Residents of a two-story building at 16 Picadilly Court that contains four condos realized there was a fire when a driver honked a horn to alert them around 9:15 p.m., San Rafael Fire Chief Christopher Gray said.
The residents attempted to put out the fire from an outdoor patio as it continued to spread, according to Gray.
Fire crews arrived in four minutes and found fire and smoke coming from the building's roof. They attacked the blaze from both outside and inside, where flames were spreading into a common attic space and a vacant unit, Gray said.
Firefighters were able to knock down the blaze in 15 minutes, he said.
No injuries were reported, and no residents were displaced, Battalion Chief Jeff Rowan said.
Gray said the cause of the fire has not yet been determined, but that it may have been caused by a flue failure.
The preliminary damage estimate was $60,000, fire officials said.