An ADU builder in New York City is a licensed contractor who designs and constructs accessory dwelling units — detached backyard units, garage conversions, attached additions, and junior ADUs (JADUs). Because an ADU is a complete second dwelling, the builder coordinates foundation, framing, plumbing, electrical, and HVAC work and pulls it through New York City's permit process and utility connections. Not every general contractor has built one, so the right builder is one with ADU-specific experience in New York.
What ADU Builders Cost in New York City [3][4]
Based on our New York City cost data, expect the following ranges from local ADU builders. Quotes for the same scope typically vary 20-40% between contractors, so getting at least three bids is the single best way to control cost.
| New Detached ADU (all-in) | $150,000-$300,000 |
| Cost per Sq Ft | $300-$600 |
| Garage Conversion | $120,000-$260,000 |
| Prefab / Modular ADU (installed) | Rarely feasible (site access/crane limits) |
| City Permit & Plan Review | $5,000-$10,000 |
| Impact Fees | Varies by borough |
For a full line-item breakdown, see our New York City ADU cost guide. To confirm what you're allowed to build before you hire, review the New York City ADU rules (max detached size: Up to 800 sq ft (and no more than 33% of the required rear yard) where permitted under City of Yes; not allowed in historic districts or R1A/R2A/R3A zones outside the Greater Transit Zone; owner-occupancy: Owner must occupy either the primary home or the ADU).
Get Free ADU Quotes in New York City
Tell us about your project and we'll connect you with ADU builders serving New York City. Free, no obligation — you choose who to work with.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
How to Vet an ADU Builder in New York City
- License: Confirm a current contractor's license in New York and that it's in good standing. Ask for the license number and verify it with the state board.
- ADU-specific experience: Ask how many ADUs they've completed in or near New York City and request addresses or photos. ADU permitting and setbacks differ from a kitchen remodel.
- Portfolio & references: Get references from recent ADU clients and, if possible, visit a finished unit.
- Insurance: Verify general liability and workers' compensation coverage. Ask for a certificate of insurance.
- Written, detailed bid: Insist on an itemized, fixed-price or clearly-scoped bid — not a verbal estimate. It should state whether permits ($5,000-$10,000), plan check (6-8 weeks), and impact fees (Varies by borough) are included.
- Permit handling: Confirm they manage New York City's permit process ("DOB NOW: Build filing (Alt-CO-GC or New Building-GC job with Ancillary Dwelling Unit section); pre-approved plan designs get streamlined review", typically 120-180 days) and who is responsible if revisions are required.
- Payment schedule: Avoid large upfront payments. A reasonable schedule ties payments to completed milestones.
Questions to Ask Before You Hire
- How many ADUs have you built in New York City in the last two years?
- Is your bid fixed-price, and what would trigger a change order?
- Are permits, plan check, and utility connection fees included?
- What's a realistic timeline, including permit review (120-180 days) and construction?
- Who is my point of contact and how are delays communicated?
- What warranty do you provide on workmanship?
- Can you share three recent New York ADU client references?
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Are you an ADU builder? Get New York City leads
Homeowners on this page submit real ADU project requests in New York City. We match each one to a local builder. Your first lead is free, then a small per-lead fee — no subscription, and you contract directly with the homeowner.
Get New York City ADU Leads →Frequently Asked Questions
How much do ADU builders charge in New York City?
How do I find a good ADU builder in New York City?
Do ADU builders in New York City handle permits?
How long does it take to build an ADU in New York City?
Get Free ADU Builder Quotes in New York City
Compare bids from experienced local New York City ADU builders. Free, no obligation.
Get Free Quotes →