Firefighters were dispatched to a home on the unit block of Richards Lane shortly after 11:00 a.m.
Heavy flames were reported upon arrival.
At least five fire departments were called to the scene - approximately 60 firefighters in all.
A firefighter from Aetna Hose Hook and Ladder Company was injured when he fell through part of the first floor into the basement.
Fellow crew members used a ladder to pull him to safety. He was later taken to Christiana Hospital where he was treated and released.
It took fire crews less than an hour to combat the flames.
The home sustained heavy structural damage. No one was home at the time but officials say the family's dog died in the blaze.
The cause of the fire remains under investigation.
