The fire, at 1367 Reservoir Ave., which started at 2:30 a.m. Sunday, was on the outside of the building when crews arrived but threatening to spread inside the home, said Deputy Chief Ron Rolfe said.
Rolfe said the department had taken samples from around the fire debris area to send to the state lab to look for accelerates after crews found evidence that suggests the fire was started on purpose.
"This is a slow process and could take several weeks or longer before we know if the fire was set intentionally," Rofle said.
No injuries were reported to civilians or Fire Department members during the incident.
The working fire required four engines, two ladder trucks, the rescue company, an assistant chief, and safety officer.
The home is listed for sale on Zillow for $120,000.
Click here to follow Daily Voice Fairfield and receive free news updates.