In R9 districts, which are mapped along several major thoroughfares in Manhattan, such as West 96th Street, new buildings can be developed under height factor
regulations or the optional Quality Housing
regulations as in R6 through R8 districts. The optional Quality Housing regulations in R9 districts are the same as the R9A regulations. Designed in part for institutional purposes (mainly hospitals), most R9 height factor buildings are developed pursuant to the tower rules
, which are applicable only in the city’s higher-density areas, and commercial districts with an R9 residential district equivalent
(C1‑8, C2-7 and C6-3)..
R9 Height Factor/Tower Regulations
(FAR) for height factor/tower buildings ranges from 0.99 to 7.52 and the open space ratio
(OSR) from 1.0 to 9.0. As in other height factor districts, a taller building can usually be developed by providing more open space. Under the tower rules, however, buildings on both wide and narrow streets are permitted to penetrate the sky exposure plane
. In the diagram, for example, buildings that front on a wide street
must have a contextual street wall
of 60 to 85 feet with a tower above (tower-on-a-base
). The height of the tower is controlled by a minimum lot coverage
requirement and a rule that at least 55% of the floor area on the zoning lot
be located below a height of 150 feet. For buildings with only narrow street
frontage, a contextual base is not required and towers are permitted, provided they are set back from the street line
at least 15 feet.
Off-street parking is not required for any development in the Manhattan Core
or Long Island City.
Elsewhere, parking is required for 40% of dwelling units.