In C6-4 Districts within the Park Avenue Hub Subdistrict, as shown on Map 1 in Appendix A of this Chapter, the following provisions shall apply.

(a)        Street wall location

The applicable provisions of Section 35-651 shall be modified as follows:

(1)        Along 125th Street

The minimum base height shall be 60 feet, or the height of the building, whichever is less, except that for buildings or portions thereof within 50 feet of Park Avenue, the minimum base height shall be 40 feet, or the height of the building, whichever is less. The street wall location provisions of this paragraph shall be modified to allow a sidewalk widening pursuant to the provisions of paragraph (a)(2) of this Section; and

(2)        Along Park Avenue and narrow streets

The provisions of paragraph (a) of Section 35-651 shall apply, except that the minimum base height shall be 40 feet, or the height of the building, whichever is less.

In addition, for zoning lots with frontage along Park Avenue between 124th Street and 125th Street, any development or horizontal enlargement shall provide a sidewalk widening along the street line of Park Avenue. Such sidewalk widening shall have a depth of 10 feet, be improved to Department of Transportation standards for sidewalks, and be at the same level as the adjoining public sidewalk.

(b)        Basic maximum building height and setback regulations

The maximum height of buildings or other structures shall be as set forth in Sections 35-652 (Maximum height of buildings and setback regulations) or 35-654 (Modified height and setback regulations for certain Inclusionary Housing buildings or affordable independent residences for seniors), as applicable, except that the minimum base height shall be as set forth in paragraph (a) of this Section, and the maximum base height for buildings or other structures along the street line of 125th Street and within 50 feet of such street line shall be 85 feet.

For the purposes of applying the provisions for qualifying ground floors, the provisions of Section 97-20 (LOCATION AND ACCESS REGULATIONS), inclusive, shall apply in lieu of the applicable provisions of paragraph (b)(2) of Section 35-652.

(c)        Optional height and setback regulations

As an alternative to the provisions of paragraph (b) of this Section, the provisions of this paragraph (c) may be applied to zoning lots meeting the criteria set forth in paragraph (a) of Section 23-664 (Modified height and setback regulations for certain Inclusionary Housing buildings or affordable independent residences for seniors), or zoning lots where 50 percent or more of the floor area is allocated to non-residential uses.

(1)        Setbacks

At a height not lower than the minimum base height specified in paragraph (a) of this Section, nor higher than a maximum base height of 85 feet, a setback shall be provided in accordance with paragraph (c) of Section 23-662 (Maximum height of buildings and setback regulations). Above such required setback, any portion of a building or buildings on the zoning lot shall be considered a “tower.”

(2)        Lot coverage requirements for towers

Each story of a tower containing residential floor area shall not exceed a maximum lot coverage of 40 percent, except that, for zoning lots less than 20,000 square feet, such lot coverage may be increased in accordance with the table in Section 23-65 (Tower Regulations). Each story of a tower allocated exclusively to non-residential floor area shall not exceed a maximum lot coverage of 50 percent. However, where dormers are provided within the required setback, such portions of buildings shall not count toward the maximum allowable lot coverage set forth in this paragraph.

(3)        Maximum building height

No height limit shall apply to towers.