Demolishing buildings is a waste. There's another way: deconstruction
Emily Chung | CBC News | Posted: November 17, 2024 9:00 AM | Last Updated: November 28
Taking apart and separating valuable materials allows them to be recycled, reused
When Meredith Moore moved from New York to Toronto, she was astonished by the amount of home renovation happening in the city — and by the full construction waste bins.
"I would see these dumpsters just filled with wood and trim and doors and all these things that I knew were not waste," said Moore, who has always looked for ways things could be reused in her previous work as an interior designer.
So when her family bought their own Toronto fixer-upper four years ago, she told their contractors that they wanted to save as much material as possible.
"And we were just met with, 'Nos,'" she recalled. "That's not how it works. All that material is junk. No one is ever going to use it.'"
But Moore didn't want to take no for an answer. Instead, she founded Ouroboros Deconstruction, putting together a crew tasked not with demolition, but "deconstruction," so the materials could be reused and recycled.
Deconstruction may seem slow, inefficient and potentially costly compared to just knocking something down. But there's growing interest from building owners and the construction industry alike in taking a more careful approach, which cuts waste and emissions by giving new life to old materials.
The problem with demolishing buildings
If you want to renovate or replace an existing building, standard practice has been demolition — breaking it apart with tools and machines, and putting the resulting rubble of mixed wood, drywall, insulation and whatever else in a bin destined for the dump.
That results in a lot of waste — four million tonnes annually nationwide, according to a Statistics Canada estimate. About 30 per cent of the material piled up in a typical landfill is from construction, renovation and demolition (CRD). The largest fraction of that is typically wood, which decomposes into the potent greenhouse gas methane.
Demolitions happen thousands of times a year in cities like Vancouver, which is racing to replace single family houses with multiplexes that provide more homes in the same amount of space amid housing shortages.
Many construction materials can be reused and recycled — but they rarely are. That's partly because the demolition process breaks up and mixes materials into a rubble that's hard to separate into recyclable components.
Buildings and construction account for up to 37 per cent of emissions worldwide, the UN reports. About 30 per cent of those of those carbon emissions — called embodied carbon — come from the energy used in the production of the materials that go into the building. Replacing one building with another generates an entire building's worth of emissions, which means that, from a climate perspective, it's better to extend the lifetime of those materials and reuse them than discard them.
Other options: Deconstruction and repurposing
Light House is a Vancouver-based think-tank focused on "circular" construction through recycling and reuse. In a 2023 report, it estimates that about 20 per cent of demolished homes could have been moved to new locations.
WATCH | Homes set for demolition moved to where they're needed:
Another 60 per cent could have been deconstructed, and the materials salvaged for reuse and recycling.
Moore describes deconstruction as "construction in reverse."
"We're starting from the interior. We're removing all the finishes. We're salvaging doors, flooring, fixtures, appliances, and then we move on to the structure.... We're salvaging all that lumber, we're recycling asphalt shingle — everything else we can," she said.
The concrete or stone foundation can be either recycled or reused in the new build. She said more than 90 per cent of the materials can be reclaimed or recycled, and kept out of the landfill.
Her company's latest project was a water-damaged, derelict bungalow on the west side of Toronto. Homeowners Emma and Chris Arthur thought they would have to demolish it but had guilty memories from a previous reno.
"Everything ended up in the bins [headed to the dump]," Emma Arthur recalled. "That was really devastating."
This time, they vowed to do things differently. They hired a sustainability consultant who brought up deconstruction — and they went for it.
Now Moore's crew is taking down the wood frame piece by piece with crowbars and other handtools, then sorting the materials. Arthur said it was interesting to hear how everything would be reused. The wood beams, for example, are being turned into stools that will be upholstered with luxury fabric off-cuts.
Isn't this slow, expensive and labour intensive?
Erick Serpas Ventura, CEO of Vema Deconstruction in Vancouver, acknowledges that traditional demolition using machinery such as excavators is shockingly fast — often, less than a day.
Deconstructing a wood frame house, on the other hand, takes a little under a week with four to six people and some machinery. Ventura said, "You have more people doing more labour, but you're also creating more jobs."
Moore said deconstructing a brick home, like those found in Toronto, can take longer and cost more — 50 to 100 per cent more than the cost of demolition.
Local government incentives and bylaws, as well as sales of valuable recovered materials, could make the cost of deconstruction more competitive.
In a recent pilot project, the waste management network in Quebec's Gaspesie Region deconstructed an industrial building in Chandler and four in Grande-Riviere, and found the cost slightly lower than the cost of demolition. The project dumped only 77 of 408 tonnes of material, saving tens of thousands in tipping fees and transportation costs. About 60 per cent was sold to local construction projects, including a school renovation, for reuse.
Reusing materials can be challenging
Everyone interviewed for this article hopes to see more reuse.
Serpas Ventura says century homes in Toronto and Vancouver are built with huge beams from old growth forests that no longer exist.
"We're actually getting a lot of excitement from designers, architects, the engineers that are learning to work with us to put this material back [into buildings.]"
That's more challenging than it sounds. Melania Grozdanoska is co-founder and co-director of Surcy, a Montreal-based consulting firm that helps local architecture and construction firms navigate deconstruction and reuse. She said building codes and standards expect people to use new materials.
With reuse, "You have to do a lot of extra research to find materials, but then also to figure out if you can use them and how you can use them in order to be able to respect the standards and the codes."
Surcy recently helped renovate a former Montreal antique store into an assistance centre for homeless Indigenous people, reusing materials from the old building.
Denise Philippe, senior policy adviser with the National Zero Waste Council, said changes to building codes and recertification of used building materials are needed to make reuse more accessible. She added, "We need to have a market and space to store materials that can be reused over time."
That's something that circular construction think-tank Light House is working on. It recently launched a "matchmaking service" for users of and generators of "waste" construction materials on Vancouver Island called the Building Materials Exchange (BMEx).
Gil Yaron, the group's managing director of circular innovation, said it is also working with non-profit Habitat for Humanity to create a physical store for large quantities of used building materials such as bricks. The organization already has similar shops, called ReStores, that sell things like furniture, cabinetry and plumbing fixtures.
Philippe said government policies and building procurement can also encourage deconstruction, recycling and reuse.
Despite the challenges, many of those interviewed think there is growing interest in deconstruction — from building owners like Emma Arthur to architects, designers, governments and those in the construction industry.
Grozdanoska said, "What is promising is that I think there is an interest from the people on the ground to change. People want to do it. They just need the support."
Corrections:- An earlier version of this story incorrectly said Meredith Moore moved from Toronto to New York. In fact, she moved from New York to Toronto. November 17, 2024 4:26 PM