The floor area ratio provisions of Sections 23-14 (Open Space and Floor Area Regulations in R1 Through R5 Districts) and 23-15 (Open Space and Floor Area Regulations in R6 Through R10 Districts), inclusive, shall be modified for certain areas, as follows:

(a)        For standard tower and tower-on-a-base buildings in R9 and R10 Districts

(1)        In R9 Districts, for zoning lots where buildings are developed or enlarged pursuant to the tower-on-a-base provisions of Section 23-651, the maximum floor area ratio shall be 7.52, and the maximum lot coverage shall be 100 percent on a corner lot and 70 percent on an interior lot.

(2)        In R9 and R10 Districts, for zoning lots containing a building that is developed or enlarged pursuant to the applicable tower regulations of Section 23-65 (Tower Regulations), inclusive, any floor space used for mechanical equipment provided pursuant to paragraph (8) of the definition of floor area in Section 12-10 (DEFINITIONS), and any floor space that is or becomes unused or inaccessible within a building, pursuant to paragraph (k) of the definition of floor area in Section 12-10, shall be considered floor area and calculated in accordance with the provisions of this Section, provided that such floor space:

(i)        occupies the predominant portion of a story;

(ii)        is located above the base plane or curb level, as applicable, and below the highest story containing residential floor area; and

(iii)        exceeds an aggregate height of 25 feet within any given 75 vertical feet of one another within a building.

For the purpose of applying this provision, the height of such floor space shall be measured from the top of a structural floor to the bottom of a structural floor directly above such space. In addition, the number of stories of floor area such space constitutes within the building shall be determined by aggregating the total height of such floor spaces, dividing by 25 feet, and rounding to the nearest whole integer.

(b)        For R10 Districts in Community District 7 in the Borough of Manhattan

Within the boundaries of Community District 7 in the Borough of Manhattan, in R10 Districts, except R10A or R10X Districts, the maximum floor area ratio shall be 10.0. No floor area bonuses shall be permitted except as granted by the City Planning Commission pursuant to the provisions of Section 66-51 (Additional Floor Area for Mass Transit Station Improvements).

(c)        For R8 Districts in Community District 9 in the Borough of Manhattan

Within the boundaries of Community District 9 in the Borough of Manhattan, all buildings located in R8 Districts north of West 125th Street shall be developed or enlarged pursuant to the Quality Housing Program and are subject to the floor area regulations set forth in Section 23-153 (For Quality Housing buildings).

(d)        Optional provisions for certain R5 and R6 Districts in Community District 12 in the Borough of Brooklyn

Within the area bounded by 39th Street, Dahill Road, Ditmas Avenue, McDonald Avenue, Bay Parkway, 61st Street and Fort Hamilton Parkway in Community District 12, in the Borough of Brooklyn, special optional provisions are established for zoning lots containing buildings used exclusively as single-, two- or three-family residences, as set forth in this Section. Except as modified by the express provisions of this Section, the regulations of R5 and R6 Districts remain in effect.

(1)        Floor area, lot coverage, open space, density and height factor regulations

Where the optional provisions of this Section are applied, the regulations of Article II, Chapter 3, relating to floor area ratio, open space, density and height factor are hereby made inapplicable. In lieu thereof, the maximum floor area ratio for a corner lot shall not exceed 1.65 and the floor area ratio for an interior or through lot shall not exceed 1.8 in R5 Districts and 1.95 in R6 Districts. Notwithstanding the definition of floor area in Section 12-10, the lowest story shall be included in the definition of floor area, and floor space used for accessory off-street parking spaces shall be included in the definition of floor area unless such spaces are located in a cellar. The lot coverage for a corner lot shall not exceed 55 percent and the lot coverage for an interior or through lot shall not exceed 60 percent in R5 Districts and 65 percent in R6 Districts.

(2)        Building height

No building shall exceed a height of 35 feet above curb level, or three stories, whichever is less. Where the optional provisions of this Section are applied, the regulations of Article II, Chapter 3, relating to height and setback, are hereby made inapplicable, except that the provisions of Section 23-62 (Permitted Obstructions) shall apply.

(3)        Front yards

In R5 Districts, the following front yard regulations are applicable. A front yard shall be provided with a depth of not less than five feet provided that, for corner lots, one front yard with a depth of not less than 10 feet is required. If the depth of the front yard exceeds 10 feet, such front yard shall have a depth of not less than 18 feet. In R6 Districts, a front yard is not required.

(4)        Side yards

In R5 Districts, the following side yard regulations shall apply:

(i)        Where an existing building on an adjacent zoning lot is located on the common side lot line, no side yard is required. However, if an open area extending along such common side lot line is provided, it shall be at least eight feet wide.

(ii)        Where an existing building on an adjacent zoning lot is located less than eight feet from, but not on, the common side lot line, a side yard at least four feet wide is required. However, in no case shall the distance between a new or enlarged building and an existing building across a common side lot line on an adjacent zoning lot be less than eight feet.

(iii)        Where an adjacent zoning lot is vacant or where an existing building on an adjacent zoning lot is located more than eight feet from the common side lot line, a side yard at least four feet wide is required.

(iv)        In R6 Districts, a side yard is not required. However, when a building is 62 feet or more in depth, an eight foot side yard or an outer court, as set forth in paragraph (d)(6) of this Section, is required.

(v)        Notwithstanding the provisions of paragraphs (d)(1) and (d)(3) of this Section, detached single-, two- and three-family residences on corner lots shall provide side yards of five feet and 20 feet. Semi-detached single-, two- and three-family residences on corner lots shall provide one side yard of 20 feet.

(5)        Rear yards

Single- or two-family residences consisting of detached, semi-detached or zero lot line buildings may project up to 10 feet into a required rear yard or rear yard equivalent, provided that there is a side yard of at least eight feet for such semi-detached or zero lot line buildings, and that the total width of side yards for a detached building is at least eight feet.

(6)        Outer court and minimum distance between legally required windows and walls or lot lines

In R6 Districts, the outer court provisions of Section 23-84 are modified as follows: an outer court shall have a minimum width of 10 feet and a depth of not more than twice the width.

Where a building is attached, along a common side lot line, to a portion of an existing or new building on an adjacent zoning lot, there may be a joint outer court with a minimum width of 10 feet across such common side lot line. The requirements of Section 23-86 (Minimum Distance Between Legally Required Windows and Walls or Lot Lines) are hereby made inapplicable.

(7)        Off-street parking in R5 and R6 Districts

No accessory off-street parking is required in R5 and R6 Districts.