Turning your basement into a legal living space in NYC is a great idea. You can create an additional income stream, add value to your home, or have a space for guests when it’s not rented out.
However, there’s legal considerations. Basement apartments, also called cellar apartments or less commonly English basements, require a little extra work to create a space that’s legal to rent out.
In this article, you’ll learn:
- Whether you can legally live in a basement in NYC
- Legal Requirements for Basement Apartments
- NYC Zoning and Permit Considerations
- How to Design a Compliant Space
- Why Work with a Professional Contractor
Can You Legally Live in a Basement in NYC?
While sometimes these spaces are referred to as “cellar apartments,” you cannot legally live in a cellar. Legally, a basement is defined as a story built below curb level with at least half its height above curb level.
A cellar, on the other hand, has more than half its height below curb level. Cellars are not allowed to be used for residential use. This generally means they can’t be used as spaces for sleeping or cooking, though a homeowner with a cellar can use the space for other purposes, like storage space.
If you have a basement, you can remodel it into a standalone apartment. But there are considerations and legal requirements you’ll need to know first.
Legal Requirements for Basement Apartments
Basement apartments have legal requirements set by the NYC Department of Building. You’ll need to keep these factors in mind to ensure your basement is compliant:
Minimum ceiling height must be at least 7 feet. If your basement doesn’t have a ceiling that meets this height, it’s not eligible to be rented out.
Egress windows and exits must be suitable for use as an emergency escape. Every designated sleeping room in the basement apartment, as well as the unit as a whole, must have an emergency escape route. In addition, these spaces also need a “rescue opening” which can be a window or door that leads directly outdoors. Egress windows must be at minimum 24” height by 20” wide. If any part of the window is below grade, there must be an accessible window well that’s at least 36” high and wide. If more than 44” deep, a ladder may be required.
Fire safety and sprinkler systems must be installed in basement units for compliance and safety. This includes both smoke and carbon monoxide alarms. Automatic sprinkler systems are not required yet, but new rules propose making them mandatory.
Proper ventilation and natural light are vital to create a healthy and comfortable place to live. Every room in a basement apartment must have at least one window. The area of all the windows in a room must be at least one-eighth of the floor area. Ventilation is also required in each room, with openable windows that are at least 4% of the floor area. Finally, kitchens have specific ventilation requirements: kitchens over 80 square feet but have natural ventilation (windows) that open to at least 5% of the floor area. Kitchenettes less than 80 square feet must have mechanical ventilation like a range hood that vents air outside.
Plumbing, heating, and electrical standards are the same as any other apartment. Alterations to plumbing must be carried out by a licensed professional and properly permitted. Apartment owners must provide heating from October through May, hot water year-round, and ensure temperatures fall within a defined range.
NYC Zoning and Permit Considerations
Adding a legal basement apartment turns a single-family home into a multifamily property in some districts, including R3A, R4-1, and R4B. This means the building must comply with multifamily regulations, which are often stricter.
In other zones, a basement apartment in a single or two-family residence is considered an accessory dwelling unit 9 (ADU). The owner must reside on the property in either the main house or the ADU to avoid the reclassification.
Co-ops and condo associations often have extremely strict rules about what can be done on the property. Rarely do these types of buildings allow basement apartments.
Please note: these statements are not intended to be legal advice. Basement apartments in NYC are still highly regulated. If you are interested in a basement apartment, we can help you learn about specific rules and regulations based on your zone and property.
Permitting
NYC has strict permitting standards. To convert a basement into a legal apartment, you will need to hire a Registered Design Professional (RDP), such as an architect or engineer, to draft plans and submit the permit application to the building department. After successful submission and approval, you will be awarded a certificate of occupancy.
How to Design a Comfortable, Code-Compliant Basement Living Space
Maximize Light
Tenants don’t want basement apartments to feel like basements. Optimize natural light by reconfiguring layouts to avoid blocking windows, adding main living areas by natural light sources, and by decorating with colors and materials that bounce light throughout the apartment. If it’s possible within your scope of work, install new windows, replace interior doors with french doors and sheer curtains, or eliminate unnecessary partition walls.
Design Intentional Layouts
Beyond opening up the layout for natural light, consider how to maximise space with intentional design. For a studio, use partial walls or built-in storage to separate the sleeping area from the rest of the space. Consider multifunctional spaces, like a kitchen area with a counter that doubles as a table.
Install Moisture Control Measures
Basements have the reputation of being damp. To avoid this, consider installing a permanent dehumidifying system. In addition, a vapor barrier — a plastic covering to prevent moisture intrusion — is legally required for basement apartments.
Why Work With a Professional Contractor
Illegal basement apartments are not uncommon, but get caught with one and you’ll be facing fines from the city and legal battles from your tenants. Ensure this doesn’t happen to you by working with a local pro that knows the permitting process, legal requirements, and zoning regulations.
MTK Contracting has been operating in NYC for home additions, renovations, apartment updates, and more. Get in touch with us to learn more about transforming your unused basement into a compliant, safe, and comfortable apartment.
