An early morning fire caused extensive damage to a Prospect Street home Wednesday but no injuries to a family of seven, according to Deputy Chief Joseph Callaghan of the Maplewood Fire Department.

The fire began at around 12:30 a.m. as the family slept: a couple and their four young children on the second floor and the children's grandmother, who was visiting, on the third floor.

"The family was alerted by smoke detectors on the first, second and third floors," said Callaghan. "The wife called 911 while the (husband) made sure (his) mother was OK and evacuating. The children and rest of the family then exited the home."

As the fire department arrived, the fire was extending to the second floor exterior, Callaghan said. Maplewood's Platoon 2 was assisted by the South Orange and Millburn Fire Departments in extinguishing the fire.

The back exterior of the house suffered extensive damage, Callaghan said, but the house is habitable.

Deputy Chief Walter Nugent said several factors were critical in saving the family: properly placed smoke detectors; the fact that the family promptly called 911, and that the family had a pre-planned evacuation plan in place.

"If the family didn't have smoke detectors, it could have been very bad," said Callaghan.