The fire was reported shortly after 10 a.m.
Firefighters from the Cheswold Fire Company arrived at the scene to find flames shooting from the first and second floors, Assistant State Fire Marshal Michael Chionchio said.
There were no reported injuries, as smoke alarms woke up two second-floor residents who were sleeping at the time, and they escaped unharmed, Chionchio said.
Heavy fire damage is estimated at $200,000, he said.
The Red Cross is assisting six adults with emergency supplies and housing.
