton said that by asking for alternative wood designs, "we will get some impetus into providing alternatives to the normal steel-reinforced concrete or steel buildings".
"Once ... some wood buildings are chosen, then I think we'll start to see a lot more interest".
Buildings constructed of wood from plantation forestry were cheaper and had fewer greenhouse gas emissions than steel and concrete alternatives.
"It's not only cheaper in terms of the construction cost by 5-7 per cent, but it's cheaper over the lifetime of the building by 5-10 per cent," Mr Anderton said. "Because of the issues around climate change, it's much more preferable to build in wood than in concrete and steel, which are high energy users in their production."
But the Government was not yet asking for construction tenders to be assessed on their "embodied" greenhouse gas emissions as well as their direct economic cost.
Asked if there was scope to start taking into account the carbon cost of a building over its lifetime, Mr Anderton said: "We have to start considering the environmental consequences. The energy costs and the environmental costs are issues we have to start thinking through."
The analysis by the Building Research Association of NZ showed wood for government buildings required relatively little energy to process, compared with steel, concrete and aluminium.
It showed a timber gymnasium was 4 per cent less expensive than a similar-sized steel design, and 11 per cent less expensive than a concrete version. For an outpatient clinic, timber was 7 per cent less expensive than steel, and 9 per cent less costly than concrete.
Over a 50-year "whole life" of the buildings, the outpatient building was 4-5 per cent more expensive in steel and concrete.
The report also noted steel and concrete had some environmental advantages in terms of recycling construction materials, timber might have greater fire protection costs, and concrete and steel were more robust than timber.
The report called for a "green guide" to building specifications in NZ, similar to the British approach, which showed the economic and environmental costs of different materials.
- NZPA
