An ADU builder in Buffalo 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 Buffalo'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 Buffalo [7][8]
Based on our Buffalo 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) | $110,000-$220,000 |
| Cost per Sq Ft | $120-$250 |
| Garage Conversion | $55,000-$130,000 |
| Prefab / Modular ADU (installed) | $80,000-$180,000 |
| City Permit & Plan Review | Building-permit fees are set on construction value; the current schedule was not retrievable online - confirm with Permit & Inspection Services. Zoning fees (OSP memo eff. July 1, 2025): area variance $150 (1-2 units), minor site plan $350, special use permit $350. |
| Impact Fees | None - the UDO contains no development impact fee; confirm any water or sewer connection charges with Buffalo Water. |
For a full line-item breakdown, see our Buffalo ADU cost guide. To confirm what you're allowed to build before you hire, review the Buffalo ADU rules (max detached size: 1,000 sq ft gross floor area max; a detached ancillary dwelling must also be lower in height (feet) and smaller in footprint than the principal building, and must meet the Sec. 3.2.3 carriage-house standards (UDO Sec. 6.1.2.B).; owner-occupancy: Not required by the UDO - Sec. 6.1.2.B has no owner-occupancy or rental restriction. (BURA's Plus One ADU funding program does require owner-occupancy for grant recipients.)).
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How to Vet an ADU Builder in Buffalo
- 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 Buffalo 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 (Building-permit fees are set on construction value; the current schedule was not retrievable online - confirm with Permit & Inspection Services. Zoning fees (OSP memo eff. July 1, 2025): area variance $150 (1-2 units), minor site plan $350, special use permit $350.), plan check (Not published; part of the building-permit review by Permit & Inspection Services.), and impact fees (None - the UDO contains no development impact fee; confirm any water or sewer connection charges with Buffalo Water.) are included.
- Permit handling: Confirm they manage Buffalo's permit process ("Building permit from the Department of Permit & Inspection Services (register the project, then plan review against the NYS Uniform Code and the UDO). A detached unit is reviewed against the Sec. 3.2.3 carriage-house standards; anything short of a standard needs an area variance from the Zoning Board of Appeals.", typically Not published - the city does not post plan-review times for residential permits; ask Permit & Inspection Services when you register the project.) 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 Buffalo 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 (Not published - the city does not post plan-review times for residential permits; ask Permit & Inspection Services when you register the project.) 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?
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