The neo-Georgian Tammany Hall on New York's Union Square has assumed various identities over the course of time. The building will now be converted into a contemporary office space. The unassuming hipped roof of the former headquarters of Tammany Hall has been replaced by a new glass dome, which is a nod to the neo-Georgian architectural style but in contrast to the original masonry structure. Terracotta sun shades provide solar shading and evoke the former slate hipped roof.  

The scope of work includes the design and installation of the dome-shaped glass roof on a steel grid shell structure. The dome is meant to be both evocative and respectful of the building’s past while also bringing architectural spectacle to this rather staid corner of Union Square. The roof is made of 850 isosceles triangular panels encompassing a total surface area of approximately 1,100 sqm (12,000 sq ft). The glass panels are fastened to a steel free-form shell grid.