Massachusetts-based developer Benchmark Senior Living plans its first project under its newly formed urban-focused division in Philadelphia at the current site of a parking garage at 12th and Sansom Streets.

Benchmark Wellness Management, as the six-month-old unit has been named, is teaming with developer Brickstone Cos. to build a 24-story tower for residents 62 and older at the Brickstone-owned site, Benchmark said in a news release Tuesday.

It had not yet been decided whether the units will be condo or rental, a Benchmark spokesperson said.

Other developers have acknowledged having retirees and near-retirees in mind for their Center City projects. Carl Dranoff, for example, has said he expects a “silver tsunami” of downsizing empty nesters at his recently announced Arthaus tower on South Broad Street.

Watermark Retirement Communities has long operated a tower with 464 rental apartments and assisted-living units in the city’s Logan Square section. But Benchmark’s project appears to be the first explicitly age-restricted residential tower set to rise as part of Center City’s current wave of building.

“We handpicked Philadelphia for our first development because its Center City revitalization has not only captured our attention, but also the interest of local and suburban boomers,” Denise McQuaide, president and chief operations officer of Benchmark Wellness Management, said in the release.

The Park America garage that the project will replace was acquired by Philadelphia-based Brickstone for $14.5 million in late 2015 from the estate of Samuel Rappaport. The developer had previously said it planned a pair of towers at the site with residential units, along with offices, a hotel or retail, or some combination of those.

The project now planned will have 220 units from 800 to 1,400 square feet, Benchmark said. Amenities at the building, scheduled for completion in 2023, are to include a spa with massage services, a heated pool, and “Center City’s first and only pickleball court,” it said.

Benchmark Wellness Management’s Waltham, Mass.-based parent operates 63 senior living communities with independent and assisted-living units, memory care, and rehabilitation and nursing services, primarily in New England, according to news releases and the company’s website.

Its sole Pennsylvania property is the Wellington at Hershey’s Mill facility in West Chester.

The planned tower will “bring a lifestyle of transformative wellness to Philadelphia’s active, discerning and sophisticated 62-plus population,” McQuaide said in the release. “Those individuals ... want to live in exciting, cultural, urban locations.”

News of the project was first reported by PlanPhilly.