What it costs to build an ADU in Irvington, NY

One-Family Residence District - A dwelling built without a garage must add 12 ft to one side yard (§ 224-11B(3)).

• All principal and accessory buildings together may cover 16% of the first 20,000 sq ft of the lot plus 6% of the area above that, and driveways are not counted (§ 224-13A).
• In a cluster subdivision a detached one-family lot may drop to 0.2296 acre, 85 ft wide and 100 ft deep, with front and rear yards of 30 ft, and the cluster keeps a 30 ft buffer (§ 224-88D(2)(a)).
• No building, wall or parking space may stand within 50 ft of the Broadway right of way, or 30 ft of the Croton Aqueduct property, and 125 ft and 50 ft respectively on a new or rebuilt lot (§ 224-51).
• On a vacant lot the dwelling count is the net buildable area divided by 20,000 sq ft, after taking out watercourses, wetland and floodplain and part of any land on slopes of 15% or more (§ 224-80).
• Floor area for a house follows a villagewide scale keyed to lot size, 0.20 at 20,000 sq ft, and any house over 10,000 sq ft of gross floor area needs a variance (§ 224-136).
• Front and side yard minimums may be reduced by 20% where a building's walls meet the street or side line at an angle of 25° or more.

One-Family Residence District - A dwelling built without a garage must add 12 ft to one side yard (§ 224-11B(3)).

• All principal and accessory buildings together may cover 12% of the first 40,000 sq ft of the lot plus 4% of the area above that, and driveways are not counted (§ 224-13).
• In a cluster subdivision a detached one-family lot may drop to 0.4591 acre, 100 ft wide and 125 ft deep, with a side yard of 15 ft and front and rear yards of 35 ft (§ 224-88D(2)(a)).
• No building, wall or parking space may stand within 50 ft of the Broadway right of way, or 30 ft of the Croton Aqueduct property, and 125 ft and 50 ft respectively on a new or rebuilt lot (§ 224-51).
• On a vacant lot the dwelling count is the net buildable area divided by 40,000 sq ft, after taking out watercourses, wetland and floodplain and part of any land on slopes of 15% or more (§ 224-80).
• Floor area for a house follows a villagewide scale keyed to lot size, 0.1625 at 40,000 sq ft, and any house over 10,000 sq ft of gross floor area needs a variance (§ 224-136).
• Front and side yard minimums may be reduced by 20% where a building's walls meet the street or side line at an angle of 25° or more.

One-Family Residence District - Front and side yard minimums may be reduced by 20% where a building's walls meet the street or side line at an angle of 25° or more (§ 224-11B(1)).

• All principal and accessory buildings together may cover 8.33% of the first 60,000 sq ft of the lot plus 2% of the area above that, and driveways are not counted (§ 224-13).
• In a cluster subdivision a detached one-family lot may drop to 0.6887 acre, 150 ft wide and 150 ft deep, with a side yard of 20 ft and front and rear yards of 50 ft (§ 224-88D(2)(a)).
• No building, wall or parking space may stand within 50 ft of the Broadway right of way, or 30 ft of the Croton Aqueduct property, and 125 ft and 50 ft respectively on a new or rebuilt lot (§ 224-51).
• On a vacant lot the dwelling count is the net buildable area divided by 60,000 sq ft, after taking out watercourses, wetland and floodplain and part of any land on slopes of 15% or more (§ 224-80).
• Floor area for a house follows a villagewide scale keyed to lot size, 0.125 at 60,000 sq ft and above, and any house over 10,000 sq ft of gross floor area needs a variance (§ 224-136).
• The minimum lot depth may be reduced by 15% where the lot's average depth still meets the minimum (§ 224-10C).

One-Family Residence District - Front and side yard minimums may be reduced by 20% where a building's walls meet the street or side line at an angle of 25° or more (§ 224-11B(1)).

• All principal and accessory buildings together may cover 6.75% of the first 80,000 sq ft of the lot plus 2% of the area above that, and driveways are not counted (§ 224-13).
• In a cluster subdivision a detached one-family lot may drop to 0.9183 acre, 200 ft wide and 150 ft deep, with a side yard of 30 ft and front and rear yards of 50 ft (§ 224-88D(2)(a)).
• No building, wall or parking space may stand within 50 ft of the Broadway right of way, or 30 ft of the Croton Aqueduct property, and 125 ft and 50 ft respectively on a new or rebuilt lot (§ 224-51).
• On a vacant lot the dwelling count is the net buildable area divided by 80,000 sq ft, after taking out watercourses, wetland and floodplain and part of any land on slopes of 15% or more (§ 224-80).
• Floor area for a house follows a villagewide scale keyed to lot size, 0.125 at 60,000 sq ft and above, and any house over 10,000 sq ft of gross floor area needs a variance (§ 224-136).
• The minimum lot depth may be reduced by 15% where the lot's average depth still meets the minimum (§ 224-10C).

One-Family Residence District - A dwelling built without a garage must add 12 ft to one side yard (§ 224-11B(3)).

• All principal and accessory buildings together may cover 20% of the first 10,000 sq ft of the lot plus 12% of the area above that, and driveways are not counted (§ 224-13A).
• In a cluster subdivision a detached one-family lot may drop to 0.1722 acre, 60 ft wide and 100 ft deep, with a side yard of 10 ft and front and rear yards of 30 ft (§ 224-88D(2)(a)).
• No building, wall or parking space may stand within 50 ft of the Broadway right of way, or 30 ft of the Croton Aqueduct property, and 125 ft and 50 ft respectively on a new or rebuilt lot (§ 224-51).
• On a vacant lot the dwelling count is the net buildable area divided by 10,000 sq ft, after taking out watercourses, wetland and floodplain and part of any land on slopes of 15% or more (§ 224-80).
• Research and development laboratories and several kinds of office use are open by special permit on a lot fronting Broadway (§ 224-8D(4)).
• Front and side yard minimums may be reduced by 20% where a building's walls meet the street or side line at an angle of 25° or more.

One-Family Residence District - Front and side yard minimums may be reduced by 20% where a building's walls meet the street or side line at an angle of 25° or more (§ 224-11B(1)).

• All principal and accessory buildings together may cover 24% of the first 5,000 sq ft of the lot plus 16% of the area above that, and driveways are not counted (§ 224-13A).
• In a cluster subdivision a detached one-family lot may drop to 0.0918 acre, 40 ft wide and 100 ft deep, with a side yard of 5 ft and front and rear yards of 30 ft (§ 224-88D(2)(a)).
• No building, wall or parking space may stand within 50 ft of the Broadway right of way, or 30 ft of the Croton Aqueduct property, and 125 ft and 50 ft respectively on a new or rebuilt lot (§ 224-51).
• On a vacant lot the dwelling count is the net buildable area divided by 5,000 sq ft, after taking out watercourses, wetland and floodplain and part of any land on slopes of 15% or more (§ 224-80).
• Only one parking space per dwelling is required here, and it may sit in a side yard (§ 224-14).
• The minimum lot depth may be reduced by 15% where the lot's average depth still meets the minimum (§ 224-10C).

Two-Family Residence District - 2F is held to every requirement of the 1F-5 district (§ 224-16).

• On a vacant lot a two-family house needs 10,000 sq ft of net buildable land even though the lot minimum is 5,000 sq ft (§ 224-80).
• A two-family dwelling is permitted provided the whole lot stays in one ownership for the life of the building (§ 224-15B).
• Building coverage follows the 1F-5 rule, 24% of the first 5,000 sq ft of the lot plus 16% of the area above that, with driveways not counted (§ 224-13).
• A fair and affordable two-family unit may sit on a lot of 75% of the two-family minimum (§ 224-179B).

Multifamily Residence District - A three-or-more-family dwelling is permitted only on a lot fronting Broadway or the New York Central Railroad right of way, and the whole lot must stay in one ownership for the life of the building (§ 224-17C).

• A one-family or two-family house here takes the 1F-10 standards, a lot 85 ft wide and 100 ft deep with a 15 ft side yard and 30 ft front and rear yards (§ 224-19A).
• Building coverage for a house follows the 1F-10 rule, 20% of the first 10,000 sq ft of the lot plus 12% of the area above that (§ 224-20A).
• An attached one-family development may cover 18% of the lot, and coverage from reusing a locally significant historic building is left out of the count, though total may never exceed 20% (§ 224-20D).
• A use needing a Planning Board special permit is open only on a lot fronting Broadway or the railroad right of way, may cover 15% of the lot and owes 100 ft side and rear yards (§ 224-20C).
• Buildings stand at least 60 ft apart, no building runs longer than 180 ft, and no building holds more than 15 dwelling units (§ 224-21).
• Building coverage is 10% of the lot, and the Planning Board may allow another 5% for accessory garages where parking under the principal building is impractical (§ 224-20B).

Business District - No yard is required in B unless the Planning Board requires one, but a lot adjoining a residence district boundary needs a 10 ft yard on that side (§ 224-37).

• Any yard that is required or provided must be at least 4 ft wide.
• Dwelling units are allowed only on the second and higher floors, above ground floor retail or service space (§ 224-36A(15)(b)).
• A building on Main Street may rise no higher than the average height of the existing structures on the two neighbouring lots, measured from the lowest street level (§ 224-38A).
• On a lot carrying dwelling units an existing building may cover 70% of the lot, and buildings, parking and driveways together 80%; on new construction only the 80% total applies (§ 224-36A(15)(c)).
• A building abutting a public parking lot must keep unobstructed space on its own lot for loading two vehicles, each at least 10 ft by 30 ft (§ 224-52).

Railroad District - Yards are required only if the Planning Board imposes one, and any such yard must be at least 4 ft wide (§ 224-46B(4)).

• A Planning Board special permit for land on the east side of the tracks between Main and Bridge Streets opens a wider set of uses, with front, side and rear yards of 0 ft (§ 224-46B(4)).
• Under that permit principal buildings may cover 14% of the lot, accessory buildings another 10%, and buildings with parking and driveways together 80% (§ 224-46B(5)).
• The chapter states no lot area and no lot width for this district (§ 224-47).
• A change of occupancy or use here needs Planning Board approval (§ 224-54.1).

Recreation District - A building must stand at least 50 ft from any street line, and from every other property line at least the greater of 50 ft or three times its height (§ 224-47.4).

• A buffer of at least 40 ft runs around the whole perimeter, and no structure, pool, green, fairway or tee may sit in it (§ 224-47.3C).
• The 200 ft is both the minimum lot width and the minimum length of street line frontage (§ 224-47.3B).
• Principal and accessory uses are barred from the required front yard (§ 224-47.4).
• All principal and accessory buildings together may cover 3.5% of the lot, with driveways not counted (§ 224-47.5).
• A public playground or park, including a golf, tennis or swimming club, is available on a Planning Board special permit that requires a traffic study (§ 224-47.2B).

Multifamily/Office District - Every use in this district needs a Planning Board special permit, and nothing may be built, parked or placed within 250 ft of the Broadway right of way unless the Board of Trustees waives that distance for a significant public interest (§ 224-47.9B(2)).

• The side and rear yards rise to 75 ft where the lot abuts a one-family district, and two properties do not abut if a street runs between them (§ 224-47.9B(1)).
• Between 250 and 300 ft of Broadway nothing may exceed two stories or 25 ft, and beyond 300 ft the limit is three stories or 35 ft, with underground parking not counted as a storey (§ 224-47.9E).
• No new lot may be created with less than 80,000 sq ft (§ 224-47.9A).
• Coverage is measured against the net buildable site area rather than the gross lot, and where the floor area limit and the coverage limit disagree the smaller building controls (§ 224-47.9G).
• On a special permit for senior citizen housing each unit counts 2,000 sq ft of land instead of 3,000, and it does not qualify for the density bonuses (§ 224-85.1).
• A development providing the full number of moderate-income units earns 5% more coverage and 0.05 more floor area (§ 224-47.9D(4)).

Waterfront District - No yard is required, but any yard provided must be at least 4 ft wide, and where the lot adjoins a residence district boundary a yard of at least 10 ft is required along that boundary (§ 224-41).

• Multifamily dwellings are available in buildings on the east side of the Railroad District on a Board of Trustees special permit, which asks 1,250 sq ft of land for each dwelling unit (§ 224-39F(2)).
• Under that permit an existing building owes one side yard of at least 100 ft, no building may run longer than 180 ft or hold more than 25 dwelling units, and buildings may cover 40% of the lot.
• Floor area may not exceed 1.4 times the dry land area of the lot, measured from the bulkhead or the mean high water line (§ 224-40).
• Cellar and basement space used only for storage or building operation is left out of the floor area count (§ 224-40).
• Adaptive reuse of a building on the National Register or designated a local landmark is available on a Board of Trustees special permit (§ 224-39F(1)).
• A change of occupancy or use here needs Planning Board approval (§ 224-54.1).