Sun, Aug 25, 2019 - Page 7 News List

Wooden skyscrapers sprout over concrete concerns

Worries about climate change have prompted experts to push local authorities toward promulgating regulations for more wooden buildings

By Rina Chandran  /  Thomson Reuters Foundation, HONG KONG

Illustration: Constance Chou

For more than a century, countries have raced to build the world’s tallest buildings with concrete and steel. Now, a quiet contest in constructing tall wooden buildings, from Amsterdam to Tokyo, underlines growing environmental concerns over concrete.

With rapid advances in engineered wood and authorities relaxing building codes, wooden structures are sprouting across Europe, Canada, the US and in the Asia-Pacific region.

At 73m, Amsterdam’s Haut building is said to be the world’s tallest wooden residential tower.

Vancouver plans a 40-story building that it says will be the world’s tallest, a title also claimed by Sumitomo Forestry’s 350m skyscraper in Tokyo.

“The interest is definitely being driven by environmental concerns — the amount of damage we’re doing with concrete is unbelievable,” said John Hardy, a sustainability expert in Bali, Indonesia.

“Bamboo and wood are carbon sequestering materials. So the other advantage of building with them is that you will look better to your children and grandchildren,” he said.

Construction of office towers, bridges, airports and highways is booming in developing nations across the world.

The manufacture of steel, concrete and brick accounts for about 16 percent of global fossil-fuel consumption and up to 30 percent when transport and assembly of the materials is considered, according to the Yale School of Forestry and Environmental Studies.

Concrete is also blamed for rampant sand mining, which has damaged the environment and hurt livelihoods in Southeast Asia.

In addition, an abundance of concrete has worsened urban flooding and made cities hotter, environmentalists say.

In contrast, wood requires fewer fossil fuels to transport and assemble, and also effectively stores large amounts of carbon — trapped as the trees grew — for years, helping curb emissions, said Andy Buchanan, professor of timber design at the University of Canterbury in New Zealand.

Each cubic meter of timber used in construction stores a carbon equivalent of over 900kg of carbon dioxide emissions, meaning a reduction of 135kg to 360kg of emissions per square meter of floor area, Buchanan said.

Innovations such as glue-laminated timber, laminated veneer lumber and cross-laminated timber — strips of wood glued together to make beams — are creating more uses for structural timber in residential and commercial projects, he said.

Structural timber is much lighter than concrete, cuts risks in earthquakes and can “create far more attractive interiors,” he said. “As tall, timber buildings become more popular, the perceived disadvantages — fire safety, durability and the supply chain — are being overcome with good design, excellent case study buildings and technology for engineered-wood products.”

Examples are easy to find, from London’s nine-story residential Stadthaus to Melbourne’s 10-story Forte apartment building.

A 54m wooden building in Vancouver that was thought to be the world’s tallest was quickly overtaken by an 85m tower in Norway.

Amsterdam’s 73m Haut will begin handing over its 55 apartments from 2021. Vancouver’s planned 40-story building will include 200 apartments, while the 70-story Tokyo tower is slated to be completed by 2041.

“New technology, combined with accurate computer fabrication, now enables a wooden building to be assembled incredibly fast, like a giant piece of flat-packed furniture,” said Andrew Lawrence, a timber specialist at Arup, which designed Haut.

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