The fire was reported at 2:09 a.m. at a single-family house at the intersection of South 17th and East San Antonio streets near Coyote Creek, according to San Jose fire Capt. Barry Ehlers.
Two residents were asleep inside the home when they awoke to a smoke alarm sounding. Both residents were able to safely flee the structure prior to firefighters arriving at the scene, Ehlers said.
No injuries were reported but the fire displaced the residents and caused extensive damage to the house, according to Ehlers.
Built in 1907, the home was constructed largely of wood and plaster, Ehlers said, causing firefighters to experience significant difficulty while battling the blaze.
The fire spread rapidly to the home's wood interior and attic spaces. The walls of the home were made from an old-style drywall constructed from wood and plaster that had to be torn apart piece by piece to reach hotspots, according to Ehlers.
The blaze was knocked down at about 4:30 a.m., but crews remain at the home this morning searching for potential hotspots.
A neighboring home also sustained minor damage when a section of the roof caught fire, Ehlers said.
The cause of the fire remains under investigation this morning.