Courtesy of new plywood technology, timber skyscrapers are going to become a more frequent sight around the world. They create lower carbon emissions and require less time to build.
Surrounded by farmland and with a population of under 10,000 people, the Norwegian town of Brumunddal might seem like an unlikely setting for a record-breaking high-rise. Soaring above Mjøsa lake, the 280-foot-tall Mjøstårnet tower (pictured above) became the world's tallest timber building when it opened last year.
The 18-story structure contains apartments, office space and the aptly named Wood Hotel. And beyond putting a small town on the world map, it has added to a growing body of evidence that timber can provide a sustainable alternative to concrete and steel.
The secret to these 'plyscrapers' is due to a new way to create plywood, and it involves laminating boards of wood together with glue at 90-degree angles before pressing them together under the immense pressure and steam of industrial wood presses. It's known as cross-laminated timber (CLT).
“This technology has changed the whole face of timber as a construction material,” said Roma Agrawal, the structural engineer who built The Shard in central London, to The Economic Times. “It’s a huge leap forward in terms of strength [paired with] massive advances” [in fire safety.]
Buildings like the Terrace House in Vancouver (19 story), the HoHo in Vienna (24 story), the Ascent in Milwaukee (25 story - twilight rendering featured), and the Mjøstårnet in Norway - the tallest wooden tower in the world, wouldn’t be possible without CLT and mass-timber technology.
Whilst it may seem counter-intuitive to chop down trees to create new buildings, the reality is that if felled at the right age they have reached their maximum capacity to sequester carbon. The CLT process then locks in the already sequestered carbon and holds it captive.
Daniel Safarik is with the Council on Tall Buildings and Urban Habitat in America. He sees mass timber construction as key to housing the world’s ever more urban population.
"We’re going to have to be thinking about how do we build sustainably, and to have a material that could allow us to build in a high density safely and which locks up carbon seems like a win, win, win," he says.
Trees sequester carbon dioxide and the wood holds it captive - even when made into lumber and used to create a skyscraper.