N.Y. Comp. Codes R. & Regs. tit. 9, § 2100.11 – Conversions after May 1, 1950.

(a) Any housing accommodations resulting from conversion of housing accommodations created on or after May 1, 1950 shall continue to be subject to rent control unless the administrator issues an order decontrolling them which he shall do if there has been a structural change in a residential unit or units involving substantial alterations or remodeling; and such change has resulted in additional housing accommodations consisting of self-contained family units, provided, however, that such order of decontrol shall not apply to that portion of the original housing accommodations occupied by a tenant in possession at the time of the conversion, only so long as such tenant continues in occupancy. Such order shall be effective as of the date of the completion of such conversion. Where the date of first renting is prior to the date of completion the landlord may make application for an order establishing a maximum rent pursuant to section 2102.6(a) of this Title. Such maximum rent shall remain in effect until further order of the administrator pursuant to this section.
1. (1) The term self-contained family unit shall mean a housing accommodation with private access, containing two or more rooms, consisting of at least one bedroom and a living room- dining space area in addition to a kitchen (with cooking and refrigeration facilities and a sink), having a minimum total area of 410 square feet for the foregoing rooms, and a private bathroom (with a wash basin, toilet and bathtub or enclosed shower). Such accommodation shall also contain at least one closet plus an additional closet for each bedroom which shall not be included in the computation of the total floor area. In lieu of a kitchen the accommodation may include an enclosed kitchenette or an area in the living room which is either recessed or semienclosed provided that all of the above-specified kitchen facilities and equipment are within such recessed or semi-enclosed area. Where, however, the landlord establishes that either the two-room or total floor area requirement, or both, cannot be complied with because of unique or peculiar circumstances, the administrator may waive this requirement where he finds that such waiver is not inconsistent with the purposes of the act or this Subchapter and would not be likely to result in the circumvention or evasion thereof.
(b) No order of decontrol shall be issued under this section unless such conversion occurred after the entire structure, or any lesser portion thereof as may have been thus converted, was vacated by voluntary surrender of possession or in the manner provided in Part 2104 of this Subchapter and unless the administrator shall find that the landlord has satisfied all of the requirements of the authorities having jurisdiction over such conversion and over the occupancy of the newly created housing accommodations.
(c) Where housing accommodations were or are decontrolled by an order issued pursuant to this section and a municipal department having jurisdiction thereafter certifies the housing accommodations to be a fire hazard or in a continued dangerous condition or detrimental to life or health, such housing accommodations shall be subject to this Subchapter, but only so long as such illegal or hazardous condition continues and without further certification with respect thereto.
(d) No order of decontrol shall be issued by the administrator where there is a conversion of occupied housing accommodations unless and until the landlord obtains an order authorizing subdivision or a certificate of eviction in accordance with the provisions of section 2104.7 of this Title.