City firefighters confined damage to two upstairs rooms at 251 Fairmount Ave. late Sunday.
Fire Captain James Shanahan said crews were called just before 11 p.m. and were at the scene about four hours.
"When company five first arrived, they had fire coming out the windows of the second-floor of the bedroom at the rear of the house," Shanahan said. "Fire was lapping up the siding to the eaves of the roof peak in that area."
The cause is under investigation.