21 Dupont Circle is an 81,000-square-foot base building and interior office to conferencing conversion project for this Transit Union Headquarters, addressing complex jurisdictional challenges while realizing the client’s vision. The project required coordination with dual historic districts, Advisory Neighborhood Commissions, the Historic Preservation Review Board, DC Preservation League, Landmarks Commission, DC Office of Planning, and the DC Zoning Board of Adjustment. Core and shell upgrades include a new glass façade, redesigned entry, enclosed courtyard, indoor/outdoor third floor, faceted skylight, full mechanical and electrical system replacements, upgraded restrooms, and structural modifications such as fiber-reinforced roofing to support an occupied roof terrace. Additional enhancements feature an elevator extension, new roof deck, stair enclosure, and roof canopy. The interior renovation spans three interconnected assembly floors—public, training, and executive lounge—with upper levels dedicated to staff offices, culminating in an executive suite and boardroom on the top floor. All audio-visual systems were designed and integrated in-house.