A neighbor said they saw the fire from their home on Graystone Drive just before 3 p.m.
Firefighters arrived to Little Stone Circle and saw smoke showing from the rear of the building.
Deputy Chief Chris Iannuzzi said in a statement that the fire was started by a child playing with a lighter.
A mattress caught fire and an adult dragged it outside where it was extinguished by firefighters.
No one was hurt.