Can you build an ADU in Ossining, NY?

One-Family Residence, One-Family Residence, One-Family Residence, One-Family Residence, One-Family Residence - The maximum floor area of a one-family residence is 5,000 sq ft plus 0.052521 of the lot area above 43,560 sq ft, § 200-21C. Impervious surface is capped separately, on a sliding scale that grows with lot area.

• Lots may also be laid out as a cluster development, which for detached houses follows the R-5 standards and needs Planning Board subdivision and site plan approval.
• On a street with a right-of-way narrower than 50 feet the front yard is measured from the street center line, with 25 feet added.
• A lot held separately in ownership when the chapter took effect may be built on for a one-family residence without meeting the lot area, lot width and side yard minimums.
• A residential density bonus of 20% on 10 acres or more, 30% above 5 acres and 40% on 5 acres or less is granted where half the bonus units are below market rate.
• An accessory building up to 15 feet high may stand in a required side or rear yard if it is set back 10 feet from every lot line and all such buildings cover no more than 30% of that required yard.
• Creating more than 100 sq ft of impervious surface needs a permit from the Building Inspector.

One-Family Residence, One-Family Residence - The maximum floor area of a one-family residence is 5,000 sq ft plus 0.052521 of the lot area above 43,560 sq ft, § 200-21C. Impervious surface is capped separately, on a sliding scale that grows with lot area.

• Converting an existing residential structure to a two-family dwelling needs a special permit from the Board of Appeals, a lot of at least 10,000 sq ft and 750 sq ft of living floor area in each unit.
• Lots may also be laid out as a cluster development, which for detached houses follows the R-5 standards and needs Planning Board subdivision and site plan approval.
• On a street with a right-of-way narrower than 50 feet the front yard is measured from the street center line, with 25 feet added.
• A lot held separately in ownership when the chapter took effect may be built on for a one-family residence without meeting the lot area, lot width and side yard minimums.
• A residential density bonus of 20% on 10 acres or more, 30% above 5 acres and 40% on 5 acres or less is granted where half the bonus units are below market rate.
• An accessory building up to 15 feet high may stand in a required side or rear yard if it is set back 10 feet from every lot line and all such buildings cover no more than 30% of that required yard.

One-Family Residence - The maximum floor area of a one-family residence is 5,000 sq ft plus 0.052521 of the lot area above 43,560 sq ft, § 200-21C. Impervious surface is capped separately, on a sliding scale that grows with lot area.

• Converting an existing residential structure to a two-family dwelling needs a special permit from the Board of Appeals, a lot of at least 10,000 sq ft and 750 sq ft of living floor area in each unit.
• On a street with a right-of-way narrower than 50 feet the front yard is measured from the street center line, with 25 feet added.
• A lot held separately in ownership when the chapter took effect may be built on for a one-family residence without meeting the lot area, lot width and side yard minimums.
• A residential density bonus of 20% on 10 acres or more, 30% above 5 acres and 40% on 5 acres or less is granted where half the bonus units are below market rate.
• An accessory building up to 15 feet high may stand in a required side or rear yard if it is set back 10 feet from every lot line and all such buildings cover no more than 30% of that required yard.
• Creating more than 100 sq ft of impervious surface needs a permit from the Building Inspector.

One-Family Residence - The code sets no lot, width, depth, yard, height or coverage standard under the R-80 name. The Building Department can say which current district a parcel here carries.

Multifamily - The figures shown are for row and attached dwellings, which need at least 4,000 sq ft of lot per unit plus 1,500 sq ft per bedroom. A multiple dwelling needs a front yard of at least 50 ft on a lot at least 100 ft wide and 150 ft deep.

• The 50 ft one-side and 100 ft combined side yards apply only between buildings and side lot lines.
• Livable floor area per unit is 450 sq ft for a studio or efficiency, 675 for one bedroom, 750 for two, 1,000 for three and 1,200 for four.
• At least 1/3 of the net site area must be permanent open space or recreation, with 1,500 sq ft of undeveloped open space per bedroom and a 400 sq ft play area for each dwelling unit.
• No building may exceed 150 feet in length, principal buildings must stand twice the height of the taller apart, and a principal and an accessory building 20 feet apart.
• A group of row dwellings may hold no more than six units.
• A residential density bonus of 20% on 10 acres or more, 30% above 5 acres and 40% on 5 acres or less is granted where half the bonus units are below market rate.

Office-Research Manufacturing - The district list in the code names no Office-Research Manufacturing district, and the figures shown are the ones § 200-24 publishes for the Office-Research Business district. Every use is subject to site plan approval.

• Side and rear yards are 200 feet on a lot along a residence district boundary, including one in another municipality.
• A parcel of 10 acres or more may be subdivided, and each principal building then needs a lot of at least two acres, with side and rear yards of 50 feet.
• Each lot in such a subdivision needs 200 feet of street frontage, which the Planning Board may reduce to 100 feet on a cul-de-sac or a curve.
• Parking and loading must stand at least 200 feet from a residence district boundary and 100 feet from any other lot line.
• In a parking lot of an acre or more at least 5% of the lot must be interior landscaping.
• Buildings must stand at least as far apart as the taller one is high and never less than 30 feet.

General Business - Multiple dwellings and row or attached dwellings are allowed on a lot of at least 20,000 sq ft under the multifamily standards of § 200-22. No side or rear yard is required here, but each is at least 30 feet on a lot along a residence district boundary.

• A multiple dwelling needs a front yard of at least 50 feet, a lot at least 100 feet wide and 150 feet deep, side yards of at least 50 feet and 100 feet combined, with coverage capped at 20%.
• A row or attached dwelling needs a front yard of at least 25 feet, side yards of at least 50 feet and 100 feet combined and a rear yard of at least 40 feet, with coverage capped at 20%.
• For those dwellings the Planning Board may modify the lot width, lot depth, yard, usable open space and building coverage requirements of § 200-22.
• Dwelling unit sizes are 450 sq ft for a studio or efficiency, 675 for one bedroom, 750 for two, 1,000 for three and 1,200 for four, and no dwelling unit may be in a basement or cellar.
• A residential density bonus of 20% on 10 acres or more, 30% above 5 acres, 40% above 2 acres and 100% below 2 acres is granted where half the bonus units are below market rate.
• No side or rear yard is required where that yard abuts an operating railroad right-of-way.

General Business-1 - The Planning Board may increase the required front, side and rear setbacks by up to a factor of two, or reduce or eliminate them, on site plan review. No side or rear yard is required, but each is at least 30 feet on a lot along a residence district boundary.

• That change rests on the Planning Board's findings about topography, slopes, grades, sight distances and highway conditions, and a finding of no adverse impact on abutting properties.
• Every use in the district is subject to site plan approval.
• There is no outdoor storage of any kind and no outdoor parking of construction equipment.
• No side or rear yard is required where that yard abuts an operating railroad right-of-way.
• Where § 200-18.1 conflicts with another section of the chapter, § 200-18.1 controls.

Neighborhood Commercial - Aggregate floor area on any lot is capped at 12,000 sq ft, and on a lot along a residence district boundary the side and rear yards must each be at least 30 ft.

• A one-family dwelling is regulated as in the R-5 district and a two-family dwelling by the R-10 figures.
• Multiple and row or attached dwellings need a lot of at least 15,000 sq ft with 5,000 sq ft of lot area per unit, and no group of row dwellings may hold more than six units.
• A mixed use needs a lot of at least 20,000 sq ft, one dwelling unit per 10,000 sq ft of lot area and no more than 4,800 sq ft of nonresidential floor area per acre.
• Artist live and work spaces are allowed at one per 5,000 sq ft of lot area, each at least 800 sq ft with no more than 30% of its floor area residential.
• A buffer at least 20 feet wide with native landscape screening is required between a nonresidential use and a residentially used or zoned lot.
• Principal buildings must stand twice the height of the taller apart, and a principal and an accessory building 20 feet apart.

Business Education - On a lot along a residence district boundary, in this town or another municipality, the side and rear yards must each be at least 150 ft.

• The subdivision option that reaches the Office-Research Business and Office-Research Education districts does not reach this one, so the 40 acre minimum is not reduced.
• The height may rise to 50 feet where a substantial part of the added height houses ventilators, water tanks, bulkheads and similar rooftop features in harmony with the building.
• Other rooftop features may rise above the limit if they cover no more than 20% of the roof and stand no more than 15 feet above it.
• Parking and loading must stand at least 100 feet from a residence district boundary and 30 feet from any other lot line.
• In a parking lot of an acre or more at least 5% of the lot must be interior landscaping.
• The amount of off-street parking and loading is set by the Planning Board on site plan approval.

Multifamily-Inn - Lot area per dwelling unit is 4,000 sq ft plus 1,500 sq ft for each bedroom, on a lot of at least 20,000 sq ft. The 50 foot single and 100 foot combined side yards apply only between buildings and side lot lines.

• A row or attached dwelling needs 20 feet of lot width, 100 feet of lot depth and a 25 foot front yard.
• Every use the R-40 district permits is also permitted here and regulated as in R-40, so a one-family house needs a 150 foot lot width, a 40 foot front yard and 20 foot side yards.
• An inn or a bed-and-breakfast establishment, with accessory shops, eating and drinking establishments, recreation facilities and spas, is a conditional use needing Planning Board approval.
• A bed-and-breakfast establishment may hold no more than eight guest bedrooms and needs a lot of at least 20,000 sq ft for two guest bedrooms, 30,000 for three and 40,000 for four.
• It must be owner occupied, must look like a one-family dwelling from outside, and no guest may stay longer than two weeks.
• At least 1/3 of the net site area must be permanent open space or recreation, with 1,500 sq ft of undeveloped open space per bedroom and a 400 sq ft play area for each dwelling unit.

Office-Research Education - One-family dwellings and every use the R-20 district permits are allowed here, and the code states no separate lot, yard or coverage standard for them. Side and rear yards are 200 feet on a lot along a residence district boundary in any municipality.

• A parcel of 10 acres or more may be subdivided, and each principal building then needs a lot of at least two acres, with side and rear yards of 50 feet.
• Each lot in such a subdivision needs 200 feet of street frontage, which the Planning Board may reduce to 100 feet on a cul-de-sac or a curve.
• Parking and loading must stand at least 100 feet from a residence district boundary and 30 feet from any other lot line, and the amount of parking is set by the Planning Board on site plan approval.
• In a parking lot of an acre or more at least 5% of the lot must be interior landscaping.
• Buildings must stand at least as far apart as the taller one is high and never less than 30 feet.
• Rooftop ventilators, water tanks, bulkheads and chimneys may rise above the height limit if they cover no more than 20% of the roof and stand no more than 15 feet above it.