As the impacts of climate change continue to make temperatures more extreme and housing gets more expensive, the way we approach construction has been slowly — but surely — innovating.

One such innovation is mass timber construction, which means building with wood as the primary material. With projects built using mass timber being able to reduce carbon pollution during construction by up to 45 per cent, using wood to build our cities, including homes, schools, and infrastructure, has a host of environmental benefits.

To help us gain a better understanding of mass timber buildings, we partnered with Forestry for the Future to speak with award-winning architect and Principal at Urban Arts Architecture Inc., Shelley Craig.

McFarland Marceau Architects Ltd. (KK Law/naturallywood.com)

Building more sustainably for more housing

The effects of climate change have made construction even harder — it's freezing work in the winter and likewise becoming extremely hot in the summer. With mass timber panels, Craig says there are many elements you can prefabricate in a controlled environment and ship to sites — especially for housing models that recycle similar designs.

“Everyone started talking about these '3D printed houses,' which are done in factories and mass produced. With the help of building information modelling or computer-aided design drawings, there’s no reason the same can’t be done with wood,” Craig tells blogTO.

Craig also points to the stick frames that comprise many single-family homes, and how easily they can be converted into multi-unit dwellings. With mass timber buildings, she says, it’s so easy to modify — you can slot panels out to adapt your build to what you need with little waste.

Squamish Lil’wat Cultural Centre, Formline Architecture and Toby Russell Buckwell & Partners (Michael Bednar/naturallywood.com)

“It's really hard to build right now because it's hard to get materials, it's hard to get people that are trained to build. So how can you start to take some of those into the factories, into controlled settings … [using wood is] set up as a slam dunk for use as a primary building material.”

Building code barriers

Building codes in some provinces have traditionally been a barrier to building taller with mass timber. In BC, for example, wood construction was at one point restrained to four storeys. These limitations have impacted the ability to build more of our homes — like apartments and condos — with wood.

“We did a lot of research work to figure out how we can build taller and higher in wood,” says Craig.

Through this research project, Craig and her team identified cross-laminated timber (CLT) panels as a “miracle material.”

Brock Commons at UBC, Acton Ostry Architects (Brudder Productions/naturallywood.com)

For those unfamiliar, CLT panels are created using multiple layers of wood stacked and glued with their grains in an alternating 90-degree orientation. This creates wood slabs that have a better strength-to-weight ratio than traditional materials, with added benefits.

Craig and her team studied how we could build taller and higher buildings using CLT, and the findings from this project resulted in BC's building codes changing, and, subsequently, the rest of Canada followed suit.

Now, buildings can be constructed up to 12 storeys in mass timber — opening a world of possibilities for how building with wood can help address Canada’s housing crisis, both from an environmental and affordability standpoint.

The benefits of mass timber buildings

There are plenty of benefits of using mass timber buildings versus traditional building materials. Because trees absorb carbon, wood products like lumber can lock that carbon in. This means that wood-frame buildings are an effective way to store carbon long-term.

Using wood as a building material is even more sustainable when it comes from sustainably managed forests. This means that there is a long-term plan in place to keep the forest healthy and more resilient to natural disturbances like pests, disease, and wildfire which can cause greenhouse gases to be released back into the atmosphere.

Canada’s forest sector is a global leader in sustainable forest management. Not only does Canada lead the world in third-party forest certification, managing 36 per cent of the world’s certified forests and more than twice the area certified in any country, but less than 0.5 per cent of forests designated for harvesting are actually harvested per year.

Brock Commons at UBC, Acton Ostry Architects (Michael Elkan Photography/naturallywood.com)

Canadian foresters operating on public land (where 90 per cent of Canada’s forests are located) are required by law to replant every tree, planting 400 and 600 million seedlings annually, all while promoting wildlife habitats, biodiversity, and water protection.

When wood from Canada’s managed forests is used in construction, it promotes a sustainable, circular approach to establishing our future cities. And, as a bio-based material and renewable resource, wood offers benefits that other building materials don’t. Gravel and sand are a lot harder to regenerate, and concrete and steel are more carbon-intensive.

There are also cost-saving benefits to using wood in construction. Not only is it less expensive to heat and cool mass timber buildings, but construction is less expensive as it requires less time than alternatives.

Examples of mass-timber buildings

Brock Commons at UBC is an example of mass timber's potential in Canadian construction. The maximum allowable height for this building type was six storeys in 2017, however, Brock Commons was completed under a site-specific allowance. This made it the world’s tallest mass timber building at the time, standing 18 storeys tall.

“It's considered a non-precedent setting building,” says Craig. “But it really does set a precedent, because it shows you know what you can do [with mass timber].”

Radium Hot Springs, Urban Arts Architecture Inc. (Best Impressions Photography)

Another innovative mass timber build is the Radium Hot Springs Community Hall and Library, which is one of the first dowel-laminated timber (DLT) buildings Craig has worked on. Unlike CLT, which uses adhesives to bind its panels together, DLT uses the friction of a wooden dowel, making this small community building even more sustainably built.

“You can basically recycle it completely if you want to afterwards, and turn [the panels] into something else,” says Craig. “You can take the building apart, almost like a large set of Lego, and use the panels in another project.”

Looking to the future of mass-timber buildings

While there’s still a way to go, Craig reassures that there is progress being made by people on both a structural and architectural front, working to build higher.

Looking to the potential of mass timber construction and how easily most elements can be prefabricated, Craig envisions a world where you can pick the logs, pre-make the panels, and pick them slotted, pre-drilled, sized, and ready to be put together.

“There's a lot of talk about this in terms of standardization: is there the ability to implement repetitive housing models? Whether it's an industrial model that prebuilds in a factory and transported to a site or flat pack scenario you could potentially pick up at Walmart, I think we’re in an interesting chapter [with mass timber].”

Acton Ostry Architects (KK Law/naturallywood.com)

Right now, Craig’s focus is on reducing the impacts construction has on climate change, with her firm looking at how to better use an entire log to ensure there’s no waste.

“At a mill, they can analyze [a log] and optimize it for two-by-fours, two-by-sixes, posts, whatever it might be. And there is a lot of research being done on ways to maximize the leftover wood, like offcuts and 'waste' in building as well. The forest sector, alongside architectural and engineering firms, is looking into this. How [can we] use the bark and those smaller pieces? Can they be ground up and used as wood insulation? It's really the 'whole-log approach'.”

For Craig, everyone’s job is about climate change, regardless of what industry you’re in. With construction contributing over one-third of global energy consumption and emissions, she wants to reduce her impact where she can.

“To quote many Indigenous nations: what is the seven-generation solution for all components of construction? What happens to your materials? What's the circular economy approach? How do we look at reusing things, or reducing our carbon footprint? I think our forests, and building with wood, have a strong role to play in answering those questions.”

To learn more about the implications of mass timber, and how Canada’s forests can promote sustainable living, check out Forestry for the Future.