It took firefighters 12 hours to get a fierce blaze in a vacant three-storey building on north Main Street — which is sometimes used by homeless people — under control Tuesday.

It took firefighters 12 hours to get a fierce blaze in a vacant three-storey building on north Main Street — which is sometimes used by homeless people — under control Tuesday.

Firefighters arrived at the Beveridge Block at 802 Main St. at about 12:30 a.m. and fought the flames from the outside using aerial ladders, since it was unsafe to enter the structure.

A drone detected hot spots from above while the police helicopter provided information to incident commanders.

The brick-and-stone building, built in 1907, was uninhabited, the city said in a release.

The building is expected to be a total loss and the cause is under investigation, the city said.

A neighbouring apartment block was evacuated as a precaution. Residents were given shelter on a city bus and the Salvation Army provided food and drinks. A social services team was sent to help them find alternative shelter until their building is deemed safe.

One bystander told the Free Press the Beveridge Building is "not a good building, let’s just put it that way." The man, who works close by and didn't want his name published, said "the fire probably did it a favour."

He said the building was a common space for transient people to take shelter.

Police closed Main Street’s northbound and southbound lanes between Higgins and Dufferin avenues, but reopened the northbound lanes at about 7 a.m.

Southbound lanes remained closed and traffic was being redirected west onto Selkirk Avenue.