Montalba Architects has created an artful city sanctuary by modernizing a 1920s landmarked penthouse on New York’s Upper West Side. The firm maintained the building’s historic vernacular while renovating a wrap-around terrace, incorporating a marble fireplace, eat-in kitchen and dining room, private gym, and two bedrooms with ensuite baths. The addition of clean, modern millwork and fixtures further accentuates the original coffered ceiling, molding and casing details.