Key Project Terms: Loft Law IMD (Alterations)

The following is a list of useful terms to use when researching additional Residential & Community Facilities information on each of the topics discussed:


An alteration is the addition, change of use, or occupancy of a building or structure in existence, and always results in a new or amended Certificate of Occupancy. Work may involve an enlargement, reduction in size of the building, or a major change to the building egress, zoning use group, and/or Building Code occupancy use. Currently, the filing of a DOB Alteration Type 1 application would be needed.


As defined in the Multiple Dwelling Law (MDL), that part of a multiple dwelling consisting of one or more rooms that contain at least one bathroom and are arranged to be occupied by the members of a family. An apartment’s room or rooms are separated and set apart from all other similar apartments with rooms within a multiple dwelling.


As defined in the MDL, a person who is regularly engaged in the fine arts, such as painting and sculpture or in the performing or creative arts, including choreography and filmmaking, or in the composition of music on a professional basis, and is so certified by the Department of Cultural Affairs (DCLA) or other appropriate agency of the City of New York.


A story partly below the curb level, but having at least one-half of its height above the curb level; except that where every part of the building is set back more than twenty-five feet from a street line, the height shall be measured from the adjoining grade elevations calculated from final grade elevations taken at intervals of ten feet around the exterior walls of the building. A basement shall be counted as a story in determining height.


An enclosed space having more than one-half of its height below the curb level; except that where every part of the building is set back more than twenty-five feet from a street line, the height shall be measured from the adjoining grade elevations calculated from final grade elevations taken at intervals of ten feet around the exterior walls of the building. A cellar shall not be counted as a story.

‘Class A’ Multiple Dwelling

A multiple dwelling that is occupied for permanent residence purposes. This class shall include tenements, flat houses, maisonette apartments, apartment houses, apartment hotels, bachelor apartments, studio apartments, duplex apartments, kitchenette apartments, garden-type maisonette dwelling projects, and all other multiple dwellings except class B multiple dwellings. A class A multiple dwelling shall only be used for permanent residence purposes. For the purposes of this definition, permanent residence purposes shall consist of occupancy of a dwelling unit by the same natural person or family for thirty consecutive days or more and a person or family so occupying a dwelling unit shall be referred to herein as the permanent occupants of such dwelling unit.

Code and Zoning Pre/Determinations

Determination requests are submitted to the Borough Commissioner's office for an objection raised by a plan examiner or a possible future objection for an application not yet filed (pre-determination). To request a determination, file a Zoning Resolution Determination Form (ZRD1 Form) (ZRD1 Instructions) or a Construction Code Determination Form (CCD1 Form) (CCD1 Instructions). Forms must be signed and sealed by a professional. Determination requests are limited to one per form and must cite all related code or zoning sections.


Commercial establishments include occupancy classifications listed in Building Code (2014 BC) section 309 Group M - Mercantile and B - Business which include, but are not limited to, department stores, drug stores, markets, motor fuel-dispensing facilities, retail or wholesale stores, sales rooms, banks, barber and beauty shops, civic administration offices, offices, post offices, etc.

Per the Zoning Resolution, Commercial, as applied to a building’s use, is any retail, service or office use. For example, Use Group 6 consists primarily of retail stores and personal service establishments. Commercial can also describe the type of zoning district, i.e. having a ‘C’ prefix.

Curb Level

For the purpose of measuring the height of any portion of a building, with respect to ZR and MDL, is the level of the curb at the center of the front of the building; except that where a building faces on more than one street, the curb level is the average of the levels of the curbs at the center of each front. Where no curb elevation has been established the average elevation of the final grade adjoining all exterior walls of a building, calculated from grade elevations taken at intervals of ten feet around the exterior walls of the building, shall be considered the curb level, unless the city engineer shall establish such curb level or its equivalent.


Any building or structure or portion thereof which is occupied in whole or in part as the home, residence or sleeping place of one or more human beings.

Floor Area

As used in MDL Article 7B, gross floor area shall be measured to the outside surface of exterior walls and includes shafts and stairways and similar. However, clear floor area or interior floor area is measured to the interior finish surfaces of walls, typically within a room or dwelling unit.

Frame Dwelling

A dwelling in which the exterior walls, or any structural parts of such walls, are of wood


As applied to a part or parts of a building, means such part or parts are made of non-combustible materials with standard fire-resistive ratings not less than those required for the corresponding part or parts of a fireproof dwelling.

Fireproof Multiple Dwelling

One in which the walls and other structural members are of non-combustible materials or assemblies meeting all of the requirements of the building code and with standard fire-resistive ratings of not less than one of the following sets of requirements:

  1. For any multiple dwelling more than one hundred feet in height, four hours for fire walls, party walls, piers, columns, interior structural members which carry walls, girders carrying columns, and for exterior walls other than panel walls; three hours for other girders, fire partitions, floors including their beams and girders, beams, roofs, floor fillings, and stairway enclosures; and two hours for exterior panel walls.
  1. For any multiple dwelling one hundred feet or less in height, the provisions of preceding paragraph a shall apply, except that the minimum requirements shall be three hours for exterior walls other than panel walls, which shall be two hours; two hours for protection of interior columns; one and one-half hours for roofs and for floors and beams; provided, however, that for a multiple dwelling three stories or less in height, the requirement for all floors and the roof shall be one hour.

High Rise Building

A building with an occupied floor located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access. See BC 403.

Home Occupation

Certain accessory uses to residential dwelling unit, as described in ZR 12-10.

Interior Mezzanine/Interior Balcony

As used in the MDL, an interior mezzanine, or interior balcony, is an intermediate level between the floor and ceiling of any story. Limitations on the floor area and height of an interior mezzanine, or Interior balcony, within IMDs are discussed in MDL 277.

Interim Multiple Dwelling (IMD)

MDL §281 sets forth the criteria for becoming a Loft Building, also known as an interim multiple dwelling (IMD), as adjudicated by the Loft Board. MDL 280 states that IMDs are de facto multiple dwellings, meaning that IMDs are lawfully existing, which is a design consideration, even though the legalization process, i.e. the process to ensure statutory compliance as required to get a Certificate of Occupancy, may not have started.

Joint Living Work Quarters for Artists (JLWQA)

A type of loft unit, as described in MDL Article 7B, Zoning Use Group of 17D; an artist is a person who is regularly engaged in the fine arts or in the performing or creative arts, and who is certified by the city department of cultural affairs and/or state council on the arts.

Letter of No Objection (LNO)

Before owner can obtain permit to do any other work within building, but not directly related to the IMD unit(s), the owner must get a LNO from the Loft Board.

Loft Board

The New York State Legislature established the New York City Loft Board, a nine-member board appointed by the Mayor, in 1982 to regulate the conversion of certain buildings that were constructed for commercial and manufacturing use to lawful residential use.

Loft Board Certification

Prior to obtaining a permit for work needed to legalize the IMD unit(s), once the owner resolves all objections and issues between such owner and the occupants, the Loft Board shall issue a letter certifying compliance with all Loft Board requirements, and has no objections.


Manufacturing establishments include occupancy classifications listed in Building Code (2014 BC) Section 306, Group F which include, but are not limited to, moderate and low hazard factories, industrial processing plants, contractor facilities, auto & boat repairs, clothing manufacture, food processing, wrecking establishments, laboratories, etc., and BC 307 Group H which include, but are not limited to, the processing, manufacturing, or storage of materials which represent a high physical hazard or health hazard.

Per the Zoning Resolution, Manufacturing, as applied to a building’s use, is a building with high performance standards, such as Use Group 17 for lower hazard industrial uses, Use Group 18 for higher hazard industrial uses, or Use Group 16 for semi-industrial uses. Manufacturing can also describe the type of zoning district having an ‘M’ prefix.

Minor Alterations and Ordinary Repairs

As defined in AC 28-105.4.2, Minor Alterations are minor changes or modifications in a building or any part thereof, excluding additions thereto, that do not in any way affect health or the fire or structural safety of the building or the safe use and operation of the service equipment therein. Such work may not be done in any manner that violates the provisions of the Construction Codes, the Zoning Resolution or any other law or rules enforced by the Department.

As defined in AC 28-105.4.2, Ordinary Repairs are replacements or renewals of existing work in a building, or of parts of the service equipment therein, with the same or equivalent materials or equipment parts, that are made in the ordinary course of maintenance and that do not in any way affect health or the fire or structural safety of the building or the safe use and operation of the service equipment therein. Ordinary repairs shall include the repair or replacement of any plumbing fixture, piping or faucets from any exposed stop valve to the inlet side of a trap.

Minor alterations and ordinary repairs do not include any of the work described as work not constituting minor alterations or ordinary repairs, as described elsewhere in AC 28-105.4.2.
NOTE: Minor alterations or ordinary repairs, if done concurrently with any application work that requires a permit, must be clearly indicated in such application’s drawings and be part of the scope of work. Such application scope of work requires a permit, for which a fee is calculated.

Mixed Building

Per ZR 12-10, a mixed building is a building in a commercial district used partly for residential use and partly for community facility and/or commercial use, but not manufacturing.

Mixed Use/Mixed Occupancy

Per the Building Code, a building with a mixed use would contain two or more occupancy classifications.

Multiple Dwellings

As defined in the Multiple Dwelling Law, a multiple dwelling is a building which is either rented, leased, let or hired out, to be occupied, or is occupied as the residence or home of three or more families living independently of each other. Multiple Dwellings are basically divided into two classes: Class A (non-transient) and Class B (transient).

Non-conforming Use

A Zoning term. A non-conforming use is any lawful use of a building or other structure, or a space within a building, on a zoning lot, which does not conform to any one or more of the applicable use regulations of the zoning district in which it is located, either on December 15, 1961, or as a result of any subsequent amendment thereto.

Non-fireproof Dwelling

One which does not meet the requirements for a fireproof

Occupancy Classification

The use as defined in the Building Code, is a category or class designation based on the purpose or activity for which a building or space is used or is designed, arranged or intended to be used.

Public Hall

A hall, corridor or passageway within a building but outside of all apartments

Rear Yard

As defined in the Multiple Dwelling Law, an open space on the same lot with a dwelling between the extreme rear line of the lot and the extreme rear wall of the dwelling. A side yard is a continuous open space on the same lot with a dwelling between the wall of a dwelling and a line of the lot from the street to a rear yard or rear line of a lot. A court is an open space other than a side or rear yard, on the same lot as a dwelling. A court not extending to the street or rear yard is an inner court. A court extending to the street or rear yard is an outer court.


Changes to an existing building, including the remodeling or replacing of outdated or damaged structure and materials, and the partial demolition of interior partitions; building renovations can also include the installation or replacement of building systems, devices or equipment, materials or parts, as part of regular maintenance of the building. Renovation projects shall not impact the existing means of egress, change the use of the building or space, and change the occupant load.


An enclosed space extending through one or more stories of a building connecting a series of openings therein, or any story or stories and the roof, and includes exterior and interior shafts whether for air, light, elevator, dumbwaiter, enclosed vertical stairways, or any other purpose.

Tax Lot

A tax lot is used to describe a tract of property on the city’s tax map on which property taxes are assessed.

Use Group

The Use Group (UG), as defined in the Zoning Resolution (ZR) section 12-10, is a category or group with specific purpose(s) for which a building or other structure, or an open tract of land may be designed, arranged, intended, maintained or occupied; furthermore, the use is any activity, occupation, business or operation carried on, or intended to be carried on.

Zoning Lot

A zoning lot is a tract of land for which specific zoning regulations apply. A zoning lot does not have to coincide with a tax lot, and can consist of one tax lot or multiple tax lots.

Key Points & Project Terms Categories

  1. Alterations

  2. Building Systems Installation & Modifications

  3. Construction Equipment

  4. Demolition COMING SOON!

  5. New Buildings COMING SOON!

  6. Renovations

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