After Just 8 Years, SoMa's 58-Story Millennium Tower Is Sinking, Tilting

After Just 8 Years, SoMa's 58-Story Millennium Tower Is Sinking, TiltingPhoto: Ethan T./Flickr
Allie Pape
Published on August 01, 2016

In a distressing prospect for both residents and taxpayers, the Chronicle reports today that SoMa's 58-story Millennium Tower—completed only eight years ago, in 2008—is showing signs of both sinking into the ground and tilting. 

An independent consultant hired to monitor the high-rise at 301 Mission St. found that it's sunk 16 inches into the ground since its debut. The sinking has occurred unevenly, leaving the tower also tilting two inches to the northwest.

While a Stanford engineer interviewed by the Chron said that the sinking likely doesn't pose any safety risks, it could cause cracking walls, malfunctioning elevators, and other annoyances for residents—a major issue in a building that celebrities like Hunter Pence and Joe Montana call home, and where condos run from $1.6 million to as much as $10 million.

A representative for the Millennium Tower's owners says that construction on the forthcoming Transbay Transit Center is to blame for the sinking and tilting. The Transbay Joint Powers Authority (run by the city of SF, AC Transit, Caltrans and the agency behind Caltrain) spent $58 million on an underground buttressing system to shore up the Millennium before beginning nearby excavation in 2010, but the authority's contract could leave taxpayers on the hook for any damage caused to the building by construction.

The authority has denied responsibility for the Millennium Tower's issues, arguing that the building is sinking because it's framed in concrete instead of steel and wasn't anchored to bedrock, in order to cut costs. However, a Millennium representative says that numerous other downtown skyscrapers, including the St. Regis and Intercontinental hotels, were constructed in the same manner. 

The Millennium's homeowner association has retained engineering consultants and is "evaluating [its] legal options," it told the Chron. Potential solutions include pumping cement underneath the building's base and drilling new piles, but both undertakings would be expensive and lengthy.