The Cary Fire Department said the fire broke out at 3:30 p.m. in the 100 block of Acadia Court.
"The heaviest fire was on the backside of the house," said Barry Jones, battalion chief for Cary FD.
There was no one else inside the house at the time.
The fire also melted part of the siding off of the home next door.
"I went down to unload the dishwasher in our sunroom," Rob Johnson, who lives next door, said. "I looked up and there was a fire burning next door about four feet high and I said, 'No, this is not right!'"
Johnson managed to find his phone and call 9-1-1. He said he's thankful no people were injured.
"It's kind of scary," he said. "It got very warm inside--my windows were warm."
Johnson has lived on Acadia Court for more than 20 years.
"Everybody gets along well," he said. "We've seen little kids grow up and we've seen those kids having grandkids. Everybody knows everybody--it's a nice neighborhood."
In addition to the Cary Fire Department, Cary EMS and the Cary Police Department responded to the scene.