Residential use shall be permitted in M1-6D Districts only in accordance with the provisions of this Section. For the purposes of this Section, a “qualifying building” shall be any building that existed on April 25, 2011, and which contained at least 40,000 square feet of floor area on such date.

(a)        Residential use as-of-right

Residential use shall be permitted as-of-right on any zoning lot that, on April 25, 2011, was not occupied by a qualifying building. Such absence of a qualifying building on the zoning lot shall be demonstrated to the satisfaction of the Department of Buildings.

(b)        Residential use by certification

Residential use shall be permitted on a zoning lot that, on April 25, 2011, was occupied by one or more qualifying buildings, only upon certification by the Chairperson of the City Planning Commission that the zoning lot will contain at least the amount of non-residential floor area that existed within qualifying buildings on the zoning lot on April 25, 2011, provided that:

(1)        preservation of non-residential floor area within existing non-qualifying buildings on the zoning lot shall not be counted toward meeting the requirements of this certification; and

(2)        floor area from community facility uses with sleeping accommodations shall not be counted toward meeting the requirements of this certification.

However, non-residential floor area converted to residential vertical circulation and lobby space need not be replaced as non-residential floor area.

A restrictive declaration acceptable to the Department of City Planning shall be executed and recorded, binding the owners, successors and assigns to provide the amount of non-residential floor area that existed within qualifying buildings on April 25, 2011, on the zoning lot. Such restrictive declaration shall be recorded in the Office of the City Register. A copy of such declaration shall be provided to the Department of Buildings upon application for any building permit related to a change in use from non-residential to residential, or for a new building containing residences.