Recycling Office Towers

Having lived in Toronto for more than a decade and worked there for close to 40 years, I'm used to the construction in North America's fastest-growing major city.  According to a CBC radio report I heard the other day, there are more than 250 construction cranes poking up from the city's skyline.

That construction often involves destruction, because older buildings have to be torn down. As the city gets denser, often that's more than just knocking down an old strip mall or small commercial building. Sometimes it means taking down, or at least gutting, a multi-storey office tower. (I've worked in two 10-storey buildings that were eventually stripped down to the structural steel and rebuilt). 

What happens to all that material? In past years, much of it would end up in landfill sites, or in Toronto's case, get dumped off the Leslie Street spit to create new land. But environmental concerns are forcing developers to consider recycling the material from old buildings. The New York Times has a fascinating article* on how buildings are being recycled and new buildings designed so their eventual demolition will be more environmentally friendly. 

In recent years, concern about waste and the climate has led cities like Portland, Ore., and Milwaukee to pass ordinances requiring certain houses to be deconstructed rather than demolished. Private companies in Japan have spearheaded new ways of taking high-rises down from the inside, floor by floor. China promised to repurpose 60 percent of construction waste in its recent five-year plan. But perhaps no country has committed itself as deeply to circular policies as the Netherlands. In 2016, the national government announced that it would have a waste-free economy by 2050. At the same time, the country held the rotating Council of the European Union presidency, and it made circularity one of the main concepts driving the industrial sector across the bloc. Amsterdam’s city government has set its own goals, announcing plans to start building a fifth of new housing with wood or bio-based material by 2025 and halve the use of raw materials by 2030. Cities like Brussels, Copenhagen and Barcelona, Spain, have followed suit.

Even in the Netherlands, though, creating a truly circular economy is challenging. Nearly half of all waste in the country comes from construction and demolition, according to national statistics, and a stunning 97 percent of that waste was classified as “recovered” in 2018. But most of the recovered waste is downcycled — that is, crushed into roads or incinerated to produce energy. A 2020 report by the European Environment Agency pointed out that only 3 to 4 percent of material in new Dutch construction was reused in its original form, which means that trees are still being cut for lumber and limestone still mined for cement.

* I've gifted the article from my subscription so it should be in front of the paywall.