Ada Ko of Ogawa Depardon Architects and Ingrid Sletten of X-Act Contracting hosted a construction tour of a 17-foot-wide UWS townhouse they have been working on for the past year and a half.

The project is the restoration of and addition to a Neo-Greco townhouse located in the Central Park Historic District. Originally designed by prolific rowhouse architect M. Grenell and constructed from 1883 to 1884, the building is being transformed into a six-level home for a family of four. The design intent was to create expansive loft-like spaces in a 17-foot-wide structure where the main entry/living/dining/kitchen spaces flow into each other horizontally and vertically, with transparent and translucent glass defining the public zones. At the back of the house is a new three-story glass and steel addition with a double-height space and a double-height, triple-panel window facing the garden. The garden is entered through a walkable glass skylight that lets in natural light to the new space in the cellar. The house is crowned with a new sky-lit penthouse. The challenge, however, to realize the design scheme called for excavating, using a process called drilling and splitting. Excavation through a rock ledge of granite and quartz achieved a 10-foot clearance in the cellar, which was then extended 27 feet into the backyard.