A fire that spread from the exterior of a Santa Rosa townhouse into its attic caused an estimated $150,000 in damage Sunday morning, the Santa Rosa Fire Department said. Firefighters found no functioning smoke detectors inside the residence. A neighbor called in the fire shortly before 7 a.m. No one was home, and no firefighters were injured, officials said. Crews entered the townhouse and pulled down ceiling sheetrock to reach flames in the attic. The fire was controlled in about 20 minutes. Firefighters also cut holes in the roof to vent smoke and superheated gases, according to the department. The cause of the fire remained under investigation as of Sunday. The department did not provide further details about the residence or its occupants.