The lawful occupancy of basements and cellars in one-and-two family (private) dwellings, multiple dwellings, including old law tenements (constructed before 1901) and new law tenements (1901-1929), and converted dwellings, are regulated by numerous State and City laws and ordinances. These include the 1968 and 2008 NYC Building Codes (BC) and the Housing Maintenance Code (HMC), all which are in the NYC Administration Code (AC), the Multiple Dwelling Law (MDL) and the NYC Zoning Resolution (ZR). The bottom line for homeowners and landlords is use of a basement or cellar in NYC requires a legal use document recognized by The NYC Department of Buildings (DOB) that designates what type use is legal in the space.
Many basements and cellars cannot be used for habitable living purposes, such as sleeping, showering, eating or primary cooking, because the space fails to meet the numerous and strict statutory requirements, including ceiling height, proper ventilation and natural light, window size and placement in relation to outside open areas, egress and fire prevention, and moisture levels. Use of a cellar for habitable living purposes in one-and-two family homes is prohibited.
Increased scrutiny and prohibition on certain uses of basements and cellars is caused by the dangers of carbon monoxide poisoning from a building’s heat and hot water equipment, safety hazards with close human proximity to heating and electric equipment, inadequate light, ventilation and egress, mold and mildew, sanitation and sewer backflow issues, vermin, and underground moisture levels. Further, the emerging threat of climate change, which brings more frequent and intense rain and storm conditions, increase the risk of basement and cellar flooding. A potential liability for all homeowners and landlords when deciding to use a basement or cellar for habitable or occupiable purposes.
Habitable and Occupiable Spaces and Rooms
The designated type of occupancy, which is the purpose or activity for which a building or space is used or is designed or intended to be used, is similar in both the current Building Code of 2008 (updated in 2014) and the previous Building Code of 1968.
Pursuant to the current Building Code of 2008 (2014) (BC 1202.1), Habitable Space is the designation of rooms and spaces for “bedrooms, living rooms, studies, recreational rooms, kitchens, dining rooms, and other similar spaces.” (Exceptions include bathrooms). Occupiable Space is a room or enclosed space, other than a Habitable Space, designed for human occupancy or use in which individuals may “remain for a period of time for rest, amusement, treatment, education, dining, shopping, employment, labor or other similar purposes.”
Pursuant to the Building Code of 1968 (27-232), a Habitable Room is a residential room or space in which the “ordinary functions of domestic life are carried on, and which includes bedrooms, living rooms, studies, recreation rooms, kitchens, dining rooms and other similar spaces, but does not include closets, halls, stairs, laundry rooms, or bathrooms.” An Occupiable Room is a room or space, other than a Habitable Room designed for human occupancy or use, in which “persons may remain for a period of time for rest, amusement, treatment, education, dining, shopping, or other similar purposes, or in which occupants are engaged at work.”
Pursuant to the Building Code of 1938 (1.83), a Livable Room was “any room used for normal living purposes in a residence structure and shall not include kitchens, laundry rooms, bathrooms or storerooms.” Of note, the Housing Maintenance Code uses Living room, which is “any room within a dwelling unit except a dining space, kitchenette, bathroom or water closet compartment, foyer or private hall, corridor, or passageway.”
Basement and Cellar Units – Multiple Dwellings
A basement or cellar space in a multiple dwelling can legally be habitable for living purposes if all specific code and statutory requirements are met to the satisfaction of the NYC DOB. The determination of occupiable or habitable use is based on the condition and location of the cellar or basement and compliance with the requirements of Building Code, MDL and HMC provisions. The size of the backyard, number of egress points, proof of existing conditions and structure are just a few of the many challenges that must be overcome to satisfy the Project Examiners (PE) at the DOB for approval of an application to legally convert the space to habitable use and receive a Certificate of Occupancy. In practice, cellars rarely meet the conditions for use as a habitable space or rooms.
Basement and Cellar Units – One- and Two-Family Dwellings
There are strict rules for use of basement and cellar spaces in one-and-two family dwellings, and renting of a cellar space is prohibited. Cellars can only be used in conjunction with the dwelling above and only for occupiable uses such as a secondary kitchen (HMC 27-2087(a)). If the building is a two-family dwelling, converting the basement or cellar into another dwelling unit would effectively make the building a multi-dwelling (MDL 4(7)), requiring a legal change in the Certificate of Occupancy (28-210.1) and registration with HPD. (HMC 27-2097). Lastly, a habitable basement in a two-family dwelling can only be used for living purposes by family members in conjunction with the dwelling above the basement. (HMC 27-2087(b)). More common, a one-family dwelling rents out a basement unit, creating a two-family dwelling, as many times these basement units can comply with the law (HMC 27-2087(c)).
Legal Use Documents
The Certificate of Occupancy is recognized by City agencies and The Courts as the official designation of legal use of a building, and supersedes all other documents regardless of date. However, buildings built before 1938 were not required to file a CofO after construction, and the NYC Building Code grandfather’s non-compliance. Without a CofO, other records can be used to prove the use group of a building, starting with the HPD iCard, if available, and then Sanborn Maps. HPD iCards are a record of inspections at various years post construction, and can go back to 1901. Other records and evidence of legal use include letters of no objection, affidavits from current and previous owners, and NYC Department of Finance records.