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Construction waste in Canada accounts for close to a third of the refuse that ends up in landfills, but there are projects looking into better ways of reusing and recycling materials.Spencer Colby/The Globe and Mail

In the past two decades, Canada has taken significant strides forward in creating greener, more sustainable buildings. Notable recent examples range from Manulife’s carbon-neutral 980 Howe St. office tower in Vancouver to EllisDon’s award-winning green retrofit of Toronto’s iconic Massey Hall.

According to the Canada Green Building Council (CAGBC), there have been some 5,145 projects across the country certified by LEED (Leadership in Energy and Environmental Design), the international rating system for ecofriendly buildings, since 2003. Of those, 362 are ranked platinum – the highest LEED status. On top of that, some 57 projects have attained the CAGBC’s Zero Carbon Building standards, launched in 2017 to encourage carbon-free design and performance.

For all that, Canada could be doing a lot better.

“We’re way behind other G20 countries,” says lawyer Catherine Willson, who is chair of the Toronto Construction Association’s Environmental Committee. “We’re performing poorly on a bunch of fronts. We should be, and I hope we are, in catch-up mode.”

Ms. Willson says most of the construction industry wants to build sustainably, but for building owners, cost remains a barrier. She believes a carrot-stick combination of better incentives and stricter legislation could get more owners to think green.

Energy-efficiency requirements are already tightening up, from changes in the national building codes to the establishment of provincial and municipal standards, such as the BC Energy Step Code and the Toronto Green Standard. Both Vancouver and Toronto have set net-zero greenhouse gas emissions targets for all new buildings by 2030, while Montreal’s must be net zero by 2025.

“Climate change is on everyone’s agenda right now,” says Michael Singleton, executive director of Sustainable Buildings Canada (SBC). There’s a lot of pressure to reduce emissions to meet the government goals, he says. “I wouldn’t say the industry has figured out how to do it exactly, but nonetheless that expectation has been created.”

Mr. Singleton says it’s led to a sea change in the way new buildings are constructed. “We’ve seen it play out in the window-to-wall ratio. The most energy-efficient window will never be as efficient as a wall, so we’re seeing smaller windows.”

There is also a move to more sustainable materials, such as mass timber, which both sequesters carbon – keeping it out of the atmosphere – and uses less energy to manufacture than concrete and steel. The trend is already unfolding on Toronto’s waterfront, with the mass-timber construction of George Brown College’s Limberlost Place and the T3 Bayside office-and-retail development.

There are also continuing efforts to find a greener way of producing concrete, the principal material used in most construction. They include a new technology by Halifax-based CarbonCure Technologies that injects recycled CO2 into the concrete mix.

The type of energy used to run buildings likewise needs to change, Mr. Singleton says, especially with existing structures. “Those are the vast majority of buildings; how we retrofit them can go a long way to achieve our emissions goals.”

In place of fossil fuels, he expects alternative systems such as air-source heat pumps will become ubiquitous. Other options are advanced technologies such as variable refrigerant flow (VRF), which, while costly, are much more energy efficient.

At the SBC’s recent annual Green Building Festival, Canadian builders got a glimpse of some exciting international initiatives to meet zero-carbon goals. They included a successful project by the waterworks agency in Oslo to significantly reduce emissions on the job site by switching to electric-powered heavy equipment, from excavators to trucks. The Norwegian capital is now on track to have zero-emissions construction in city projects by 2025.

“Europe is ahead of the curve in comparison with North America, due partly to the resource scarcity there,” Mr. Singleton says.

“There’s no reason we can’t borrow from their example,” Ms. Willson says. “It’s clearly working there.”

Construction waste is also a huge issue – in Canada, it accounts for close to a third of the refuse that ends up in landfills. The problem is currently being tackled in research by Montreal’s École de technologie supérieure (ÉTS) at the University of Quebec. As part of its drive to help transition Quebec from a linear to a sustainable circular economy, ÉTS is running a lab in partnership with the construction sector to find better ways of reusing and recycling materials.

“We have two pilot projects to see if we can deconstruct buildings instead of demolish them,” says Annie Levasseur, a professor in ÉTS’s construction engineering department and scientific director of the school’s Centre for Intersectoral Studies and Research on the Circular Economy (CERIEC). So far, the results have been promising. Used windows and doors were salvaged, repaired and resold, at a profit that offset the cost of the deconstruction.

“Now the challenge is whether we can implement this [practice] more generally,” Dr. Levasseur says.

Ms. Willson is encouraged by the fact that, as opposed to 20 years ago, sustainability is now an essential aspect of construction.

“Everybody recognizes how important it is,” she says, and, as a consequence, “the buildings that are going up are better. We’re making a lot of progress – we just need to get there faster.”

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