Can you build an ADU in Clarkstown, NY?

Conservation Density Residence - The building coverage cap shown is not the hard ceiling it looks like: under Note 49 a site may exceed it by up to half without a variance where drainage is addressed.

• Any use for which standards are not otherwise specified falls under a separate row: 280,000 square feet of lot area on 250 feet of lot width.
• Those same uses require 75 feet in front, 80 feet to each side with 160 feet for both sides combined, and 160 feet to the rear.
• Height here is written as a sky exposure slope from the designated street line, but Note 38 replaces that calculation in residential districts with the flat 35 feet shown.

Low Density Residence R-80 - Building coverage is not the hard ceiling it looks like: under Note 49 a site may exceed the coverage cap by up to half without a variance where drainage is addressed. The 30 ft side yard also cannot be used on both sides, since the pair must total 80 ft.

• Uses for which standards are not otherwise specified follow another row: 140,000 square feet on 250 ft of width, 75 ft front, 60 ft to each side and 140 ft for the pair, 80 ft rear.
• Height is written as a sky exposure slope, inches of building for each foot of distance from the designated street line, but Note 38 sets a flat 35 ft ceiling in the residential districts.

Low Density Residence R-40 - The building coverage cap is not a hard ceiling. Under Note 49 a site may exceed it by up to half without a variance where drainage is addressed. Side yards must also total 70 ft combined, so 30 ft on each side falls 10 ft short.

• Uses for which standards are not otherwise specified follow a separate row: 100,000 square feet of lot area on 200 ft of width, 60 ft front, 40 ft each side and 100 ft combined, 80 ft rear.
• Height is written as a sky exposure slope, inches of building for each foot of distance from the designated street line, but Note 38 sets a flat 35 ft ceiling in the residential districts.

Medium Density Residence R-22 - Building coverage can run up to half above the 20% cap without a variance where drainage is addressed, under Note 49. The two side yards must add up to 50 feet, so a matching pair of 20 foot sides falls ten feet short.

• Uses for which standards are not otherwise specified follow a different row: 80,000 square feet on 175 feet of width, 50 feet in front, 40 feet to each side, 90 feet for the pair, 60 feet to the rear.
• Height is otherwise set by a sky exposure slope, inches of building for each foot of distance from the designated street line, but Note 38 holds residential districts to a flat 35 feet.
• A deck attached to the house without a permanent roof is not treated as a projection into the side or rear yard.

Medium Density Residence R-15 - The building coverage figure shown is not the hard ceiling it looks like: under Note 49 a site may exceed the cap by up to half without a variance where drainage is addressed.

• Height is written as a sky-exposure slope based on distance from the designated street line, but Note 38 overrides it in the residential districts with the flat 35 ft ceiling shown.
• A use for which standards are not otherwise specified follows a separate row: 80,000 square feet on 175 ft of width, 50 ft front, 40 ft each side and 90 ft for the pair, 60 ft rear.
• A deck attached to the house without a permanent roof is not treated as a projection into the side or rear yard.

Medium High Density Residence - The building coverage cap is not the hard ceiling it looks like: under Note 49, a site may exceed it by up to half without a variance where drainage is addressed. This is the town's smallest single-family lot standard, at ten thousand square feet on eighty-five feet of width.

• A two-family house answers to a different row: a lot of 0.3444 acres on 100 ft of width, 25 ft to each side and 50 ft for the pair, 50 ft to the rear, and building coverage cut to 20%.
• Uses without their own specified standards follow different figures: 80,000 square feet of lot area on 180 feet of width, 50 ft front, 25 ft each side and 50 ft combined, and 50 ft rear.
• A deck attached to the house without a permanent roof is not treated as a projection into the side or rear yard.
• Height is otherwise expressed as a sky exposure slope measured from the designated street line, but Note 38 overrides that in the residential districts with the flat 35 ft ceiling shown.

Laboratory Office - Height in LO is not a fixed number of feet. It is governed by a slope, a set number of inches of building height for each foot of distance from the designated street line, so a building placed further back can rise higher and no single figure describes the cap.

• No parking is allowed in the required front yard.
• A use that would be permitted in the town's lowest density residence district is held to that district's standards instead of the figures shown here.

Professional Office - Height in PO is not a fixed number of feet. It is set by a sky exposure slope, inches of building height for each foot of distance from the designated street line, so a building set further back may be taller.

• An indoor tennis club or health club is held to a floor area ratio of 0.60 on a lot of not less than three acres.
• Side yards cannot be matched at 25 ft each, since the two together must reach 65 ft, so one side has to be wider.
• No parking is allowed in the required front yard.

Local Shopping - Side yards turn on what adjoins the lot: twenty-five feet where the lot abuts a residential district, and none is required where it abuts a commercial district, though any side yard that is provided must be fifteen feet.

• The front yard may be reduced to the average of the commercial buildings within a hundred feet on each side, on the same side of the street.
• At least ten feet must be kept as buffer.
• Height is governed by a sloping limit measured from the street line rather than a single figure, so a building set back further from the street may be taller.

Community Shopping - Side yards are conditional in CS: none is required where the lot adjoins a commercial district, but any side yard provided must be 15 feet, and 25 feet applies next to a residential district.

• At least 10 feet must be kept as buffer.
• Height is governed by a sloping limit that increases with distance from the designated street line rather than a single figure, so confirm the buildable height with the building department.

Major Regional Shopping - The 30 acre site can be made up of several lots in several ownerships, so long as the land is contiguous apart from the streets and driveways crossing it and the owners declare at site plan that it will be developed as one unified regional shopping centre.

• Where the district adjoins a residential district, yard distances increase by half and a buffer is required along the residential boundary.
• Height is set as a sky exposure slope, in inches of building height for each foot of distance from the designated street line, so no single height figure applies.
• A building set further back from the designated street line may be taller.
• The table sets no minimum lot width.

Light Industrial Office - Height is set by a sky exposure slope, not a fixed number of feet: inches of building height per foot of distance from the designated street line, so a building set further back may be taller. Yard distances increase by half where the district adjoins a residential district.

• An indoor tennis club or health club is held to different standards: a floor area ratio of 0.60 on a lot of not less than three acres.
• No parking is allowed in the required front yard.

Manufacturing - Where this district adjoins a residential district, required yard distances increase by half, and at least 20 feet of the front yard must be kept as a buffer.

• The two side yards must add up to 125 feet, so meeting the 50 foot minimum on each side is not enough; one side has to be wider.
• Height is set by a sky exposure slope, inches of building height for each foot of distance from the designated street line, so a building set further back may be taller.

Commercial Office - Building coverage is not the firm ceiling it looks like: under Note 49, a site may exceed the coverage cap by up to half without a variance where drainage is addressed.

• Where the lot adjoins another CO or COS district, no yard is required, but any yard that is provided must be 15 ft.
• Next to a residential district, the required distance is 30 ft.
• No buffer is required against a CO or COS neighbour.
• The 40 ft height limit is a true ceiling, not a sky exposure slope.

Commercial Office Support - The 70% building coverage cap is not the hard ceiling it looks like. Under note 49, a site may exceed that cap by up to half without a variance where drainage is addressed.

• No yard is required where the lot adjoins another CO or COS district, but any yard that is provided must be 15 feet.
• Where the lot adjoins a residential district, the required distance is 30 feet.
• The 35 foot maximum is a flat height ceiling, not a sky exposure slope.

Multifamily MF-1 - Density depends on bedroom count: the 7.9 units per acre shown is for efficiency units, and one-bedroom units are capped at 6 per acre, two-bedroom at 4.8 and three-or-more-bedroom at 4.

• Land per unit also rises with bedrooms: 5,500 sq ft for an efficiency, 7,250 for one bedroom, 9,000 for two and 10,750 for three or more.
• The 25 ft front setback shown is for a private street; it is fifty feet from a public street and a hundred feet from a state highway.
• The 50 ft side setback drops to 30 ft where a garage, attached or separate, opens into that side yard.
• Height is limited to nine inches of building for each foot of distance from the lot line, up to 3 storeys or 35 ft.
• No two principal buildings may stand closer to each other than the height of the taller one.

Multifamily MF-2 - Density depends on bedroom count: the 13 units per acre shown is for efficiency units, and one-bedroom units are capped at 11.5 per acre, two-bedroom at 10 and three-or-more-bedroom at 9.1.

• Land per unit also rises with bedrooms: 3,350 sq ft for an efficiency, 3,800 for one bedroom, 4,300 for two and 4,800 for three or more.
• The 25 ft front setback shown is for a private street; it is fifty feet from a public street and a hundred feet from a state highway.
• The 50 ft side setback drops to 30 ft where a garage, attached or separate, opens into that side yard.
• Height is limited to nine inches of building for each foot of distance from the lot line, up to 3 storeys or 35 ft.
• No two principal buildings may stand closer to each other than the height of the taller one.

Multifamily MF-3 - Density depends on bedroom count: the 18.1 units per acre shown is for efficiency units, and one-bedroom units are capped at 15.6 per acre, two-bedroom at 13.6 and three-or-more-bedroom at 12.1.

• Land per unit also rises with bedrooms: 2,400 sq ft for an efficiency, 2,800 for one bedroom, 3,200 for two and 3,600 for three or more.
• The 25 ft front setback shown is for a private street; it is fifty feet from a public street and a hundred feet from a state highway.
• The 50 ft side setback drops to 30 ft where a garage, attached or separate, opens into that side yard.
• Height is limited to nine inches of building for each foot of distance from the lot line, up to 3 storeys or 35 ft.
• No two principal buildings may stand closer to each other than the height of the taller one.

Active Adult Residence - This district floats, applied over an existing district rather than mapped on its own. The yards are not fixed figures: front, side and rear must each be at least as deep as the building is tall, so a taller building sits further from every line.

• Height runs 35 feet over the multifamily, general residence, R-10, R-15 and R-22 districts and 45 feet over LO, PO, LS, CS and LIO, except in a Hamlet Center area, where 35 feet governs.
• The two side yards together must be at least the sum of the front and side setbacks.
• The 3 acre minimum is measured as net lot area, and the 300 foot dimension is a minimum front lot line for the overall site.
• The site must have access to a state or county major or secondary road on the Town Official Map.
• A 20 foot landscaped buffer runs along every lot line.
• No dwelling unit may have more than three bedrooms, and no single building may hold more than 50 units.

Neighborhood Shopping - The 15 ft front yard is a band, not a floor: the maximum front setback is 45 ft, so a building set too far back breaks the rule just as one set too far forward does. Side and rear yards rise to 25 ft where the parcel borders a residential district.

• A mixed-use building gets three storeys and 35 ft of height on a lot of 0.4591 acres, with density by bedroom count: 11.3 units to the acre for one-bedroom units and 10.0 for two-bedroom.
• Senior housing by special permit takes 1 acre at 20 units to the acre, three storeys at 35 ft, 33% building and 66% total coverage, and excludes a superintendent's apartment of up to three bedrooms.
• At least 5 ft of each side and rear yard must be a landscaped buffer, and 10 ft where the development abuts a residential district or is senior housing.
• Floor area ratio rises from 0.50 to 0.60, by stormwater runoff cuts of 5, 10 or 20 percent giving 0.525, 0.55 and 0.60, or by LEED certification giving 0.55, 0.575 and 0.60. Only one route counts.
• The two coverage caps measure different things: 30 percent applies to principal buildings and 60 percent to everything on the lot together.
• Parking has to go behind or beside the principal building.