Concord · ADU cost
What it costs to build an ADU in Concord, NY
An 800 sq ft accessory dwelling unit in Concord runs roughly $200k–260k, or about $249–327/sq ft, and that per-square-foot figure sits deliberately above the $204–268/sq ft a full house costs here. An ADU still needs one whole kitchen, one whole bath, its own service panel and its own heating plant no matter how small you draw it, and those costs do not shrink with the floor plan, so they land on half the square footage and push the rate up. Whether the town will let you build one is a separate question from what it costs, and it gets answered parcel by parcel rather than townwide, since the Town of Concord maps 15 districts that treat accessory units differently from one another, so read the table below as a starting point rather than a verdict.
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ADU cost by size in Concord
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Erie County pricing, before the service and septic work a second dwelling can trigger.
| Size | Type | $ / sq ft | Estimated total |
|---|---|---|---|
| 400 sq ft | Studio | $331–$433 | $130k–175k |
| 600 sq ft | One bedroom | $276–$362 | $165k–215k |
| 800 sq ft | One bedroom, larger | $249–$327 | $200k–260k |
| 1,000 sq ft | Two bedroom | $233–$305 | $235k–305k |
400 sq ft — One room plus a bath. Garage conversions and small backyard cottages land here.
600 sq ft — The most common detached build - a real bedroom, full kitchen, one bath.
800 sq ft — Room for a proper living area. Still a single bath and one kitchen.
1,000 sq ft — About as large as most codes allow an accessory unit to go.
Why the rate is higher than a house
The systems below are priced for an 800 sq ft unit. The middle column is what each system would cost if it simply shrank with the floor plan; the left column is what it actually costs once you account for the equipment a dwelling needs one of regardless of size. The gap between the two columns is the whole reason small builds price the way they do.
| System | $ / sq ft in an ADU | If it scaled with floor area | Fixed per unit |
|---|---|---|---|
| Site work | $7–$11 | $7 | — |
| Foundation | $16–$23 | $16 | — |
| Framing | $25–$32 | $25 | — |
| Envelope - roof, siding, windows | $32–$41 | $32 | — |
| Plumbing | $28–$34 | $16 | 55% |
| Electrical | $18–$24 | $13 | 35% |
| HVAC | $23–$28 | $15 | 45% |
| Insulation | $7–$9 | $7 | — |
| Interior finishes | $32–$43 | $27 | 15% |
| Millwork & cabinetry | $18–$28 | $11 | 55% |
The fixed-per-unit share is a modeling assumption, not a figure from the code: it is our estimate of how much of each system's budget buys equipment a dwelling needs exactly one of - a kitchen rough-in, a bath group, a service panel, a heating plant - and therefore does not shrink when the unit does. Site work, foundation, framing, envelope and insulation are treated as scaling straight with floor area, which understates the premium slightly, because a small building carries more envelope per square foot of floor than a large one.
What the Concord code says about accessory units
Whether you can build one, and how large, is decided by the district your parcel sits in rather than by the town as a whole. The table shows how each mapped district treats ADUs alongside the lot and setback standards a second unit still has to fit inside. District boundaries and conditions vary, so treat it as a starting point and confirm the district that applies to your parcel.
| District | Min lot | Setbacks F / S / R | Max height | ADU |
|---|---|---|---|---|
| R-E Single-Family Residential Estate District | 2 ac | 50 / 15 / 50 ft | 35 ft | No |
| R-1 Single-Family Residential District | 2 ac | 50 / 15 / 50 ft | 35 ft | No |
| R-2 General Residential District | 2 ac | 50 / 15 / 50 ft | 35 ft | No |
| General Residence-Mobile Home Court District | — | 50 / 15 / 5 ft | 35 ft | No |
| Residential-Agricultural District | 3 ac | 50 / 15 / 50 ft | 35 ft | No |
| Residence-Restricted Business District | 2 ac | 50 / 15 / 35 ft | 35 ft | No |
| Craneridge District | 0.34 ac | 35 / 15 / 35 ft | 35 ft | No |
| Cluster Housing | 0.28 ac | 35 / 15 / 35 ft | 35 ft | No |
| Local Retail Business District | 1 ac | 50 / 0 / 10 ft | 50 ft | No |
| General Commercial District | 1 ac | 50 / 15 / 10 ft | 50 ft | No |
| Commercial-Tourist District | — | 100 / 35 / 35 ft | 35 ft | No |
| Commercial-Recreation District | 50 ac | 50 / 15 / 50 ft | 35 ft | No |
| General Industrial District | — | 40 / 10 / 10 ft | — | — |
| Mining-Reclamation District | — | — | — | No |
| Planned Industrial District | — | — | — | No |
General Residence-Mobile Home Court District - Inside a mobile home court the lot size, the height and every yard come from the town's separate mobile home court regulations rather than from these figures. Outside a court the chapter sets these yards and this height, and no lot area or lot width at all.
Residential-Agricultural District - The 50 ft rear setback is the figure for a dwelling: a structure that is not a dwelling takes only five feet. Farm buildings have no height limit at all, while a dwelling stops at two and a half storeys and 35 ft.
- A garage may come within twenty feet of the edge of the right-of-way where the Planning Board reviews it and the Town Board approves, against the ordinary 50 ft front setback
Residence-Restricted Business District - A duplex needs no more land than a house here, two acres either way, while a building of three or more dwelling units needs three.
- The 35 ft rear setback is the figure for a dwelling; a structure that is not a dwelling takes only five feet
- A principal building that is not a dwelling takes the same 15 ft side yards as one that is, and its height is set by the yard requirements rather than by a figure
- An accessory building stops at one storey and 15 ft
Craneridge District - No building permit or certificate of occupancy may issue until the required public utilities are installed and operational. The only permitted principal use is a single detached house that is not a mobile home.
- The front setback is measured from the edge of the nearest right-of-way, whether that right-of-way is public or private
- A private garage may sit only to the rear of the front setback line
- The district itself must cover at least ten acres and may not be mapped inside the incorporated Village of Springville
Cluster Housing - The front setback is measured from the edge of the nearest right-of-way, public or private. No building permit or certificate of occupancy issues until the public water and sewer serving the district are installed and working.
- The 15 ft side yards and the 35 ft rear yard are for a dwelling; a non-dwelling structure takes 5 ft at the rear
- A dwelling's ground floor must be at least 700 sq ft
- Accessory structures are limited to one story and 15 ft
- The district may be mapped only on an area of at least 10 acres served by public water and sewer
- Single-family detached dwellings may be clustered on a subdivision plat the Town Board approves
Local Retail Business District - No side yard is required for a building that is not a dwelling, but a side yard actually provided must be at least five feet, and 20 ft or the height of the principal building against a residential district boundary.
- A side yard used for vehicular ingress or egress must be at least 25 ft
- A dwelling takes a 15 ft side yard, and a building of three or more dwelling units must stand 40 ft from any property line rather than taking separate yards
- A three-or-more-family dwelling is priced per unit at 15,000 sq ft, which is what governs an apartment scheme rather than the acre
General Commercial District - A building of three or more dwelling units is sized by a flat 15,000 sq ft lot minimum here, not by a figure per unit, and it must stand 40 ft from any property line rather than taking separate yards.
Commercial-Tourist District - The minimum lot size is not a figure: § 150-88 makes it subject to site plan approval and Town Board approval. A hotel may reach one hundred feet here, where every other use stops at 35 ft.
- At least 50 ft of the 100 ft front setback must be devoted exclusively to landscaping, and only one freestanding identification sign is allowed in it
- Against a residential district boundary the side and rear setbacks are also 100 ft, with 50 ft of that landscaped
- Against any other district the side setback is 35 ft or the height of the principal building, whichever is greater
Commercial-Recreation District - The lot minimum depends on what is being built: fifty acres for a campground or recreational vehicle park, and one hundred for a ski centre or resort, commercial horseback riding stable or trail.
- The 50 ft rear setback is the figure for a dwelling; a structure that is not a dwelling takes only five feet
General Industrial District - The side and rear yards jump against a neighbour: 75 ft, or the height of the principal building if greater, against a residential district boundary, and 25 ft against a Local Retail Business district boundary.
- The 40 ft front setback rises to fifty where the lot lies opposite a residential district boundary or where the front is used for accessory parking
- No lot area and no height limit are published here; the lot standard is stated as 100 feet in width
- Required side and rear yards may be used only for landscaping and off-street parking, and lot lines abutting those districts must be fenced or screened
Mining-Reclamation District - The town publishes no dimensions for this district: setbacks from property boundaries and public thoroughfare rights-of-way are specified in the state mining permit rather than in the zoning chapter.
- Access barriers, dust control and hours of operation are set by that permit as well
- The town keeps the routing of mineral transport vehicles on its own roads and a part in the state review of a mining permit application
- The Town Supervisor may make a determination on whether mining is permitted at the location at all
Planned Industrial District - This district publishes no lot area, lot width, yard, height or coverage standard of any kind. The envelope is settled instead when a plan is evaluated for compatibility with adjacent industrial and non-industrial districts.
- Light manufacturing and lumber yards need Planning Board approval against the performance standards
- Retail sale of products manufactured on site needs a Planning Board recommendation and Town Board approval
Costs an ADU adds that a house does not
- Septic and water A second dwelling adds bedrooms to the design flow, which on an unsewered parcel often means expanding or replacing the existing system rather than tapping it. This is the single most common reason an ADU budget moves after design, and it is site-specific enough that no model should quote it - get it evaluated early.
- Utility service National Grid territory. A detached unit needs power run to it, and whether it goes on its own meter or subfeeds the main house changes both the cost and the permit path.
- Access and parking Many codes require an added parking space for the accessory unit, and a detached unit usually needs a driveway extension or a path, both of which count against a lot-coverage or impervious-surface cap.
- Short-term rentalsNo local short-term-rental law on record - which is not the same as permission. Concord has no local short-term rental law. That is not the same as permission, so confirm with the town before counting on renting a home short term. Separate question from whether you can build the unit.
- Zoning codeecode360.com/8073246
- Building dept(716) 592-4946
Sizing up a specific parcel in Concord?
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Building a full house instead?
A standard-finish house in Concord runs $204–268/sq ft, about $370k–480k at 1,800 sq ft , plus roughly $1,103 for a conforming lot. See what it costs to build a house in Concord.
ADU cost in nearby towns
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More on Concord: Can you build an ADU here? · Zoning for new construction · Erie County build cost
ADU cost in Concord: common questions
How much does it cost to build an ADU in Concord, NY?
An 800 sq ft accessory dwelling unit in Town of Concord runs roughly $200k–260k at a standard finish, general-contractor margin included. A 400 sq ft studio runs about $130k–175k. Those are structure costs on an easy site and do not include the septic, water or electrical service work a second unit often triggers.
Why does an ADU cost more per square foot than a house in Concord?
Because a lot of a dwelling's cost is per dwelling, not per square foot. One kitchen, one bath group, one service panel and one heating plant cost about the same in an 800 sq ft cottage as in a 1,800 sq ft house, so on the smaller unit they get spread over less than half the floor area. That is why an ADU here prices at $249–327/sq ft against $204–268/sq ft for a full house, even though it is the same trades doing the same work.
Are ADUs allowed in Concord?
Town of Concord has 15 districts. 14 of 15 districts prohibit ADUs. 1 district has incomplete data - verify with the building department at (716) 592-4946. Check the specific address with the free ADU checker before you spend money on design.
Can I rent an ADU in Concord short term?
No local short-term-rental law on record - which is not the same as permission for Town of Concord. ADU rules and short-term-rental rules are set separately, so a unit you are allowed to build is not automatically one you are allowed to rent nightly. Confirm both before you underwrite the build on short-term-rental income.
ADU costs are modeled estimates in current 2026 dollars at the Erie County regional index, general-contractor margin included, derived from Offsite's cost engine with a stated adjustment for the equipment a dwelling needs one of regardless of size. They are planning numbers for decision-support only - not a bid, quote, or guarantee, and not legal, architectural or engineering advice. They cover the structure and exclude septic expansion, utility service runs, site work beyond a flat and clear pad, and permit fees. ADU eligibility, size, owner-occupancy and permit conditions in the Town of Concord vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-09-10; verify with the building department at (716) 592-4946 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.