The project is sited atop a historic Manhattan brownstone townhouse.  The built structure acts as an envelope for a new exercise swimming pool and helps integrate swimming as a new program in the client’s daily domestic life. The rooftop addition is designed to provide its occupants with complete visual privacy from neighbors during rooftop swimming, while itself remaining invisible from the street level. Exterior sightlines, interior occupation, daylighting and egress all influenced the overall massing volume, while the concept of an envelope constructed from a single continuous surface determined the material resolution and detailing of the project.