Firefighters responded to a fire at 375 Oceanview Terrace in Stratford on Monday morning and said a ventilation fan is the likely cause.
A resident tried to put the fire out with garden hose before firefighters arrived and a neighbor called 911 at 8:36 a.m., according to the fire marshal.
Firefighters were able to contain the fire to the attic, according to the fire marshal, and there was some minor water damage in the rest of the house.
The house is rented and nine people live there, officials said.
Residents said they will be displaced for a time.