Former Morgan Stanley CEO John Mack paid $13.5 million for a Manhattan carriage house in 2009; after renovating the 16,000-sq-ft Upper East Side mansion, it is now listed for $80 million

Former Morgan Stanley CEO John Mack and his wife, Christy, have listed their palatial home at 165 East 70th Street, according to a report by The Wall Street Journal. The historic neo-Italian Renaissance carriage house, built in 1910 and later transformed into a spectacular residence by the couple, is asking $80 million. If it fetches the asking price, it would become the priciest residential townhouse ever sold in New York City. The Macks purchased the 15,978-square-foot residence in 2009 for $13.5 million and transformed it into a 20-room home by 2011.A carriage house built in 1910In 1902, banker Henri Wertheim hired architect C.P.H. Gilbert to design the building. Like many carriage houses on the block, this one was intended to house horses and the staff who cared for them. Wealthy families on the Upper East Side wanted stables nearby, but not so close that the smell reached their front doors.By 1920, the building had become a garage and chauffeur’s quarters for Singer heir Stephen C. Clark, according to the listing. Decades later, Paul and Bunny Mellon used it as a private garage. The structure is a “landmarked limestone Neo-Italian Renaissance carriage house, built exceptionally wide (33 by 100 feet)”, according to the listing. It was unusually broad for a Manhattan townhouse.The Macks bought the property in 2009The Macks bought the building from Bunny Mellon in 2009 for $13.5 million. The couple had raised their children in Westchester County and spent roughly a decade looking for a move-in-ready townhouse in Manhattan. When that search failed, they decided to build one.“It was a distressed property. It was always used as a garage,” listing agent Mike Fabbri of The Agency told the New York Post.Six years of renovationThough the Macks had hoped to find a turnkey property, they decided to give the carriage house an extensive makeover. The renovation took about six years, according to The Wall Street Journal. Christy Mack led the design. The couple kept the limestone façade but added a floor and reinforced the structure with steel. The architecture firm Sawyer Berson and interior designer Eleanor LaSota worked on the project. “It still had the horse ramps and stalls, like a barn,” Christy told the newspaper. The ramps and stalls were gone by the time the work was finished, replaced by a home with 20 rooms.What the buyer getsThe home spans 15,978 square feet across six floors and has six and a half bathrooms. It features “quarter-sawn hand-pillowed oak floors, custom Holland & Sherry wallpapers, Sahco drapery, Brunschwig & Fils fabrics, and Armani, Ralph Pucci, and Allison Berger lighting”, according to the listing. A wrought-iron and limestone staircase climbs to a skylight, and an elevator serves every floor. Heated flooring runs throughout the house, including the terraces and the pavement outside. The property also has a bulletproof front door.The house has a 13-seat soundproof theatre and a wellness area with a cold plunge, steam room, sauna and gym. The garage is on the lower level and can double as an entertaining space. The house also has a wine cellar with room for more than 6,300 bottles. A 480-square-foot rooftop terrace offers unobstructed views of the city.There is also a library with a fireplace. A playroom and study are pre-plumbed to allow conversion into a space mirroring the primary guest suite.Meanwhile, the record for the most expensive townhouse sale is held by a mansion at 14 East 67th Street, which sold for $77.1 million in 2019. If the Macks get their asking price, the sale would break that record.Ready to Make a Smarter Property Decision? Build Your Legacy with TOI Homes.