A three-alarm fire broke out Thursday night at a Connecticut Ave. three story residence.

Firefighters from Boston and Cambridge joined the Somerville Fire Department in extinguishing the blaze.

While no injuries were reported, the fire displaced 7 residents and the home was boarded up on Friday. Damage to the building was estimated to be about $250,000.

Preliminary reports indicate that the fire started in the back on the third floor and quickly spread throughout the building and onto the roof.

The State Fire Marshal’s office is reportedly in charge of investigating the cause of the fire.