N.Y.C. Admin. Code § 27-304: § 27-304 Existing excessive area.

Any building existing on December sixth, nineteen hundred sixty-eight that exceeds the maximum allowable area permitted under the provisions of this section, may be enlarged if the addition is separated from the existing building by a fire division meeting the requirements of subchapter five of this chapter, and if the additional area does not exceed the limits established by tables 4-1 and 4-2 for the specific occupancy group and construction class.