Can you build an ADU in Cornwall, NY?

Mountain Conservation Residential - The figures shown are those for a house, and the two side yards must add to a hundred and fifty feet, so one side must carry a hundred. Uses that need a special permit have their own standards.

• Road frontage must be at least 200 feet, a standard separate from lot width.
• Building coverage counts the footprint alone; the total coverage figure is development coverage, which counts drives, parking and every other developed surface with it.
• The floor area ratio of 0.05 binds long before the building coverage cap does.
• Churches and similar places of worship, a special permit use, take a hundred and sixty thousand square feet on five hundred feet of width at seventy percent development coverage.
• Essential services and wind turbines, also special permit uses, are left to whatever their special permit specifies.
• A bed-and-breakfast residence takes the same row as a house.

Agricultural Rural Residential - Road frontage of at least 200 feet applies on top of the lot width. The total coverage figure is development coverage, which counts drives, parking and every other developed surface along with the building footprint.

• The figures shown are one use group's; other uses have their own standards by use group, and one group's standards are set by its special permit.

Suburban Low-Density Residential - Converting a single-family house to a two-family dwelling is a special permit use here and takes at least a hundred and sixty thousand square feet, not the two-acre minimum shown.

• Churches, cemeteries and family and group care facilities, also special permit uses, take the same hundred and sixty thousand square feet, on five hundred feet of width.
• Private schools, a special permit use, take twenty acres on nine hundred feet of lot width, at fifty feet of height and thirty percent development coverage.
• Day-care centers, nursery schools and a bed-and-breakfast residence take sixty thousand square feet on two hundred feet of width.
• Essential services and wind turbines are left to whatever their special permit specifies, and a home professional office takes the residential requirements of the structure.
• Road frontage must be at least 150 feet, a standard separate from lot width.
• Building coverage counts the footprint alone; the total coverage figure is development coverage, which counts drives, parking and every other developed surface with it.

Medium Residential - MR also admits multiple dwelling developments and two-family, townhouse and clustered development under § 278 of the Town Law, with their own standards. One group needs at least twenty acres on at least two hundred feet of width and at least seven hundred sq ft of liveable area.

• Another of these groups needs at least twenty acres, with its other standards left to the special permit.
• Road frontage of at least 150 feet applies on top of the lot width.
• The total coverage figure is development coverage, which counts drives, parking and every other developed surface along with the building footprint.

Suburban Residential 1 - The figures shown are for a house reached only by a driveway, with no public water and no public sewer. With one of the two services the lot must be at least thirty thousand square feet, and with both at least twenty thousand.

• A two-family house is permitted only with both public water and public sewer, on at least thirty thousand square feet.
• Mobile home development needs at least thirty acres, thirty thousand square feet of land for every unit and a thousand feet of lot width, with a twenty-five-foot height limit.
• Road frontage of at least 100 feet applies on top of the lot width.
• The total coverage figure is development coverage, which counts drives, parking and every other developed surface along with the building footprint.

Suburban Residential 2 - The figures shown are for a one-family detached dwelling with house service to public water and sewer systems.

• A two-family house needs at least thirty thousand square feet and the same public water and sewer service.
• Road frontage of at least 70 feet applies on top of the lot width.
• The total coverage figure is development coverage, which counts drives, parking and every other developed surface along with the building footprint.

Limited Service - The whole lot may be developed, with half of it in buildings, and no side yard or rear yard is required. Uses that need a special permit are held to their own lot, yard and coverage standards instead.

• A filling station or a bed-and-breakfast, by special permit, takes twenty thousand square feet on two hundred feet of width, at twenty-five feet of height and ten percent building coverage.
• A filling station or bed-and-breakfast also needs fifty-foot side yards, a hundred feet for the pair, and a twenty-foot rear yard.
• A social hall for a fraternal organization, health clubs and a day-care center, by special permit, take forty thousand square feet on two hundred feet at forty percent and a floor area ratio of 0.7.
• Churches and similar places of worship, by special permit, take a hundred and sixty thousand square feet on five hundred feet at a floor area ratio of 1.15.
• Road frontage must be at least 50 feet, a standard separate from lot width.

General Commercial - No side or rear yard is required, and the whole lot is available for development.

• Road frontage of at least 50 feet applies on top of the lot width.
• Development coverage counts drives, parking and every other developed surface along with the building footprint.
• Other uses fall in use groups with their own standards; one allows sixty feet of height and a floor area ratio of 1.40.

Highway Commercial - Road frontage of at least 100 feet applies on top of the lot width. The total coverage figure is development coverage, which counts drives, parking and every other developed surface along with the building footprint.

• The figures shown are one use group's; other uses have their own standards, one held to fifteen percent building coverage and a floor area ratio of 0.15.

Planned Commercial Development, Planned Industrial/Office - Lot area, width, yards, height and coverage here are set case by case in the special permit when it is granted, rather than in advance. Ask the Planning Board what a specific proposal would be held to.