Wood buildings getting taller and NZ among the pioneers

OPINION innovative timber construction, and fire and earthquake risk, and who has spent time at the Wood Innovation and Design Centre in Canada.

Canadians got off to an early start in 2014, when they constructed an eight-storey building out of douglas fir. It was among the tallest wooden buildings in the world at the time, and it has served as a model for builders everywhere.

In 2015, Norwegians built a 14-storey wooden tower comprising 62 flats, with offices and shops. In 2016, a 53-metre wooden dormitory was built at the University of British Columbia by four workers in only 70 days.

Another 30-storey building is planned for Vancouver and Austrians are currently building an 84-metre wooden building. Cambridge University architects and engineers have a 300m high wooden building on the drawing board, and which they hope to put up in London.

Plenty of two- and three-storey wooden buildings are currently being used for social housing in London.

These builders use no ordinary wood, as it is too soft and weak. Instead they cut wood into thin slices and cross-laminate them. That is to say, the sawn slices are laid on top of each other at right angles and cemented together under high pressure with resins and glues. Huge 3m by 6m blocks can be manufactured.

Enthusiasts claim that the laminated product is as strong as steel. The wood is lighter in weight so can be erected on sites too difficult for heavier concrete and steel structures. Wood is relatively inexpensive, so its buildings are 9 per cent to 14 per cent cheaper than similar conventional concrete and steel buildings.

Paradoxically, laminated wood is more fire-resistant than steel. This is because the big blocks char on the outside and this protects the structural integrity of the wood inside and, unlike steel, wood does not bend when it gets hot.

Wood is environmentally friendly because it is a lowercarbon product than concrete and steel. Used on a large scale, it is potentially useful in staving off global warming.

New tall residential and commercial buildings are creating a changing mindset among architects and builders.

I looked up ‘‘tallest wooden buildings’’ on Google and got 3.3 million hits.

Unmodified radiata pine is too weak to construct tall buildings but when cross-laminated is as versatile as any wood in the world. Local researchers have developed new and better ways of laminating wood here.

At Rotorua they soak the wood with vinegar. It’s a thriving industry here, with more laminated timber manufactured in New Zealand than in the US and UK combined. Increasingly larger quantities of our engineered wood are being exported these days, including beams for two 40-metre bridges in the Netherlands.

With plenty of successful research and innovation, New Zealand is in a good position to establish a centre for developing the technology.