The initial call was received at about 4 a.m. for the fire on Hanover Street in Prince's Bay.
A male homeowner was able to escape safely. No injuries have been reported.
60 firefighters battled the fire which started in the attic.
"It's a labor-intensive operation because the insulation is hiding a lot of the fire, so it's a lot of manpower right now just opening up and getting water on the fire," said an FDNY Deputy Chief.
Fire officials believe the blaze originated in the home's chimney, and because the chimney was not structurally sound, it ended up spreading to the rest of the house.