Given that it’s got the highest apartment rental rates in the U.S., it’s no wonder that a self-storage operator in San Francisco wants to add apartment units to its facility, not self-storage units.

The facility’s owner, Blue Stone Investments LLC, is seeking to build a fifth story to house 17 “penthouse” apartments at its City Storage facility. The project would add 16,086 square feet of residential space to the 151,372-square-foot facility. The facility is at 500 Indiana St., on the edge of the Dogpatch, Mission Bay and Potrero Hill neighborhoods.

The average monthly rent for a one-bedroom apartment in San Francisco exceeded $3,200 in May, according to

The residential project would cost an estimated $2 million, according to an application submitted this spring to the City of San Francisco. City planners reviewed the preliminary plan and told the owner it will need to obtain building permits and a zoning variance for the project.

The residential mix would feature seven two-bedroom apartments, five studios, four one-bedroom apartments and one three-bedroom apartment. Parking for cars wouldn’t be available, but 17 spaces for bike parking would be.

Aside from the San Francisco facility, Blue Stone Investments owns a self-storage location in suburban Emeryville.

Alexander Harris