Overshadowed by neighboring Union Station and the nearby U.S. Capitol, the seven-story largely precast-clad structure at 20 Massachusetts Ave. NW in Washington, D.C., likely has been perceived as just another office building occupied by a government agency. And indeed it was for most of its 50-year life. That perception will soon change with the scheduled spring 2023 completion of the building’s $200-million transformation into 20 Mass, a 425,433-sq-ft mixed-use development that will combine Class A office space with a 274-key Royal Sonesta Hotel and ground-floor retail.
The building will be expanded by more than 101,000 sq ft by the addition of three floors and a full-height eastward expansion, and clad with a new unitized curtain wall exterior. It will feature amenities such as a 15,508-sq-ft penthouse level with a green roof, a fully equipped fitness club with private lockers, a secured bike room and restaurants. According to architect Leo A Daly, a streetscape redesign will transform the building’s visual and experiential relationship to the Massachusetts Avenue corridor and surrounding streets.