We worked with SL Green to design a new penthouse at 100 Church Street that enriches the NYC skyline with three stories of vibrant and versatile office space. The addition of a two-story penthouse design streamlines the original Mid-century building's profile while maximizing daylight by enclosing the new spaces with an elegant slim curtain wall. A significant building code and zoning review was undertaken to determine the massing configuration, rooftop access and utilization of the existing mechanical systems. We created new tenant terraces within the building setbacks and added a roof deck that reinforces the architectural traditions of the Financial District with a copper-wrapped cooling tower inspired by neighboring rooftops. Inside, we integrated existing water towers into the design to create a memorable experience that further highlights the relationships between the original building and the addition.