Today is the first day of spring. For a lot of NYC homeowners, that means calling a contractor, ordering materials, or finally starting the project that's been on the list since October.
Before you do anything, read this. The city doesn't care that you didn't know you needed a permit. The fines are real, the stop-work orders are real, and selling a home with unpermitted work is a nightmare you don't want.
Here's what requires a permit in New York City, what you can actually do without one, and how to avoid the mistakes that derail renovation projects every spring.
The Basic Rule
In New York City, the Department of Buildings (DOB) requires a permit for virtually any work that involves structural changes, changes to building systems (plumbing, electrical, HVAC), or changes to a building's use or occupancy.
The DOB issues two main types of permits:
New Building (NB) permits — new construction only
Alteration permits — any change to an existing structure
Alteration permits come in three categories:
Alt-1: Major changes — changing the occupancy, egress, or zoning use of a building
Alt-2: Significant structural or systems work (most major renovations fall here)
Alt-3: Minor work that doesn't affect primary structure or occupancy (smaller jobs)
Most homeowner renovation projects — adding a bathroom, finishing a basement, replacing windows — fall under Alt-2 or Alt-3.
What Requires a Permit (The List Nobody Reads Until It's Too Late)
Structural work:
Any work that involves walls, beams, columns, floor joists, or foundation. This includes: removing a wall (even a non-load-bearing one in some buildings), adding a partition wall, modifying stairways, adding dormers or skylights, building a deck attached to the structure.
Electrical:
Any new circuits, subpanel installation, adding outlets to a dedicated circuit, upgrading your electrical service (100A to 200A), or anything that requires opening walls. Replacing an existing outlet or light switch? No permit. Adding a new circuit to run a hot tub, EV charger, or air conditioning unit? Permit required.
Plumbing:
Relocating a sink, toilet, or bathtub. Adding a new bathroom. Installing a new water heater (in most cases). Replacing a waste stack. Simple faucet and fixture replacements? No permit.
HVAC:
Installing central air conditioning, replacing a boiler, adding new ductwork, installing a mini-split system (which is now the most common home cooling upgrade in NYC). Cleaning and servicing existing equipment? No permit.
Fences:
In NYC, fences over six feet tall require a permit. Most fences don't — but call your borough DOB office if you're unsure. Rules differ slightly for corner lots.
Sheds and garages:
Any accessory structure over 144 square feet requires a permit. This catches a lot of homeowners who buy a large prefab shed from Home Depot and don't realize it needs to be filed.
Finished basements:
This is the big one. Converting an unfinished basement into a habitable space — a bedroom, a rental unit, a home office with a bathroom — requires an Alt permit, a certificate of occupancy amendment, and compliance with egress and ceiling height requirements. Many basement apartments in NYC are illegal specifically because the homeowner did the work without filing. This creates serious liability if a tenant is ever injured or in a fire.
What You Can Do Without a Permit
Painting (interior and exterior)
Wallpaper and flooring installation
Cabinet and countertop replacement (no moving of plumbing)
Like-for-like fixture replacements (faucets, toilets, light fixtures — no new circuits)
Landscaping (within property boundaries, not affecting drainage)
Installing a fence under six feet
Most cosmetic work that doesn't touch walls, systems, or structure
If in doubt: the DOB's BIS (Buildings Information System) at bis.buildings.nyc.gov lets you look up any property's permit history, open violations, and active work applications. It's free and public.
How to Pull a Permit
For most Alt-3 work, a licensed contractor who is registered with the DOB can pull the permit on your behalf. You don't have to do this yourself.
For Alt-2 work (more significant renovations), you'll need a licensed architect or engineer to file plans with the DOB before work begins. The process:
Hire a licensed architect or PE to prepare plans
Plans are submitted to DOB via DOB NOW (the online filing system)
DOB reviews and approves (or requests changes)
Permit is issued — work can begin
Required inspections happen during construction
Work is signed off when complete
Timing: the simplest Alt-3 permits can be pulled same-day. A full Alt-2 with plan review can take 2–6 weeks if you're using standard review, or faster with professional certification (where the architect self-certifies the plans comply with the code, subject to audit).
Important: Work that begins before a permit is issued is a violation. You can be fined, and the DOB can issue a Stop Work Order that shuts down the job until you're in compliance.
Borough-Specific Notes
Brooklyn and Queens: Brownstones and attached row houses are the most common project type. Basement conversions are heavily scrutinized because of the number of illegal basement apartments. The Brooklyn DOB borough office has been actively issuing violations for unpermitted basement habitation following a 2023 flooding fatality in a Queens basement apartment.
The Bronx: Older building stock means more surprises inside walls — asbestos, lead paint, aging electrical. Any work that opens walls in a pre-1980 building requires testing before disposal of materials. This is not optional.
Manhattan: Landmarked buildings (managed by the NYC Landmarks Preservation Commission) require LPC approval before any exterior work — windows, doors, stoops, façade material. If your building has a plaque, check before you do anything visible from the street.
Staten Island: The island has more single-family homes than any other borough and accordingly more DIY renovation projects. The Staten Island DOB office is smaller and wait times for inspections can run longer in spring. File early.
The Unpermitted Work Problem at Sale
If you do work without a permit and then try to sell your home, the title search will reveal the discrepancy between your actual building and what's on the certificate of occupancy. Your buyer's attorney will ask about it. Your buyer's lender may refuse to finance until it's resolved.
Resolving it after the fact — called "legalizing" unpermitted work — usually requires hiring an architect to file retroactive plans, passing inspections, and paying fees and sometimes fines. It can cost thousands of dollars and take months. Doing it right the first time is almost always cheaper.
Practical Checklist for Spring Projects
Before any contractor starts work:
Check the DOB permit requirement — use the DOB's online resources or ask your contractor directly
Verify your contractor's license — search at nyc.gov/consumers (Home Improvement Contractor license required for most residential work over $200)
Confirm the contractor will pull the permit — make it a line item in the contract
Ask to see the permit posted at the job site — it's legally required
Schedule inspections in advance — for Alt-2 work, inspections are required at specific milestones. Don't close walls before the in-wall inspection.
Keep copies of everything — approved plans, permits, inspection sign-offs. You'll want these when you sell.
Spring is a great time to finally get the projects done. It's also peak season for the shortcuts that turn into expensive problems two years from now. The permit is not bureaucratic nonsense — it's a paper trail that protects your investment.
The Metro Intel covers money, housing, and local intelligence for New Yorkers across all five boroughs. Subscribe for free at themetrointel.com.