What it costs to build an ADU in Hastings-on-Hudson, NY

Marine Waterfront - Lot size and the yards here also have to satisfy the Hudson River waterfront access and preservation rules for the GI and MW districts (§ 295-80A), so the figures shown are not the whole test. The 20% coverage cap counts all buildings and structures together.

• On a corner lot the street-facing side yard must be as deep as the required front yard or 15 ft, whichever is greater (§ 295-20F).
• A side yard longer than 50 ft has to widen by 1 ft for every 10 ft of length beyond 50 ft (§ 295-20G).
• The ZBA may cut the front yard where there is pronounced uniformity of shallower front yards within 250 ft on the same side of the street (§ 295-20D(2)).
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Marine Waterfront-A - The lot minimum is dry land: 20,000 sq ft of dry land area and 150 ft of width, and the 20% building coverage is 20% of the lot's dry land too, so submerged acreage counts toward neither (§ 295-83).

• Height is not measured from grade: three stories, and no more than 30 ft above elevation 10, so on ground already higher than that less than 30 ft is available.
• The Planning Board may cut the front, rear and side yards as part of site plan approval (§ 295-83F(2)), so the yards shown are the starting point.
• A sports or health club follows different limits: 50 ft above elevation 10, coverage capped at 60,000 sq ft rather than a percentage, and the front, rear and side yard requirements do not apply to it.
• The 0.09 floor area ratio is an aggregate cap on all residential development across the whole district, counting dry land only, not a limit that can be applied to one lot.
• The Planning Board's view preservation review reaches this district (§ 295-83G(1)) and can reshape a building that meets every figure shown.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.

Marine Waterfront-B - The 25 acres is not a lot minimum. It is what an owner needs to petition to have land rezoned to MW-B: 25 or more contiguous acres of dry land with at least 3,000 ft of Hudson River frontage. The district publishes no front, side or rear yards, only a shoreline setback.

• The shoreline setback is at least 100 ft, or 60 ft along the easterly inland side of a pre-existing cove, with no buildings, structures or visible equipment inside it (§ 295-84F(7)(a)).
• As a condition of the rezoning the Village Board may add up to 250 ft to that 100 ft setback and up to 200 ft to the 60 ft one where buildings are tall.
• Height is 65 ft above elevation 10 rather than above grade, and only 50 ft for a sports or health facility; the Village Board may raise it to 103 ft by special use permit after a public hearing.
• The 25% coverage is 25% of total dry land area, excluding any esplanade over water, and at least 50% of the dry land must stay open space for pedestrian use.
• The 0.725 floor area ratio is carved up: at most 0.065 for a sports or health club, and at most 0.095 in aggregate for nonresidential use other than the club and required community space.
• Both the floor area ratio and the 15.5 units per acre are the base rather than the ceiling, since each may rise under the incentive density provisions of § 295-84I.

One-Family Residence - The 35 ft height is the pitched-roof limit. A flat roof is capped at 24 ft and two stories, and a separate wall height of 23 ft applies at the low point of the roof, which dormers may break over up to 25% of the building perimeter.

• The 15% building coverage and 25% development coverage are for a single-family dwelling; every other use gets one 15% cap on all buildings and structures together (§ 295-67F(2)(b)).
• Floor area ratio comes from Appendix B and is keyed to lot area: 0.225 for a lot over 20,000 sq ft, rising to 0.510 for a lot under 3,500 sq ft, so a smaller lot gets more, not less.
• Accessory buildings are capped at 15 ft with a pitched roof and 12 ft with a flat one; rear yard relief runs 8 ft generally, 15 ft for garden, tool, play and greenhouses and 20 ft for swimming pools.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The ZBA may cut the front yard where there is pronounced uniformity of shallower front yards within 250 ft on the same side of the street (§ 295-20D(2)).
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Two Family Residence - The figures shown are the one-family case. A two-family dwelling, the use the district is named for, needs 10,000 sq ft and 100 ft of width (§ 295-70D), a 30 ft front yard, 12 ft on each side and 30 ft combined, and a rear yard of 30 ft or 30% of the lot depth, whichever is less.

• That rear yard is a ceiling rather than a floor: on a lot 80 ft deep it resolves to 24 ft.
• The 35 ft height is the pitched-roof limit; a flat roof is capped at 24 ft and two stories, and a separate wall height of 23 ft applies at the low point of the roof.
• Building coverage of 30% and development coverage of 40% are for a single-family dwelling; a two-family or any other use gets one 25% cap on all buildings and structures.
• Floor area ratio is not a single figure here: Appendix B keys it to lot area, 0.510 for a lot under 3,500 sq ft falling to 0.225 for a lot over 20,000 sq ft.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

One-Family Residence - The 30 ft rear yard is a ceiling as well as a floor: it is 30 ft or 30% of the lot depth, whichever is less, so on a lot 90 ft deep the requirement is 27 ft rather than 30 ft.

• The 35 ft height is the pitched-roof limit; a flat roof is capped at 24 ft and two stories, and a separate wall height of 23 ft applies at the low point of the roof.
• The 25% building coverage and 35% development coverage are for a single-family dwelling; every other use gets one 25% cap on all buildings and structures together (§ 295-68F(2)(b)).
• Floor area ratio is not a single figure here: Appendix B keys it to lot area and prints 0.325 at the 10,000 sq ft district minimum, falling as the lot grows.
• Accessory buildings are capped at 15 ft with a pitched roof and 12 ft with a flat one.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

One-Family Residence - The 35 ft height is the pitched-roof limit. A flat roof is capped at 24 ft and two stories, and a separate wall height of 23 ft applies at the low point of the roof, which dormers may break over up to 25% of the building perimeter.

• The 30% building coverage and 40% development coverage are for a single-family dwelling; every other use gets one 30% cap on all buildings and structures together (§ 295-69F(2)(b)).
• Side yards must total 20 ft with at least 8 ft on either one, and accessory buildings also keep 8 ft.
• Floor area ratio is not a single figure here: Appendix B keys it to lot area and prints 0.375 at 7,500 sq ft, falling to 0.225 for a lot over 20,000 sq ft.
• Accessory buildings are capped at 15 ft with a pitched roof and 12 ft with a flat one.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Two Family Residence - The figures shown are the one-family case. A two-family dwelling needs 5,000 sq ft and 50 ft of width (§ 295-70.1E), 10 ft on each side and 25 ft combined, and a rear yard of 20 ft or 30% of the lot depth, whichever is less.

• That rear yard is a ceiling rather than a floor, so on a shallow lot the requirement comes out below 20 ft.
• For a single-family dwelling the 10 ft front yard may drop to 2 ft where an unenclosed porch encroaches.
• The 35 ft height is the pitched-roof limit; a flat roof is capped at 24 ft and two stories, and a separate wall height of 23 ft applies at the low point of the roof.
• The 50% building coverage and 60% development coverage are for a single-family dwelling; all other uses get one 50% cap.
• No FAR is published for this district; unlike R-20, R-10, R-7.5 and 2R it carries no Appendix B cross-reference.
• A through lot fronting both Ridge Street and Southside Avenue, with access only from Southside Avenue, may be developed to the MR-C standards instead, capped at 40 ft or three stories (§ 295-70.1G).

Multi-Family Residence/Office - The 6 ft of combined side yard is only for a lot at the district's 25 ft minimum width. The combined total climbs with width: 9 ft at 30 to 39 ft, 12 ft at 40 to 49, 16 ft at 50 to 59, 20 ft at 60 to 69, 24 ft at 70 to 79 and 30 ft at 80 ft or more. One side is always 3 ft.

• The rear yard is 20 ft, cut to 15 ft where the first floor is a nonresidential use.
• The number of dwelling units is not a land-per-unit rule: the floor area the ratio allows for dwelling units is divided by 1,000 and rounded to the nearest whole number (§ 295-72.1E(5)).
• The 500 sq ft minimum is per dwelling unit in a multifamily or mixed-use residential building, not a whole-house minimum.
• Parking: none required on a lot under 40 ft wide, and 0.8 spaces per unit at 40 ft and above.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Multi-Family Residence - The 1,500 sq ft is land per dwelling unit, not a lot minimum. The district publishes no flat minimum lot area at all, so the lot has to carry 1,500 sq ft for every unit in the building, alongside the 25 ft minimum width.

• The front yard is 12 ft or half the height of the building wall nearest the front lot line, whichever is greater, so a 40 ft wall owes 20 ft.
• Side yards grow with lot width: 2 ft each and 5 ft total at 25 to 49 ft, 2 ft each and 10 ft total at 50 to 74, 5 ft each and 15 ft total at 75 to 99, and 10 ft each and 20 ft total at 100 ft or more.
• No building may exceed 160 ft in length.
• Accessory structures are capped at 15 ft with a sloped roof and 12 ft with a flat one, and the 8 ft rear-yard relief needs the accessory wall to stay under 6 ft.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Multi-Family Residence - The code publishes no minimum lot size and no minimum lot width for MR-2.5; the subsection that carries them in the neighbouring districts reads as reserved. The yards are the constraint instead: a 100 ft front yard, 40 ft rear, and 40 ft on each side totalling 80 ft.

• Height is 35 ft and no more than two stories.
• Coverage is a single 25% cap on all buildings and structures together.
• No building or structure on the lot may exceed 160 ft in length.
• A multifamily dwelling for three or more families must also provide 100 sq ft of recreation and open space per studio unit plus 200 sq ft per bedroom.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Multi-Family Residence/Commercial - The 30 ft rear yard and 10 ft side yard apply only where the lot is adjacent to a residential district, and there is no front yard requirement.

• The 40 ft and three-story height is also subject to a slope envelope, stepping down in 20 ft runs toward the rear lot line (§ 295-72.2E(3)); on a sloping lot that envelope binds first.
• Coverage is one 80% cap on all buildings and structures together.
• The 500 sq ft minimum is per dwelling unit in a mixed-use building or a dwelling for three or more families, not a whole-house minimum.
• On a corner lot the street-facing side yard must equal the required front yard or 15 ft, whichever is greater, and a side yard longer than 50 ft widens 1 ft for each 10 ft beyond 50 ft.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Central Commercial - No front yard is required unless the Planning Board finds one necessary to preserve river or Palisades views or traffic flow, and then it can be up to 10 ft.

• A 10 ft side yard is required where the lot is adjacent to a residence district or a one- or two-family dwelling; otherwise no side yard is required.
• The rear yard is 10 ft at the ground floor and 20 ft above it, rising to 30 ft where the side or rear of the lot is adjacent to a residence district.
• The 40 ft and three-story height is subject to a stepped slope envelope toward the rear lot line (§ 295-76E(4)).
• A residential unit in a mixed-use building must be at least 500 sq ft, and the ground floor has to stay nonresidential.
• Construction and alterations must also conform to the Board of Trustees' design guidelines for the CC district.
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

Central Office - The 30% coverage cap counts all buildings and structures on the lot together, not just the house, and the Planning Board's view preservation review (§ 295-82C) can reshape a building that meets every figure shown.

• Side yards must total 25 ft, with at least 10 ft on either one.
• On a corner lot the street-facing side yard must be as deep as the required front yard or 15 ft, whichever is greater (§ 295-20F).
• A side yard longer than 50 ft has to widen by 1 ft for every 10 ft of length beyond 50 ft (§ 295-20G).
• The ZBA may cut the front yard where there is pronounced uniformity of shallower front yards within 250 ft on the same side of the street (§ 295-20D(2)).

Limited Commercial - Both side yards have to be at least 20 ft, and height is capped at 35 ft and two stories. The 50% coverage cap counts all buildings and structures on the lot together.

• On a corner lot the street-facing side yard must be as deep as the required front yard or 15 ft, whichever is greater (§ 295-20F).
• A side yard longer than 50 ft has to widen by 1 ft for every 10 ft of length beyond 50 ft (§ 295-20G).
• The ZBA may cut the front yard where there is pronounced uniformity of shallower front yards within 250 ft on the same side of the street (§ 295-20D(2)).
• The Planning Board's view preservation review applies here (§ 295-82C) and can reshape a building that meets every figure shown.

General Industry - Any side yard with a driveway between the building and the lot line must be at least 25 ft (§ 295-78).

Limited Industry - Any side yard adjacent to a residence district or a one- or two-family dwelling must be at least 40 ft.

• All parking and loading must be set back at least half of the required yard.

Mixed Use Planned Development - The front, side and rear figures are site perimeter setbacks measured to the edge of the seven-acre site, not yards from each lot line, and nothing inside them may be paved except driveways and walkways giving access.

• A further 50 ft setback applies from a designated trailway or other significant environmental feature.
• Height is three stories or 40 ft, whichever is less.
• Density is capped two ways at once: six dwelling units per acre and twelve bedrooms per acre, so a three-bedroom programme is bedroom-limited below six units.
• Both caps may rise by up to 33 1/3% where land is dedicated for open space or recreation and the Board of Trustees finds the dedication sufficient, which is within its absolute discretion.
• Land dedicated that way is excluded from lot area when building and development coverage are computed, and does not reduce the open space requirement.
• Approval runs in two phases: a concept plan from the Board of Trustees, then site plan approval.

Public Park, Recreation and Playground - Every Village-owned park, playground and recreation area dedicated as a public park is in the PR district. No building, structure or use is permitted unless the Board of Trustees authorizes it after a public hearing.

• The permitted uses are only those necessary to preserve and promote the purposes of the park.
• The code publishes no lot size, yards, height or coverage for this district, so there is no by-right development to dimension.

Gateway Cluster Overlay District - A cluster subdivision here must keep a buffer of 150 ft along every street frontage and 50 ft around the rest of its perimeter, with no structures in it except entrance roads and driveways.

• The Planning Board may modify the minimum lot size, width, required yards and coverage for a cluster subdivision, so those are not fixed minimums.
• The one thing it may not modify is the maximum building height, which stays the underlying district's.
• Permitted uses follow the underlying district, and density may not exceed what that district's lot size and density rules would allow.
• A cluster plan is required for any parcel of four acres or more here, and the Planning Board may require one below four acres.

Multimedia Production Studio Overlay - These figures apply only to a multimedia production studio. Every other use on the parcel follows the R-20 district, and the overlay reaches a parcel only if it is in R-20, exceeds 10 acres and fronts Broadway (NYS Route 9).

• The front yard is 150 ft along Broadway or Tompkins Avenue, but only 50 ft on any other street frontage.
• The Planning Board may reduce any of these yards to accommodate a preexisting building, or where the new building sits next to a property that is not a developed residential lot.
• The overlay reaches a parcel only when the Board of Trustees grants a petition reviewed as a zoning amendment (§ 295-157), with a conceptual site plan, traffic and fiscal studies and a landscape plan.
• A new driveway entrance structure such as a gate must sit at least 100 ft back from the Broadway frontage.
• Site plan approval carries performance standards, including no more than two active productions at a time and a film permit for any outdoor filming.

Personal Wireless Facilities Overlay District - This overlay adds wireless facility standards to whatever district lies underneath and publishes no lot size, yards, coverage or building height of its own, so the dimensional answer for a parcel is the underlying district's (§ 295-85).

• A tower or monopole may reach 125 ft above ground level, and an antenna on another structure 6 ft above that structure's highest point, in each case only by special permit from the Planning Board.
• New facilities and any addition or modification to an existing one are confined to this overlay, except that § 295-85N allows a special permit for a site outside it.

View Preservation Overlay - This overlay publishes no schedule of its own: uses and dimensions follow the district the lot is in. What it adds is a review of a structure's siting, dimensions and configuration to cause the least possible obstruction of the Hudson River and Palisades view (§ 295-82).

• No building or structure may be erected, altered, enlarged or moved without approval; the application goes from the Building Inspector to the Planning Board, which has 60 days to report.
• The review reaches the whole Village, and a report can reshape a building that satisfies every figure shown for its district.