Despite the hype, B.C. still has just two wooden highrises
Douglas Todd
The Vancouver Sun
Mass-timber towers, like UBC’s 18-storey Brock Commons, are called the best way to reduce the carbon emitted by concrete highrises. Why are there so few of them?
The dream of greener buildings is why an international buzz was created when designs were announced for a 40-storey wooden building, dubbed Canada Earth Tower, at 1745 West 8th in Vancouver. But it’s been stalled. Photo by Delta Group and Perkins and Will /PNG
During heated debate over the Broadway Plan, Vancouver city council responded with a concerted effort to pave the way for more mass-timber highrises.
But despite years of talk about such structures, only two have been built in B.C.
Stung by complaints that the hundreds of highrises intended for the Broadway corridor would be conventionally made of concrete, which produces massive greenhouse gas emissions, council scrambled in May to make its dramatic densification push fit with its 2020 climate plan, which promises to reduce carbon emissions in Vancouver by 40 per cent by 2030.
Sean Pander, manager of green buildings for the city, said the Broadway Plan stipulates that “new construction should explore innovative low-carbon building technologies, such as mass-timber construction” and “where possible, allow simplified building forms to facilitate the use of mass timber and other low-carbon building materials.”
Prodded by Broadway Plan opponents such as sustainability specialist Paul Morris, Vancouver council decided in May to change the building bylaw to allow mass timber outright up to 12 storeys, a hike from the previous cap of six storeys. Pander said council’s climate goals will ultimately “increase demand for mass timber buildings, like the 18-storey mass-timber student-housing building at UBC.”
Today, 12 storeys remains the city limit for a mass-timber structure, unless a builder can “demonstrate they meet the safety requirements of the building bylaw” through a so-called “alternative solution.”
Mass-timber towers, like UBC’s 18-storey Brock Commons Tallwood House, are often held up as the best way to reduce the immense amounts of carbon emitted by concrete-and-steel highrises in their construction and operation.
Brock Commons, a student residence, was the world’s highest contemporary wood highrise when it was completed in 2017 to many awards. Even though most of it, except for a common area and some exterior cladding, doesn’t look or feel particularly woodsy, Vancouver architect Michael Geller joined many in imagining it as a big part of the future of urban density.
But that was five years ago. Such towers remain rare, despite so-called “cross-laminated timber” technology being around for a couple of decades.
Brock Commons, at 53 metres (174 feet), is no longer the record holder for height. In a small town in forested Norway, a higher all-timber tower, Mjøstårnet, recently went up to 85.4 metres (280 feet). And a 87-metre (284-foot) luxury residential tower named Ascent MKE is nearing completion in Milwaukee, Wisconsin.
But the existence of three 18-storey-plus timber highrises in isolated locations is set against cities around the world packed with hundreds of thousands of concrete and steel highrises, which are generally defined as structures of 12 storeys and taller.
Metro Vancouver has more than 1,000 concrete highrises. And there are countless more coming, including in the city of Vancouver as its politicians try to increase population density in the core to ostensibly decrease commuting times and carbon fumes.
The big problem with concrete is the cement needed to make it, says Morris. When cement is created by roasting limestone and various compounds at high temperatures, it releases a tremendous amount of carbon. Chatham House, a British think-tank, says the annual production of four billion tonnes of cement causes eight per cent of world carbon emissions, much more than the airline industry’s two per cent.
UBC’s Brock Commons Tallwood House, a student residence, was the world’s highest contemporary wood highrise when it was completed in 2017 to praise and many awards. Why have so few, including UBC, followed its lead? Photo by NICK PROCAYLO /PNG
Timber pillars reduce carbon dioxide emissions
Given the radically lower carbon advantages of wood, why are so few highrises made of this sustainable material?
Wood is a fifth the weight of concrete, which reduces the energy used for its transportation and cuts the need for massive foundations. Wooden buildings also require less insulation and less mechanical ventilation, says Morris.
Importantly, since the thick pillars in tall wooden buildings are made of trees, they retain carbon dioxide captured from the atmosphere as the trees grew.
The carbon-sequestering properties of wood confer a huge environmental benefit. The Journal of Sustainable Forestry estimated that substituting wood for current construction materials would annually save 14 to 31 per cent of global carbon dioxide emissions.
And many people simply find wood more esthetic. A New Yorker writer described Norway’s 18-storey wood building as “seductively calming” and its exposed five foot by two feet beams seemed “smooth, resonant, and much less cold than a metal pillar would have been.”
There are even peer-reviewed studies led by Cornell University’s Christina Kelz and others that have shown children who attend school in educational buildings with wooden walls and furniture have lower heart rates.
This kind of research encouraged the B.C. Forests Ministry in 2021 to put taxpayer money into a mass-timber demonstration program, which can be found at naturallywood.com.
The dream of greener buildings is also why an international buzz was created more than three years ago when a rezoning application was announced for a 40-storey wooden building, dubbed Canada Earth Tower, at 1745 West 8th in Vancouver. But it stalled for years as council reviewed the Broadway Plan. Now that the plan for much taller towers in the area is approved, says Vicki Su of Perkins & Will architectural firm, the Earth Tower project will be re-evaluated.
B.C’s forestry innovation website boasts “mass timber has been used in over 370 buildings in B.C. since 2007.”
But there remain only two completed mass-timber highrises in the province, says Sukh Johal, senior manager for Wood Works B.C. and the Canadian Wood Council.
They are Brock Commons and Tallwood 1, a 12-storey residential-commercial building in the Victoria suburb of Langford, said Johal. A 10-storey wood building, called the Capstone, is under construction in Kelowna.
Several other wood tower plans have been made public in the past few years, Johal says, but it’s impossible to summarize whether they will get final approval, maintain financial feasibility or otherwise go ahead.
B.C.’s forestry innovation investment website says two of the major would-be projects are a 10-storey office building planned by BentallGreenOak in Vancouver’s False Creek Flats and Westbank’s 21-storey timber residential building, dubbed Prototype, for Vancouver’s Mount Pleasant.
Given such a short list, the question remains: Why are there so few mass-timber highrises in Canada and especially B.C. — given that two thirds of the province is covered in forest?
There are many reasons that visions of timber highrises have been so slow in coming to reality. Some are psychological. Some are technical. The mass-timber industry says both concerns can be overcome.
Another #fire in #Vancouver during the construction of a four storey #wood building. When wood advocates say wooden builds are safe, think twice. Buyer be aware.
Overcoming old fears of fire
“Another fire in Vancouver during the construction of a wood building,” began a 2020 Tweet by Michael McSweeney, then-head of the Cement Association of Canada. “When wood advocates say wooden builds are safe, think twice. Buyer be aware,” McSweeney went on, attaching images of a blazing wooden apartment building.
It was one of many times the recently retired head of the Cement Association has raised the alarm about fires in wooden buildings.
Cautious fire chiefs have also for years raised worries about whether wood buildings are too vulnerable. But attitudes are shifting and technology is advancing. Researchers are finding, as are fire officials, that glue-laminated timber beams tend to merely char on the outside two or three centimetres, a bit like tree trunks in a forest fire.
Still, fear of fire appears to be the key reason Canada’s National Building Code generally restricts mass timber buildings in the country to 12 storeys, says Peter Moonen, sustainability manager for the Canadian Wood Council.
Most developers hold back on erecting mass-timber highrises because they’re waiting to see what happens when others do it, says Peter Moonen of the Canadian Wood Council. Photo by Submitted by subject /jpg
For Brock Commons, UBC officials obtained dispensation to go above 12 storeys by making a strong site-specific case, according to Moonen.
Regrettably, Moonen said, the developer of Brock Commons had to address fire chiefs’ fears by “encapsulating” virtually every one of its interior walls in three layers of Gyproc drywall, which is especially fire resistant.
“It added a lot of mess and a fair bit of cost,” said Moonen, although it did help the UBC project get erected on time and on a budget similar to a concrete and steel tower.
The good news, Moonen said, is that lumber officials, firefighters and insurance brokers are increasingly taking part in staged demonstration burns of timber structures.
Len Garis, former president of the Fire Chiefs Association of B.C., has been among those defending their safety.
That said, UBC is building the second phase of Brock Commons’ student residences out of conventional concrete. Asked why, a spokesperson said Tallwood House was a “unique demonstration project.”
Even though UBC’s Brock Commons Tallwood House (background right) was built in 2017, the new residences of Brock Commons Phase 2 are being constructed with concrete.
Possible obstacles to mass-timber highrises
Lack of innovative spirit
Most Canadian builders are not famous for their sense of adventure, says Moonen.
Most developers hold back on erecting mass-timber highrises, he says, because they’re waiting to see what happens when others do it.
“It’s maybe why Canadians are satisfied with bronze medals,” Moonen says.
He also regrets that architecture, trade schools and others don’t show leadership in teaching students how to work with cross-laminated timber, including its special ability to be accurately machined. “It’s like offering a chef’s course and not teaching about how to cook with vegetables.”
Is timber ‘too’ light?
Although one huge advantage of wood is that it’s far lighter than concrete, Lloyd Alter, an architectural writer who teaches sustainable design at Toronto Metropolitan University, points out that engineers added concrete to the top floors of Norway’s wooden highrise because it was next to a windy lake. The wooden structure was in danger of swaying too much, causing residents to feel nauseated.
There is little downside to plantation forests, which are managed forests in which the trees are planted for the maximization of wood fibre, says Lloyd Alter, architect, real estate developer. jpg
The lightness of mass timber is also one of the reasons wooden highrises are still made with concrete foundations, albeit of far less mass than for conventional construction.
How does the cost of mass-timber highrises compare?
“Cross-laminated timber is not cheap,” says high-profile Seattle architect Matthias Olt. “It is more expensive per unit than steel or concrete. The savings comes in reduced labour costs. The number of construction workers required on-site is cut in half.”
Wood buildings, he said, also last longer.
Why go over 12 storeys anyways?
Alter is among the architects and planners who believe it’s unwise to go higher than 12 storeys, whether a building is of concrete or wood.
Several researchers, notably Edinburgh Napier University’s Francesco Pomponi, have found buildings under 12 storeys produce less carbon emissions and create better communities.
Despite protests, forests can be grown in sustainable ways
More than 18,000 trees were required to build the Mjøstårnet in Norway, where the country’s pine and spruce trees tend to be smaller than the fir and hemlock of British Columbia.
While some environmentalists don’t want to see any old-growth trees cut down to produce buildings, many others, including Alter, say there is little downside to plantation forests, which are managed forests in which the trees are planted for the maximization of wood fibre.
As Moonen, who lives on the green slopes of the Sunshine Coast mountains, says: “We should be coming up with the brightest and best uses for what we grow in our own backyard.”
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@douglastodd
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