Demolishing buildings is a waste. There's another way: deconstruction

When Meredith Moore moved from Toronto to New York, 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.

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.

LightHouse 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.

Another 60 per cent could have been deconstructed, and the materials salvaged for reuse and recycling.

Moore describes deconstruction as "construction in reverse."