The truth about mass timber: B.C.’s favourite green building material isn’t always a climate hero

The audience of dedicated urbanists at Vancouver’s Robson Square Theatre was startled earlier this year when the first speaker at a debate about mass timber—the new construction material composed of slats of wood glued together, which B.C. has been promoting vigorously—said it isn’t the for-sure climate-change silver bullet that everyone likes to think it is.

Adam Rysanek, a UBC professor of environmental systems who specializes in energy efficiency, poked hard at the assumption that, because everyone thinks of mass timber as just wood—a plant! that comes out of the ground!—it must be natural and environmentally friendly and surely better than concrete.

But Rysanek kept making the point over the next hour of the Urbanarium debate that those ideas are not fully proven. A study he cited, which aimed to factor in all the uncertainties of carbon emissions in different types of building materials, found there is not a clear answer yet about the differences between mass timber and concrete.

“The resounding conclusion was that the two [sets of results from concrete and mass-timber buildings] overlap so significantly that you cannot say definitively, without ambiguity, that a mass-timber building produces lower carbon than a reinforced concrete building,” Rysanek said, pointing out that mass timber isn’t just wood. It takes a lot of heavy-duty glue and special metal fasteners to create it, along with coverings to make mass timber less vulnerable to the plagues of building—fire, water, insects.

Rysanek’s brake-pumping argument is one that hasn’t had much airtime in the last decade, as governments of various stripes in B.C.—along with environmental groups, sub-groups of architects and engineers interested in climate-change mitigation, and people in the general public—have become entranced by the idea of more tall buildings made entirely of wood instead of concrete.

Now, as the NDP government has pushed aggressively to encourage its use, permitting mass-timber buildings up to 18 storeys in the province, many people who produce or study buildings are taking a closer look at mass-timber construction, asking if it really works for every project, every climate, every design.

Even the man who has been B.C.’s prime evangelist when it comes to mass timber (a term he invented), Vancouver architect Michael Green, says no one should automatically assume that a piece of mass timber, or a whole building of same, is always the answer.

“There are times when wood is not the lowest-carbon solution,” he says. “It’s not great to use wood for everything. If I can do one part with a smaller steel beam, I’ll do that.”

But Green, who has given TED talks on the subject, has projects going on in Europe and the U.S., including a building for Google in Sunnyvale, California, the archives for the Royal B.C. Museum in Victoria, and a 35-storey tower in Paris, is still a fervent believer in the ultimate benefits of mass timber for the climate, for livable buildings, for quality of life.

“Nature always wins. Natural materials are the best way to build for human health, human stress and for the planet’s well-being. All species on earth, evolution teaches, are driven to find the lowest-energy solution to thrive and prosper, except for humans.

My positive belief system is that at the end of the day, we still are just part of this greater planet and we will find a path forward.”

In this next phase of mass-timber construction, it appears likely that a lot of people will take a closer look at those assertions to figure out when building with mass timber is a benefit and when it’s a big hassle that doesn’t notably improve anything.

Australian Philip Oldfield, an architecture professor and head of the School of Built Environment at the University of New South Wales, says people need to examine carefully what produces real energy-efficiency benefits and what doesn’t.

He argues passionately that assessing real impacts on greenhouse-gas emissions is important as the world heads into a massive building boom. Estimates he cites suggest there will be 230 billion square metres of new construction by 2060, which would add 120 billion tonnes of greenhouse gas emissions to the air if status-quo building techniques prevail. But he argues against just jumping on mass timber as the easy solution.

“I think there’s quite robust evidence that mass timber is lower embodied carbon than concrete,” he tells BCBusiness. “But our research has found this benefit is actually quite modest at the building scale—maybe 10 percent. Just switching to mass timber alone will not solve the climate crisis in the built environment. I also think an efficient concrete building can be better than an inefficient timber building.”

He also notes that, while regions like B.C. and—in particular—France are encouraging mass-timber construction, many others aren’t. And some big areas of the world are profoundly dubious about it.

“While mass timber has made a splash in some locations, globally it’s still a very minor player and the global construction market still has a huge path dependency on concrete, especially in Asian and Africa where construction is highest.”

Oldfield’s recent article in The Conversation noted that, if builders really want to reduce carbon emissions, there are many often little-noticed changes that can make an outsized difference. Putting in long-lasting hardwood floors is a huge improvement over carpets, which have to be replaced every 10 years. In the model they developed, that alone reduced the carbon emissions in a hypothetical office building by 625 tonnes.

A study his team did found a way to reduce embodied carbon in buildings by 45 percent, but that required a much bigger re-design: straw insulation in the walls, fewer windows, more recycled material.

He acknowledged that “many of the moves we made are far more radical than common industry practice.”

Radical change is not something the building industry embraces. Developers, with sometimes hundreds of millions of dollars on the line, tend to prefer sticking with known techniques and designs to minimize risk. They’re cautious about jumping to wholesale conversions to mass timber, let alone the other strategies Oldfield has alluded to.

But there is still some interest in experimentation. Wesgroup, a major Vancouver-based developer, has a senior executive dedicated to exploring the possibilities of building more with mass timber.

But that executive, Graham Brewster, is cautious. And frustrated, saying municipal and provincial policies aren’t helping a move to the new possibilities.

“In the current development context, the risk is not worth the reward, as it requires innovation on several fronts. And if you try to fit mass timber into current policy, it doesn’t work,” says Brewster, who is senior director of development at Wesgroup. “What is needed is an alignment of construction technology with development.”

He says governments that want to promote mass timber need more pilot projects so those in the industry can see that “the benefits are real and attainable.”

“Until we see that, innovation is going to continue to be perceived as overly risky, not rewardy.”

Brewster also says it works best with certain types of buildings—mid-rise, seven to 18 storeys (with 12 as the optimum), minimal setbacks, a simple stacked form.

Michael Green, who is doing a 54-storey tower in Milwaukee, Wisconsin, disputes that—and is critical of the local development industry for not embracing mass timber more enthusiastically.

“The development industry is so set in its ways about concrete,” he says. “The building community is still resistant to changes.”

But, like Brewster, he also faults slow-moving, locked-in-their-ways governments for not doing more.

“Vancouver is very good at stifling good architecture,” he adds ruefully.

The province is insisting everything is full steam ahead and things are going well. It has a mass-timber action plan, released in July 2024. It supported a conference in September called Woodrise that brought together people experimenting with wood construction techniques as part of B.C.’s effort to position itself as a global leader in the sector.

A ministry spokesperson says about 450 mass-timber buildings have been completed or are under construction, noting that is 20 times more per capita than the rest of North America. It’s about half of the 800 mass-timber buildings that the federal government says exist nationally.

And, while B.C. hasn’t gone as far as France, which mandates that 50 percent of any new public building has to be built with mass timber or other natural materials, this province requires any public building to use mass timber “whenever feasible,” a policy that has resulted in 41 successful projects.

One thing no one has worked out yet, though, is the supply.

What? you say. But B.C. is filled with wood. Surely supply is the last thing this province needs to worry about.

As it turns out, there is only one mass-timber producer in B.C.—the Kalesnikoff Lumber Co. facility in Castlegar. Another company that had been operating a factory in Penticton, Structurlam, filed for bankruptcy in April 2023.

While Michael Green says Kalesnikoff is making the “best product in the world right now,” it’s not enough. Many builders are getting their mass timber from elsewhere.

It’s something that you’d think the province might put some muscle into changing, especially given the dire state of the forestry industry as a result of U.S. tariffs.

So far, no word on that.