Garage Conversion ADUs in NYC: A Step-by-Step Visual Guide
Got a garage you barely use? You might be looking at your next ADU.
Garage conversions are one of the most popular ADU options in New York City — especially in Staten Island and Queens, where detached garages are common. They're often cheaper than building from scratch, and they can come together faster too. Here's how the process works, step by step.
Step 1: Check If Your Garage Qualifies
Not every garage can become an ADU, but most detached garages can. Here's what matters:
The garage needs to be on the same lot as a one- or two-family home
You (the owner) need to live on the property
The garage can't be in a high-risk flood zone unless you elevate the ground floor
One big advantage of garage conversions: under NYC's zoning rules, they're not classified as "backyard ADUs" or “backyard ancillary dwelling units” if they were legally construction prior to December 4th, 2024, which means they face fewer location restrictions than a brand-new detached structure.
Step 2: Assess the Existing Conditions
Before any construction starts, you need to understand what you're working with:
Ceiling height — Can you get to 7 feet? If not, you may need to dig down or raise the roof.
Square footage — Is there room for a kitchen, bathroom, and living space within the existing space or do you need to enlarge the garage?
Utilities — Will you need to run new electrical, plumbing, and gas lines, or can you tap into existing ones?
Insulation — Garages are typically not insulated. This will need to change.
Structural stability – Is your garage in sound structural shape or does it need structural reinforcements?
Step 3: Design the Layout
This is where it gets fun. A garage conversion ADU typically includes a small kitchen or kitchenette, a bathroom, a living/sleeping area, and enough storage to feel like a real home. Good design makes a huge difference in a small space — smart built-ins, open floor plans, and natural light go a long way. If your garage is less than 300 square feet, you might consider enlarging the footprint or building a second floor.
Step 4: Get Your Permits
You'll need to file with the NYC Department of Buildings. Your design professional and permit expeditor will handle the paperwork after you preparing the full architectural and engineering plans.
Step 5: Build It
Once permits are approved, construction begins. A garage conversion is typically faster than building a new structure — often 2 to 3 months, depending on the scope of work.
Step 6: Get Your Certificate of Occupancy
Before anyone can legally live in your new ADU, it needs to pass inspections and receive a Certificate of Occupancy from the city. Your contractor and design professional will guide you through this final step.
How Much Does a Garage Conversion Cost?
Converting a garage to an ADU in NYC typically costs $150,000–$200,000, depending on the size of the garage, extent of any horizontal or vertical enlargements, and how much work is needed. It's generally on the lower end of ADU costs — which is one reason garage conversions are so popular.
Ready to Turn Your Garage into Something Great?
Send us your address and we’ll take a look at your property. A free assessment will tell you whether a garage conversion is the right move — and a general idea of what it will cost to make it happen.