When you walk into the Earth Sciences Building at the University of B.C. in Vancouver, you will see a five-storey staircase made out of a special kind of wood.
It’s known as cross-laminated-timber or mass timber.
The building, completed in 2012, uses this unique product as one of its key components in the north wing of the building. That was done purposefully, says Penny Martyn, the university’s green-building manager.
“We do like to use wooden mass timber because it’s got a low embodied carbon compared to other products and because it’s more locally sourced,” she said. “And it’s a beautiful product too that people enjoy — the warmth and the naturalness of wood. So, we do really like to have wood buildings.”
Wooden buildings, while not a new concept, are part of a larger change the construction industry is making to build more sustainably.
“[The construction industry] is still based largely on past paradigms of material performance that value strength above all else and doesn’t always take into account the environment,” said Joseph Dahmen, professor of architecture and design at UBC’s School of Architecture and Landscape Architecture.
“We still have largely a culture based on materials like concrete and steel. Until we actually start adopting different sets of values and priorities, I think that we will still be in a real challenge to address the current climate crisis.”
Construction is changing
Buildings are responsible for 37 per cent of global carbon emissions. When engineers think about the climate crisis and how it relates to buildings, there are two types of carbon emissions they consider: embodied carbon emissions and operational carbon emissions.
One of the major ways the construction industry is changing is by focusing on the carbon emissions from building materials, after years of focusing only on making buildings more energy-efficient once they are built.
The carbon emissions from building materials, known as embodied carbon, are the emissions accrued during construction, explained Dahmen.
“The materials of a building have impact that occur the day the building opens. They are all upfront,” he said.
Buildings have a second type of emissions known as operational carbon, which includes the energy used to light, heat and cool buildings. These energy sources can be renewable, like electricity, or non-renewable, like natural gas.
“For many years, we thought to reduce the energy to heat building almost at all costs,” he said. “We wanted to get down all that energy used to keep buildings comfortable, and that was a good idea, but the trouble is we use a lot of really toxic materials to do that.”
Materials like polystyrene foams that have been used to insulate buildings have actually caused damage to human and environmental health.
“We’ve been really preoccupied by making more efficient systems and improving insulation, and that’s all really good,” Dahmen said. “But it’s only in the last few years that we’ve begun to really account for the impact of the building materials themselves.”
Another reason architects and building designers are turning their focus to more sustainable building materials is that, after years of focusing on energy efficiency in buildings, they realized that focusing on energy will not really solve the climate problem, says John Straube, professor of engineering and architecture at the University of Waterloo’s department of civil and environmental engineering.
“It’s not energy that’s the problem, it’s carbon that’s the crisis,” he said.
Straube added that leading-edge designers and builders are moving beyond thinking about just the operational carbon of the building which includes lighting, heating and cooling of the building and moving towards building with low carbon content materials.
“The next challenge is how do we build buildings without a lot of carbon,” he said.
In addition, all those years put towards reducing the operational carbon of a building haven’t gone to waste. As the operational carbon of a building is reduced, the more significant the embodied carbon becomes, said Martyn.
“Now, we want to reduce [embodied carbon] as well. We’re in the early stages of figuring out how to do that,” she said.
Sustainability and good design are a perfect match
Striking the balance between both kinds of carbon emissions can be tricky, said George Benson, a green-building expert with the Vancouver Economic Commission. For the total emissions of a building to be reduced, or achieve net-zero, It is important that both sources of emissions come down at the same time.
“If you want to have a really well-insulated building that uses relatively little energy, well, you’ve got to use more building materials for that,” he said. “But if you want a building with less carbon than an average — like less carbon embodied or embedded in it — then you need to probably use fewer building materials or building materials of different types than what you previously used.”
Benson added that more data and modelling are needed to determine what works best.
“What are the different archetypes? What are the different design standards? What are the looks and feels of a building that has reduced embodied carbon by 40%?”
Research is being done on new types of materials such as mass timber, mushrooms, strawbale, and hemp that can be used as low-carbon building alternatives to traditional materials such as steel, aluminum, and concrete.
“For a long time, it was a choice between either you wanted a well-designed building or you wanted a sustainable building. And now we’ve recognized that’s a false dichotomy or distinction.” Dahmen said.
“We can have really well-designed buildings that are also sustainable and actually engaged in positive relationships — not only with the natural environment, but the people that live in them and work in them are healthier and more productive.”
Building a well-designed and sustainable building starts from the ground up.
Benson said that sustainability conversations are happening earlier in the building design process including conversations about the total lifecycle of building materials, reuse, and the circular economy are “exciting” things happening in the industry as it moves towards a more sustainable future.
“Before they even stick a shovel in the ground, they’ve already designed a different way of thinking about the building, of paying for the building, of maintaining the building, of who’s gonna be in the building — all those things are taken care of,” he said.
UBC’s Green Building Action Plan, developed in 2018, is a guide for the construction and development of new buildings on campus to “make net positive contributions to human and natural systems” by 2035.
The plan covers eight areas: energy, water, materials and resources, biodiversity, health and wellbeing, quality, climate adaptation, and place and experience.
“If we can reduce [the emissions] for, first of all, our new buildings, but also our existing buildings, that can make a really significant difference,” Martyn said. “new buildings should definitely be aiming towards not emitting anything.”
At the end of the day, these changes in the industry depend on the people in it. As the people in the industry change, the industry itself would change.
The demographics are already changing from old, white and male to reflect the broader Canadian society, Benson said.
“One of the really cool trends in the construction industry which I think will help generate sustainability because lots of people of colour, for example, and women who are entering the industry are like ‘No, no, we need to do things differently. You can’t do things the way we’ve always done,’” he said. “That trend is really crucial.”
In addition, as it becomes more obvious that society cannot ignore the effects or consequences of climate change, more people are interested in sustainable buildings, Straube said.
“There have been people concerned about sustainability in professional architecture, since at least the 1770s,” he said. “And It’s just that the percentage of designers and owners who are concerned about this has grown every year, and it’s reaching a critical mass now, as every new generation of designers comes for it.”
For Dahmen, these changes make the field of construction better positioned to meet the challenge of climate change.
“I think it’s a really exciting time to be an architect because we are just now recognizing the need for this shift,” he said.
“If we’re to confront climate change, we really can’t do it without changing the way we approach our buildings. The way we design and build our buildings. Really.”