The transformation of the former Cadillac Motor Car Co. Assembly Plant in Detroit into a 90-unit apartment building preserved a historic property while also creating new housing in the neighborhood.
The project received a 2026 CoStar Impact Award for redevelopment of the year for Detroit, as judged by real estate professionals familiar with the market.
Located at 450 Amsterdam St. in Detroit, the Amsterdam Lofts offer 90 new apartment units with studio, one-bedroom and two-bedroom floor plans. The property includes 20% affordable housing at 80% of the area median income alongside market-rate units. The property has secured parking, indoor bike storage, a community room, a pet washing station, outdoor amenity spaces with a kitchenette and grills, in-unit washers and dryers and individual climate control.
The property sits in the New Amsterdam Historic District, listed on the National Register of Historic Places since 2001. More specifically, it’s located in Detroit’s TechTown neighborhood, a premier technology incubator, and near Wayne State University and the Detroit Pistons’ headquarters.
The building was constructed in 1905 as the Cadillac Motor Car Co. Assembly Plant, designed by architect George Mason, who also designed the Detroit Masonic Temple and the Grand Hotel on Mackinac Island. It was one of the original Cadillac automotive plants in Motor City.
About the project: Detroit-based Jonna Construction, a full-service construction management and general contracting firm, was the general contractor for the project. Real estate private equity investment manager and development firm Greatwater Opportunity Capital was the developer and investor in the Amsterdam Lofts.
The redevelopment work preserved Mason’s pioneering reinforced concrete structure, which was designed to protect against fire after the destruction of Cadillac’s previous buildings. At the same time, it transformed the former assembly plant into modern loft-style residences while keeping its industrial character.
Michigan's State Historic Preservation Office has recognized the restoration work, and the Albert Kahn Legacy Foundation commemorated the building’s legacy during a ribbon-cutting ceremony.
JPMorgan provided Federal Historic Tax Credit equity for the project, and its Corporate Social Responsibility team has highlighted Amsterdam Lofts as a best-in-class example of how historic preservation can drive neighborhood revitalization while honoring the past.
What the judges said: “Amsterdam Lofts is impactful because it saves an irreplaceable piece of Detroit’s automotive heritage and reinvents it as much-needed housing. Its blend of historic preservation and community-focused redevelopment brings new life, economic diversity and long-term vibrancy to the TechTown district,” said Katie Rizzo, senior research analyst at Colliers.
They made it happen: Justin Golden, co-founder of Greatwater Opportunity Capital; Matt Temkin, co-founder of Greatwater Opportunity Capital; Raphaela Korotky, leasing consultant at Detroit Living; Katrina Stevenson, property manager at Detroit Living; Jordan Mancos, assistant property manager at Detroit Living; Eric Brown, service manager at Detroit Living; Thea Robbert, asset manager at Greatwater Opportunity Capital; Andi Mcintosh, director at Greatwater Opportunity Capital; Reid Mauti, associate at McIntosh Poris Architects; Joseph Jonna, CEO of Jonna Construction; Kristine Kidorf, owner of Kidorf Preservation Consulting; Tim Karp, head of historic tax credit equity at JPMorgan Chase & Co.; Mara Lancaster, architect for the Michigan State Historic Preservation Office; and Daniel Cousino, founder and partner at Cousino Law.