The two-alarm fire started in a bedroom on the third floor of the four-storey building on the 2300-block of McIntosh Avenue Thursday night. It was finally extinguished by 8:30 a.m.
Fire crews said the fire spread quickly because there were no sprinklers in the building, but much of the damage was caused by fire hose water.
Around 30 people were forced from the building, and an elderly couple and a dog had to be rescued by ladder off the balconies. One person was taken to hospital for smoke inhalation.
The residents were taken to a nearby hotel and some have already been told it could be months before they are able to move back in.
A marijuana grow-op was also discovered in a suite on the third floor of the building, but firefighters said they did not think it was linked to the fire. Police are expected to speak to the suite's occupant.