When Windsor first decided on the green demolition policy — a common approach in the GTA that hasn’t happened much — officials were hoping for a recycle rate of 80 to 85 percent, not including hazardous waste. But the actual waste diversion rate ended up at 96.5 percent.
“You can never achieve 100 percent, but this is the next best thing,” said engineer Wadah Al-Yassiri, the city’s lead for the $43-million project that started with construction of a new city hall and ended three weeks ago with demolition completed at the old city hall. He called the diversion rate “truly remarkable.”
“It saves us a lot of money, and it’s good for the environment and good for everyone involved.”
The concrete and brick was crushed on site to create a safe material (inspected for garbage and hazardous materials) to fill the huge cavity that remained from the 70,000-square-foot, four-storey structure. That saved the cost of trucking out the material, buying and trucking in new fill and landfill tipping fees, said Al-Yassiri, estimating the savings at around $500,000.
Crews also sorted all the metals from the building, such as steel beams, copper pipes and wiring and sold them for recycling. Of the 8,301.13 metric tons of non-hazardous waste, only 283 tons — a lot of it drywall — ended up in landfill.
Before actual demolition could start, crews from Budget Demolition had to go through the painstaking process of asbestos removal. Al-Yassiri said when the building was constructed in the 1950s, asbestos was considered an amazing product used as a fire retardant and building material. So when they added more asbestos, they were doing you a big favour. Turns out, the old city hall had a generous builder when it came to asbestos. It was found on steel beams and in ceilings, but also in places they didn’t expect, such as overspraying between ceilings and side walls, in staircases and elevator shafts. They removed about 50 per cent more asbestos than expected — a total of 400 tons — which was trucked to a special landfill.