Investigators are looking into the cause of the fire, but the current suspect is a spark from the brick chimney that landed on and ignited the shake roof, Mr. Romero said. A fire had been going in the fireplace, he added.
No one was injured and the fire did not represent a threat to the dry and wooded area traversed by Lawler Ranch Road, Mr. Romero said.
"The way we had it contained, there was never any danger," he said, noting that the home had a good buffer zone — a perimeter intentionally cleared of flammable material.
About 20 firefighters came to the scene and the equipment included a water supply truck since the area has no hydrants, the battalion chief said.
A caretaker reported the fire, which did about $50,000 damage to the roof and interior, the battalion chief said.