Conventional construction logic says that you have to build foundations first, roofs last. Montreal, Canada, home to poutine and twisted logic, disagrees.
A Montreal construction company is building a 10-story condo building in the heart of downtown. That itself is not surprising in a city undergoing rapid gentrification; what is unusual is the construction method.
The first floor and roof were built first, and then the roof is raised, a floor built underneath, and the process repeated. That means that no cranes or scaffolding are needed — normally an expensive process, which also involves disturbing traffic, as anyone who's lived next to a condo project probably knows.
Although it's probably a more expensive system than using cranes, it allowed the construction crew to work in a much smaller lot where there isn't really space. And, of course, it means crews can work all year round, since they have protection from Montreal's famously friendly winters.