Firefighters hacked through the roof of a San Bruno residence early Sunday morning as they worked to extinguish a 2-alarm blaze suspected to be an electrical fire, fire officials said.

The fire started around midnight at 110 Linden St., said Millbrae Fire Department Division Chief Ron Lavezzo. The first reports came from an Arco gas station nearby that noticed smoke in the area.

Police knocked on the door of the single-family residence to inform residents that there was smoke coming from the second floor of their house. One resident had been awake watching TV, and smelled smoke, but thought that a neighbor had been using a fireplace, Lavezzo said.

"It was kind of a concealed fire," he said.

In the course of fighting the fire, firefighters had to take about a quarter of the house's roof off. The fire was mostly out by around 12:30 a.m., Lavezzo said, but firefighters remained on the scene for several hours searching for remaining hotspots in the attic.

One woman, the home's owner, was taken to the hospital, but her injuries were not serious, Lavezzo said.

Preliminary investigation suggests that the fire was an electrical fire that started in the attic, Lavezzo said. He said the homeowners had been doing some remodeling in the house, but it is unknown if the fire was related to the interior construction work.

He estimated the fire caused $100,000 in damage to the house.

Five fire engines were called to the scene of the fire, and personnel responded from Daly City, South San Francisco, Burlingame, and Millbrae, which shares a fire department with San Bruno.

Lavezzo said electricity to the house has been shut off to prevent the fire from restarting.