The Ontario Science Centre has closed after an engineering firm found the facility's roof panels are in a "distressed, high risk condition" that could fail if snow accumulates next winter.
Infrastructure Ontario said repairing all the roof panels at the Don Mills Road facility is estimated to cost between $22-40 million and would take two years to complete, though cautioned that these estimates "are incomplete and subject to change."
The report says these panels were made with an outdated material called called reinforced autoclaved aerated concrete, or RAAC, a lightweight form of concrete that was popular in the 1950s, but that hasn't been in use since the 1970s.