Tokyo to build world’s tallest timber tower

Story highlights

New super strength products such as engineered bamboo are making timber a more popular building material

Experts say wooden buildings have a positive psychological effect on people

CNN  — 

A Tokyo skyscraper is set to become the world’s tallest wooden building. Japanese company Sumitomo Forestry says its 1,148-feet-tall timber tower will be completed in 2041, to mark the 350th anniversary of the business that year. The W350 tower will cost an estimated 600 billion yen ($5.6 billion) to build.

The 70-story tower will be a hybrid structure made from 90% wooden materials. A steel vibration-control framework will underpin the design – an important feature in a city where earthquakes are frequent.

An artist's impression of inside the W350 tower in Tokyo.

Green balconies will populate the skyscraper’s exterior, connecting the building to its environment.

“The aim is to create environmentally-friendly and timber-utilizing cities where (cities) become forests through increased use of wooden architecture for high-rise buildings,” the company said in a press release.

The Japanese government is trying to encourage more developers to use wood. In 2010, it passed the Promotion of Use of Wood in Public Buildings Act, which required all government buildings up to three stories high to be constructed with wood, or to utilize wood.

Spreading like wildfire

It isn’t only Japan where wooden skyscrapers are putting down roots. Over the past decade, there has been a global explosion of timber towers, either built or proposed, every one seemingly a recorder breaker in some respect.

Canada currently holds the world record for the world’s tallest timber tower, at 164 feet tall. The 18-story Brock Commons Tallwood House, a student residence, topped out last year at the University of British Columbia (UBC), in Vancouver, and has been dubbed the world’s tallest “plyscraper.”

Before it topped out, The Treet in Central Bergen, Norway, was the world’s tallest timber. It took that title in 2014 from the 10-story, 104-feet-high Forte residential block, which overlooks Melbourne’s Victoria Harbour and was completed in 2012.

Oakwood Tower would be London's tallest wooden skyscraper.

Last year, the Cube, a 109-feet-high apartment block in London’s Shoreditch, became “the tallest cross-laminated timber structure in Europe,” according to its developers.

Meanwhile, the Oakwood Tower is a proposed joint project by PLP Architecture and Cambridge University’s Department of Architecture. It’s been called an experiment in pushing the frontiers of building with wood.

The 80-story tower, if given the green light for construction, will be made of timber – making it London’s first wooden skyscraper and the tallest wooden structure in the world.

Branching out

New types of ultra-strong timber are partly driving the trend.

Cross-laminated timber, for example, sees thin layers of wood placed across one another at right angles, and laminated with fire-resistant glue to create a stronger weave.

This floating wooden pavilion is the Pavillion of Reflections in Zurich. It was revealed as part of Manifesta, an annual contemporary art biennial.

But it’s bamboo – a material that has been used in Asian construction for centuries – that most interests Ramage.

“We’re working on engineered bamboo,” says Ramage. “We can take the walls of bamboo tubes, cut them up into rectangles and glue them into big slabs.

Kevin Flanagan, a partner at PLP architects, adds that in the future he can imagine the industry genetically modifying wood to make it even more conducive to high-rise construction.

London’s burning?

Obviously, when it comes to wooden buildings, there’s one burning question.

Ramage says Oakwood Tower – which will be an extension of the Barbican Center in Central London – will exceed the fire standards of regular steel and concrete buildings.

“There is a huge perception problem,” says Ramage. “Timber doesn’t burn in the way the public imagines.

The "Sida Vid Sida" ("side by side") wooden building is a proposed project by Swedish architects White Arkitekter.

Wood, he says, burns predictably. Therefore, fire engineers can calculate how large a block of wood is needed to provide a protective layer to sustain a building for a certain period of time.

“All buildings over a certain size need to have sprinklers and active fire suppression systems – irrelevant of whether it’s wood, concrete or steel,” he adds.

A series of blazes at Dubai skyscrapers in recent years have highlighted that it isn’t just timber buildings at risk of catching fire.

Aren’t we meant to be saving the rainf