When the Owners, a NY religious not-for-profit organization, bought this 5-story 15,000 sf townhouse in Manhattan’s Upper West Side, they inherited its layout and systems and kept them unchanged, because they did not want to alter the interiors, which they had fallen in love with. The Owners used the house as a single-family residence and our challenge was to keep the single-family use and feel of the house while making it more functional. The client asked us to synthesize all their requirements in a way that, not only made sense of the building, but also looked integrated, as if nothing had changed. The upper floors were comprehensively reorganized with a total of 12 bedrooms, each with its own bathroom. A six-stop residential elevator was added, and all the electrical, mechanical and plumbing systems were upgraded. The “historical rooms” were “spruced up” and the exterior brick and stone was cleaned or repaired, as needed. Originally designed as a single‐family townhouse and built in 1901, the building is eligible to the National Register of Historic Buildings as a contributing building to the Riverside – West 105th Street Historic District.