Boston firefighters responded to a three decker at 47 Woolson St. around 9:15 p.m. on Thursday for what became a three-alarm fire.
The fire started on a rear porch, then spread to the second and third floors.
At 9:30 p.m., firefighters were ordered off the roof. A few minutes after that, firefighters were ordered out of the building. Firefighters entered adjoining buildings with hoses to keep the fire from spreading.
The Boston Fire Department reports 22 people were displaced.