The drive for sustainability in tall buildings has led to increasing interest in the use of timber as a major structural element, even in very tall buildings.
Heightened environmental concerns have dovetailed nicely with the development of mass timber construction, much of which uses cross-laminated timber, or CLT.
Those concerns have led to an organization called the Council on Tall Buildings and Urban Habitat to undertake a global audit of tall buildings that are made mostly of wood, or so-called hybrid buildings that combine timber with steel or concrete.
The list is impressive, showing 49 buildings that are completed, under construction or proposed. The list shows nothing of six storeys or less for two reasons.
The council and its members are, after all, interested in tall buildings. Conventional "stick-framed" construction can rise as high as six storeys in some countries. Those lower buildings only rarely used mass timber.
The audit shows that 21 timber buildings with a height of more than 50 metres will be completed in 2019.
France, Austria and Norway are scheduled to become home to the tallest wooden buildings. The tallest, at 35 storeys, will be the Baobab building in Paris. It was designed by Michael Green Architecture, a prominent Vancouver firm. It will be a mixed-use tower of hybrid timber-and-steel construction and should be completed in 2019.
In Canada, the 18-storey Brock Commons, on the University of British Columbia's main campus in Vancouver, is newly completed. It's a residential building housing 404 students in 272 studio apartments and 33 four-bedroom apartments. The building was designed by Acton Ostry Architects.
Also in Vancouver, work will soon be underway on Terrace House, a hybrid that will use wood, glass and concrete. It will stand 19 storeys, putting it one storey up on Brock Commons.
I'm not sure how developers and architects feel about some of these tall buildings, but the popular press reports on heights as though it were reporting on a horse race. So, Brock Commons and Terrace House are in the news. In the meantime Origine, in Quebec City, which will top off at 13 storeys later this year, gets little ink. Neither does Arbora, in Montreal, which was finished last year and is just eight storeys tall.
The developers who commissioned these buildings using mass timber are acutely aware that the people who occupy the buildings are influenced by increasing knowledge of how buildings affect the occupants.
Greener buildings built from natural materials and using natural finishes make for happier and more productive employees, so companies are looking for those attributes when they decide to move into a new space.
The runaway success of the LEED certification system did a lot to raise the environmental awareness of employees and employers alike. So it's not surprising that there is interest at all levels in using mass timber construction.
Wood building systems are being used in net-zero-energy structures, with many advances coming from California.
In recent years the International WELL Building Institute has developed a standard that has become an influential third-party certification system.
It's based on scientific and medical research and includes seven areas of building performance.
They are daylighting, water quality, psychological impacts, physical and sensory experiences, and human inputs like air, food and exercise.
Last year, the U.S. Green Building Council noted that the WELL Building Standard could become more popular after research showed that 79 per cent of U.S. building owners believe that healthier architecture and operations improve employee satisfaction and engagement.
All of that fits nicely with the increased interest in mass timber construction.
Just 49 tall timber buildings worldwide hardly constitutes a trend. But the inescapable fact is that those buildings wouldn't be built using mass timber if the developers who commissioned them weren't aware that consumer demand is driving interest in wood technology.
Korky Koroluk is an Ottawa-based freelance writer. Send comments to email@example.com.