(a)        Dwelling unit distribution

For developments, enlargements, extensions or conversions of an existing building to a residential use, the density requirements of the underlying districts shall be inapplicable. In lieu thereof, the required lot area per dwelling unit of a development, enlargement, extension or conversion of an existing building to a residential use shall not be less than 168 square feet and the number of two-bedroom units on a zoning lot shall not be less than 20 percent.

In addition, the minimum density requirement and the 20 percent, two-bedroom unit requirement set forth in this Section shall apply to any alteration that creates additional dwelling units or additional zero-bedroom units. Alterations that reduce the percentage of apartments that contain two bedrooms are not permitted unless the resulting building meets the 20 percent, two-bedroom requirement.

However, notwithstanding any provision to the contrary contained in this Section, the minimum density requirement and the 20 percent, two-bedroom unit requirement shall not apply to alterations which add a code-complying bathroom, pursuant to Section 27-2063 of the Housing Maintenance Code of the City of New York, to a dwelling unit which is publicly assisted (exclusive of any tax abatement or tax exemption program), and which is administered by a not-for-profit agent.

The City Planning Commission, by special permit, may modify the two-bedroom unit distribution requirement and the density requirement of this Section for an affordable independent residence for seniors or for a residence substantially for elderly persons with disabilities, under jurisdiction of a State or City agency, provided that the following findings are made:

(1)        that such residences are sponsored by a voluntary non-profit organization;

(2)        that the location and size of such facility does not create an undue concentration of dwelling units of this type and community facilities with sleeping accommodations within the immediate area;

(3)        that there are social service, health and related programs for the residents including a maintenance and security plan;

(4)        that on-site recreation areas for the use of the residents are provided; and

(5)        that the proposed residences will not overburden existing public services in the neighborhood.

The Commission may prescribe appropriate conditions or safeguards to minimize the adverse effect of any use permitted under this Section on the residential character of the surrounding area.

(b)        Special provisions for owner-occupied buildings containing residences

For alterations of buildings containing residences,which buildings are owner-occupied and which contain four or fewer dwelling units, the dwelling unit distribution provisions of this Section shall not apply.