Seven buildings were rendered uninhabitable when a 75-foot-wide chunk of Telegraph Hill slid down a granite and sandstone slope above Broadway about 3:30 a.m. Among the buildings that city officials declared off-limits was a 45-unit condominium complex at 455 Vallejo St. perched at the edge of the newly formed cliff.
City officials speculated that recent heavy rains had triggered the slide, which did not cause any injuries.
A concrete patio connected to the condo building was in danger of falling Tuesday evening, along with several large rocks nearby, said officials with the city Department of Building Inspection. The building’s structural integrity was unknown, and residents were not allowed to return.
Also red-tagged and declared uninhabitable were three apartment buildings on Montgomery Street on the slide’s east side and three buildings on Broadway, including the Broadway Showgirls Cabaret strip club.
The nightclub’s manager, Ian Cabungcal, said the slide had demolished his office. “If I’d been there at the time, I’d have been dead,” he said. “There is a rock the size of a Volkswagen in the middle of my office.”
Building Inspection officials said the slide had occurred on private land and that the owners of the seven affected properties were responsible for removing the 30-foot pile of rocks and stabilizing the hill.
They told the condominium building’s owners that they needed to hire a contractor to remove the concrete and loose rock that engineers considered to be in imminent danger of collapsing. But by late Tuesday, the owners had failed to reach an agreement on how to deal with the problem.
Police, fire and building officials said the situation could take weeks to resolve. A geologist retained by the city to assess the condition of the rock face could have a report by this morning, they said.
“We have to remove a lot of sections (of rock) that are loose and come up with a long-term solution, and that takes a lot of engineers,” said Carla Johnson, deputy director of the Building Inspection Department.
Contractors who viewed the slide Tuesday said they doubted residents would return soon.
Ryan Nagle of Drill Tech in Antioch, which did work for Caltrans to strengthen a rock wall on Devil’s Slide after storms damaged Highway 1 last year, said the hillside that slid Tuesday will probably need structural support to prevent further collapses. To install such support, workers will need to drill 2-inch-thick rebar steel poles into the rock, a job that easily could take crews working around the clock, seven days a week, up to a month to complete, Nagle said.
“The work is a pain … to do here because a crane parked on Broadway or Montgomery Street needs to go over the top of buildings (facing the street) and suspend guys in a basket to do the drilling,” Nagle said.
After inserting the rebar in a grid about every 5 feet along the rock face, workers would pour a concrete-like substance to seal it, he said.
Taking away the pile of rocks at the base of the slide also will require a crane that will have to be parked on Broadway, Montgomery or Vallejo plus dump trucks to haul away the debris, contractors said.
“We’d need to use slings and netting or steel chokes to lift the boulders out, and we’d have to suspend them over the buildings to do it,” said Thomas Hart, a manager with Sheedy Drayage Co.
In addition to the immediate need to remove the unstable concrete slab from the back of the Vallejo Street property and nearby loose rocks, the entire slide area will need to be contained until work can start, said Michael “Mac” McLaughlin, who works for Granite Excavation and Demolition Inc. of San Francisco.
“There’s fissures in those rocks and loose rock suggesting that more could fall,” McLaughlin said. “They’ll probably net it, cover it in plastic, use some sandbags and put a chain-link fence around it.”
While preparations were under way to fix the damage, residents driven from their homes pondered their next moves.
On Broadway, about two dozen displaced people sat inside a Muni bus that was temporarily parked as a shelter in front of their homes. They sipped coffee and ate chocolate doughnuts from a Red Cross wagon. Others spent the day on cots inside a Red Cross shelter set up in a gym on Mason Street.
“I was watching TV when I heard a boom, boom — twice. Two booms,” said Steve Liu, who has lived for 10 years in a flat at 432 Broadway. “At first I thought it was an earthquake. It was scary. There were rocks everywhere. Big rocks. Forty-pound rocks, a foot across.”
Liu said a retaining net was strung along part of the hillside to catch smaller pieces of debris a few years ago.
“They must have put it there for a reason,” he said.
Mark Loftin and his bulldog, Boss, were asleep in their condo at 455 Vallejo when the slide occurred. A police officer banging on their front door was their first notice that something was wrong.
“The officer said, ‘Get your clothes, get your car, and get out,’ ” Loftin said. “There was a lot of commotion but no panic.”
Loftin, who bought his unit two years ago, said he was satisfied at the time by inspectors’ reports that said the hillside was solid.
“When you move into a place on a cliff, you’re aware of the movies and the horror stories about all the worst things that can happen,” he said. “But I was told this was some of the most solid rock in the city.”
Resident manager Anne White, who owns a condo in the Vallejo Street building, said the homeowners association had the hillside shored up about five years ago after some rocks fell. A geologist who surveyed the area recently suggested that the neighbors on Montgomery and Broadway do further work, she said.
The geologist also said, however, that no reinforcement work could be done until after the rainy season, White said.
Owners of other buildings declared off-limits because of the slide said they had no inkling the hill was dangerous.
Peter Chin owns two of the red-tagged buildings, at 426 and 432 Broadway, which between them have 13 apartments and two restaurants. He bought them in August and said the previous owners had told him the hillside was city property.
“I saw on the other side of the rock formation, they had put nets and stuff like that,” Chin said. “And my understanding was that the city was going to do that on my side.”
Chin said he does not believe his insurance will pay for the repairs to his buildings or the cost of shoring up the hill.
Joe Carouba, who purchased Showgirls just two months ago, also isn’t sure whether he’ll have to pay out of his own pocket.
“I sure hope my insurance covers it, but I honestly don’t know,” he said. “We just closed on the place.”
Chronicle staff writer Wyatt Buchanan contributed to this report. E-mail the writers at rselna@sfchronicle.com, srubenstein@sfchronicle.com and mlagos@sfchronicle.com.
