Berne · ADU cost
What it costs to build an ADU in Berne, NY
An 800 sq ft accessory dwelling unit in Berne runs roughly $195k–260k, or about $247–323/sq ft, and that per-square-foot figure sits deliberately above the $202–265/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 Berne maps 9 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 Berne
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Albany County pricing, before the service and septic work a second dwelling can trigger.
| Size | Type | $ / sq ft | Estimated total |
|---|---|---|---|
| 400 sq ft | Studio | $327–$428 | $130k–170k |
| 600 sq ft | One bedroom | $273–$358 | $165k–215k |
| 800 sq ft | One bedroom, larger | $247–$323 | $195k–260k |
| 1,000 sq ft | Two bedroom | $231–$302 | $230k–300k |
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 | $27–$33 | $16 | 55% |
| Electrical | $18–$23 | $13 | 35% |
| HVAC | $23–$28 | $14 | 45% |
| Insulation | $7–$9 | $7 | — |
| Interior finishes | $32–$43 | $27 | 15% |
| Millwork & cabinetry | $18–$27 | $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 Berne 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 |
|---|---|---|---|---|
| Medium Density Residential | 1.5 ac | 40 / 50 / 100 ft | 35 ft | No |
| Neighborhood Commercial | 1.5 ac | 40 / 20 / 50 ft | 35 ft | No |
| Reforestation Area | — | — | — | — |
| Historic | — | — | — | — |
| General Commercial | 1.5 ac | 70 / 40 / 50 ft | 35 ft | No |
| Industrial | 10 ac | 150 / 300 / 100 ft | 35 ft | No |
| Residential/Agricultural/Forestry | 5 ac | 70 / 100 / 100 ft | 35 ft | No |
| Traditional Neighborhood/Mixed Use 1 | 0.25 ac | 15 / 20 / 50 ft | 35 ft | No |
| Traditional Neighborhood/Mixed Use 2 | 0.25 ac | 15 / 20 / 50 ft | 35 ft | No |
Medium Density Residential - These figures are the residential case. A nonresidential use takes a 140 ft front yard instead of 40 ft and 250 ft of lot width instead of 200 ft, while the 1.5 acre lot minimum and the 50 ft side and 100 ft rear yards stay the same.
Neighborhood Commercial - These figures are the residential case. A nonresidential use takes a 140 ft front yard instead of 40 ft and 250 ft of lot width instead of 100 ft, while the 1.5 acre lot minimum and the 20 ft side and 50 ft rear yards stay the same.
Reforestation Area - RA is a mapped overlay lying over land otherwise zoned RAF, covering much of the town's south end. Which dimensional standards apply to a parcel under it is not confirmed, so settle that with the building department before counting on any building envelope.
- The overlay appears on the official zoning map (190 Attachment 3, dated 7-9-2007), which § 190-5 makes an appurtenant part of the zoning chapter.
- RA is not among the districts listed in § 190-4, so ask the building department how the overlay is administered on a private application.
- Ask the building department whether the underlying RAF standards govern lot size, setbacks and coverage for land marked by the overlay.
- The town's comprehensive plan, a separate planning document, uses the term reforestation area for state-owned forest land; the zoning chapter does not say so in terms.
Historic - H works as a design and appearance review layer and sets no lot size, setback, coverage or height figure of its own. A parcel in H is governed by whatever base district underlies it, so the figures depend on where the parcel sits on the zoning map.
- Exterior features, materials and scale, along with demolition, are reviewed by the Planning Board against the district's architectural character (§ 190-21.C).
- District boundaries are those shown on the zoning map (§ 190-21.A(2)).
- Confirm with the building department which base district, such as RAF or MDR, applies to a given parcel before sizing a project.
General Commercial - A residential lot in GC needs the same 1.5 acres of area but only 100 ft of width, so the 250 ft width applies to the nonresidential case.
- The density schedule prints two side yard figures for this district, 40 ft and 20 ft, and does not define which one applies; confirm the side yard with the building department.
- Height is capped at 3 stories as well as 35 ft.
- A note attached to this district in the density schedule points to the mobile home park standards in § 190-38.
Industrial - There is no mapped Industrial area. Under § 190-20 the Town Board may approve industrial development of a parcel in the RAF district and establish an Industrial District there, after Planning Board review, public notice and hearing.
- The approval acts as an overlay, superimposing the Industrial standards on the underlying district for that approved site in place of the RAF standards.
- No residential use is allowed under § 190-20.C(2)(a), apart from a caretaker's dwelling or a residential use that predates the Industrial District's establishment on that site.
- The schedule prints a second side yard figure of 200 ft next to the larger one, and neither § 190-10 nor § 190-16 says which applies, so confirm the side yard with the building department.
Residential/Agricultural/Forestry - These figures are the residential case. A nonresidential use needs 8 acres rather than 5 and a lot at least 400 ft wide rather than 300 ft, while the 70 ft front yard applies either way.
Traditional Neighborhood/Mixed Use 1 - Without sewer service the lot minimum is 1.5 acres rather than 0.25 acre. The front yard is a band as well, 15 ft minimum and 30 ft maximum, so a building cannot sit further back than 30 ft.
- A nonresidential use also needs 1.5 acres, and its building coverage may reach 65% against the 25% a house is held to.
- A nonresidential use in an existing building takes the acreage of the existing lot instead, so a change of use does not make an undersized lot noncompliant.
- A new nonresidential building's footprint is capped at 2,000 sq ft; no footprint maximum applies to a house.
Traditional Neighborhood/Mixed Use 2 - Without sewer service the lot minimum is 1.5 acres rather than 0.25 acre. The front yard is a band as well, 15 ft minimum and 50 ft maximum, so a building cannot sit further back than 50 ft.
- A nonresidential use also needs 1.5 acres, and its building coverage may reach 65% against the 25% a house is held to.
- A nonresidential use in an existing building takes the acreage of the existing lot instead, so a change of use does not make an undersized lot noncompliant.
- A new nonresidential building's footprint is capped at 3,000 sq ft; no footprint maximum applies to a house.
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. Berne has no confirmed local short term rental rule. That is not the same as permission, so confirm with the building department before counting on renting a home short term here. Separate question from whether you can build the unit.
- Zoning codeecode360.com/BE2069
- Building dept(518) 872-1448
Sizing up a specific parcel in Berne?
Aldo pulls the exact zoning district, setbacks, and build feasibility for any parcel — before you buy. Enter your email to open Aldo and run your free report.
Building a full house instead?
A standard-finish house in Berne runs $202–265/sq ft, about $365k–475k at 1,800 sq ft , plus roughly $5,874 for a conforming lot. See what it costs to build a house in Berne.
ADU cost in nearby towns
All Albany County towns: Albany (City) · Cohoes (City) · Watervliet (City) · Bethlehem · Coeymans · Colonie · Guilderland · Knox · New Scotland · Rensselaerville · Westerlo · Altamont (Village) · Colonie (Village) · Green Island (Village) · Menands (Village) · Ravena (Village) · Voorheesville (Village)
More on Berne: Can you build an ADU here? · Zoning for new construction · Albany County build cost
ADU cost in Berne: common questions
How much does it cost to build an ADU in Berne, NY?
An 800 sq ft accessory dwelling unit in Town of Berne runs roughly $195k–260k at a standard finish, general-contractor margin included. A 400 sq ft studio runs about $130k–170k. 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 Berne?
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 $247–323/sq ft against $202–265/sq ft for a full house, even though it is the same trades doing the same work.
Are ADUs allowed in Berne?
Town of Berne has 9 districts. 7 of 9 districts prohibit ADUs. 2 districts have incomplete data - verify with the building department at (518) 872-1448. Check the specific address with the free ADU checker before you spend money on design.
Can I rent an ADU in Berne short term?
No local short-term-rental law on record - which is not the same as permission for Town of Berne. 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 Albany 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 Berne vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-09-20; verify with the building department at (518) 872-1448 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.