The blaze was reported at a home at 2379 Atlas Peak Road at around 5:30 p.m., Cal Fire Division Chief Dave Shew said.
The fire spread to vegetation surrounding the house. It burned less than an acre of vegetation before firefighters extinguished that blaze, he said.
Firefighters are still battling the fire within the house. Shew said the "unusual design and construction" of the house has made it very difficult to extinguish.
The house's occupants were not at home when the fire broke out and no injuries have been reported.
