Renovation of, and an addition to, a 4 story townhouse for a large family, completed in 2007.
This 4 story townhouse on the upper west side was originally a single family home, it had been divided into several apartments as so many townhouses in New York were during the depression.
When my clients bought the house it had been partially renovated into an owners triplex on the garden floor, parlor floor and second floor with two rental apartments on the third floor, one of which was a duplex with the bedroom suite on the 4th floor with direct access to the roof. 
After living in the house for a few years my clients wanted to expand keeping only the garden floor as a separate apartment.
They wanted a large kitchen and a direct access from the parlor floor to the garden, and to use the roof of the extension and the roof of the main house as terraces.
The townhouse has a narrow two story extension at the rear yard, opened up and added to, the full width of the lot up to the 30’ rear yard, this space became the new kitchen with a narrow balcony and stair to the garden, a new interior access was created to the garden level connecting to the existing cellar stair.
The main stair was opened up,  reconfigured and extended to the partial 4th floor, the new was done to match the existing so one cannot tell where the old ends and the new begins.
All the main living areas are on the parlor floor, the second floor remained the same with a master bedroom suite and two bedrooms and bath, except the center hall in now a seating area open to the stair, the third floor has the new master bedroom suite and two smaller bedrooms and a bath, with the family room and a small bath on the fourth floor and a direct access to a large roof terrace.