Concern about the structural integrity of the more than 60-year-old building came to a head last year, when residents evacuated it amid fears it could collapse.
Trouble began when a construction crew discovered longstanding but until then unknown problems with the concrete used to build it, the Globe has reported. Residents left, hoping they could reinforce the building and someday return. But further analysis found it to be beyond saving, and they opted instead to tear it down, then sell the land underneath it.
Another evacuation is in the future.
Before the demolition, residents of a 16-unit condo building next door, at 205 Mount Auburn Street, will need to leave their homes in mid-November for several weeks, officials said this week. The demolition team will set up a perimeter around the building that the public is not allowed to enter, which during the early stages of work at the site will overlap with that building.
The city will pay for those residents’ temporary housing, and will seek to be reimbursed for it — and all other costs associated with the demolition — by the current owners of the doomed Riverview building.
City leadership have said for months now that they are being intentionally over-cautious, given the risk of catastrophe if the building were to collapse and endanger neighbors, pedestrians, or passing cars.
“I hope everyone says to me that closing Mount Auburn Street was melodramatic, and asking these people [who live next to the demolition site] to evacuate was unnecessary,” Watkins said at the Wednesday meeting. ”That would be a good outcome.”
Other neighbors on nearby Sparks Street will be able to stay in their homes, but three will temporarily not be able to access their driveways.
City government, with support from the building’s condo board, took over the management of a situation City Manager Yi-An Huang in July called “tragic and unprecedented.”
Officials set aside $20 million in public funds for it, a figure they said they believed would be enough to account for contingencies with the complex task ahead.
As part of the arrangement, the city will seek to be made whole once the work is complete, possibly during a sale of the land.
When work begins, it will be more CLANK-CLANK-CLANK than KABOOM. A demolition crew will remove the floors one-by-one using a 145-foot-tall excavator and other equipment, including misting devices that cut down on dust. Demolition will not involve the use of explosives, officials said. And the construction crew does not plan to demolish the building’s foundation.
The firm overseeing the demolition, called NorthStar, has experience with similar buildings, officials said. This year, it took down a 17-floor concrete building in Stamford, Connecticut.
Asbestos inside the building can’t be removed, so its concrete will need to be treated as hazardous material, and will have to be trucked to a landfill in Ohio. Contractors will also need to take steps to monitor air quality and the impact of sound and vibration on neighbors.
In the meantime, the city has taken extraordinary safety precautions in this corner of the city, a short walk from Harvard Square and just across Mount Auburn Street and Memorial Drive from the Charles River, that have left nearby streets closed, and a large chunk of a residential section of Cambridge blocked off and guarded by a police detail.
The city expects to begin reopening streets as demolition progresses and floors of the building are removed, but officials have not yet released a timetable for which ones will be re-opened, and when.
Spencer Buell can be reached at spencer.buell@globe.com. Follow him @SpencerBuell.
