The owner of the Motor Mart garage in Park Square will be seeking city permission to add 17 stories of residential units to the structure.
In a letter of intent filed with the BPDA last week, CIM Group says it wants to add roughly 280 apartments and condos atop the existing nine-floor garage - the largest car garage in the world when it opened in 1927, and which once offered helicopter service from its roof.
To integrate the "structural core" of the residential tower, CIM would build have to reduce the number of spaces in the garage from 1,058 to about 600. CIM will also add new commercial space on the ground level.
The company expects to file a more detailed set of plans within 30 days.
Motor Mart letter of intent (59k PDF).