What it costs to build an ADU in Rye Brook, NY

One-Family Residential District - The 45 ft front yard is a floor: where the lots on both sides have deeper existing front yards, the required front yard is the average of those two. A lot must also fit a 125 ft horizontal circle (§ 250-18.2).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-18.2F).
• A height to setback ratio also caps the building, 0.48 at the front and 1.30 at the side, each an inclined plane rising from average grade at the lot line (§ 250-18.2J).
• Side yards are stated twice, 15 ft for the narrower yard and 40 ft for the two together, so meeting the single figure on both sides is not enough.
• The 14% is main building coverage; § 250-37B allows another 3.5% for accessory buildings and 4% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 20% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-18.2K).

One-Family Residential District - The frontage figure is the required street frontage, and the lot must also hold a circle 75 ft across with a building site inside it (§ 250-22F).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-22E).
• A height to setback ratio also caps the building, 0.80 at the front and 2.40 at the side, each an inclined plane rising from average grade at the lot line (§ 250-22I).
• Side yards are stated twice, 10 ft for the narrower yard and 25 ft for the two together, so meeting the single figure on both sides is not enough.
• The 20% is main building coverage; § 250-37B allows another 4.5% for accessory buildings and 3.5% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 45% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-22J).

One-Family Residential District - The frontage figure is the required street frontage, and the lot must also hold a circle 100 ft across with a building site inside it (§ 250-21F).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-21E).
• A height to setback ratio also caps the building, 0.69 at the front and 1.60 at the side, each an inclined plane rising from average grade at the lot line (§ 250-21I).
• Side yards are stated twice, 15 ft for the narrower yard and 40 ft for the two together, so meeting the single figure on both sides is not enough.
• The 17% is main building coverage; § 250-37B allows another 4% for accessory buildings and 4% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 40% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-21J).

One-Family Residential District - The frontage figure is the required street frontage, and the lot must also hold a circle 100 ft across with a building site inside it (§ 250-20F).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-20E).
• A height to setback ratio also caps the building, 0.60 at the front and 1.60 at the side, each an inclined plane rising from average grade at the lot line (§ 250-20I).
• Side yards are stated twice, 15 ft for the narrower yard and 40 ft for the two together, so meeting the single figure on both sides is not enough.
• The 16% is main building coverage; § 250-37B allows another 3.5% for accessory buildings and 4% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 35% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-20J).

One-Family Residential District - The frontage figure is the required street frontage, and the lot must also hold a circle 100 ft across with a building site inside it (§ 250-20.1F).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-20.1E).
• A height to setback ratio also caps the building, 0.80 at the front and 2.40 at the side, each an inclined plane rising from average grade at the lot line (§ 250-20.1I).
• Side yards are stated twice, 10 ft for the narrower yard and 20 ft for the two together, so meeting the single figure on both sides is not enough.
• The 12% is main building coverage; § 250-37B allows another 3.5% for accessory buildings and 4% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 35% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-20.1J).

One-Family Residential District - The 40 ft front yard is a floor: where the lots on both sides have deeper existing front yards, the required front yard becomes the average of those two. A lot must also fit a 125 ft horizontal circle (§ 250-19).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-19F).
• A height to setback ratio also caps the building, 0.60 at the front and 1.60 at the side, each an inclined plane rising from average grade at the lot line (§ 250-19J).
• Side yards are stated twice, 15 ft for the narrower yard and 40 ft for the two together, so meeting the single figure on both sides is not enough.
• The 14% is main building coverage; § 250-37B allows another 3.5% for accessory buildings and 4% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 30% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-19K).

One-Family Residential District - The frontage figure is the required street frontage, and the lot must also hold a circle 50 ft across with a building site inside it (§ 250-24F).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-24E).
• A height to setback ratio also caps the building, 1.20 at the front and 4 at the side, each an inclined plane rising from average grade at the lot line (§ 250-24I).
• Side yards are stated twice, 6 ft for the narrower yard and 16 ft for the two together, so meeting the single figure on both sides is not enough.
• The 30% is main building coverage; § 250-37B allows another 5% for accessory buildings and 3.5% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 30% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-24J).

One-Family Residential District - The frontage figure is the required street frontage, and the lot must also hold a circle 60 ft across with a building site inside it (§ 250-23F).

• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-23E).
• A height to setback ratio also caps the building, 0.96 at the front and 3 at the side, each an inclined plane rising from average grade at the lot line (§ 250-23I).
• Side yards are stated twice, 8 ft for the narrower yard and 20 ft for the two together, so meeting the single figure on both sides is not enough.
• The 23% is main building coverage; § 250-37B allows another 4.5% for accessory buildings and 3.5% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 40% (§ 250-37C, § 250-37D).
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-23J).

Two-Family Residential District - An existing dwelling may be converted for more than one family under conditions that include floor space per unit and off-street parking (§ 250-25).

• Only a dwelling existing on 7-24-1984 may be converted, and it needs 750 sq ft of floor space per family outside basement and attic, an unchanged exterior and the required parking (§ 250-25M(2)).
• The frontage figure is the required street frontage, and the lot must also hold a circle 50 ft across with a building site inside it (§ 250-25F).
• Side yards are stated twice, 6 ft for the narrower yard and 16 ft for the two together.
• The 30% is main building coverage; § 250-37B allows another 5% for accessory buildings and 3.5% for decks, and counts porches toward lot area coverage.
• Each dwelling unit needs 1,200 sq ft of usable open space (§ 250-25J).
• The schedule sets no minimum dwelling floor area in this district (§ 250-25L).

Restricted Multifamily District - Buildings in a group must be at least 100 ft apart, except that two windowless end walls facing each other may come within 35 ft (§ 250-26L(2)).

• The lot minimum is stated as two standards at once: 10 acres for the site, and 2,000 sq ft of land for every family housed on it (§ 250-26F(1)).
• The frontage figure is the required street frontage, and the lot must also hold a circle 500 ft across with a building site inside it (§ 250-26F).
• Usable open space of at least 200 sq ft per unit is required.
• The district also takes every use permitted in the R2-F District as permitted there, and a conversion of an existing building for more than one family follows the R2-F rule (§ 250-26A(1)).
• A development of 10 or more dwelling units, or of more than one building, needs site plan approval (§ 250-26L(3)).
• The schedule publishes no floor area ratio and no minimum dwelling floor area here, and no building coverage cap (§ 250-26E, § 250-26K).

Campus/Office Building District - On a site of 30 acres or more the front setback rises to at least 200 ft from street lines, and parking must be set back at least 100 ft from street and side lines. On a smaller site, parking must be set back at least 75 ft from street and side lines.

• The Planning Board may approve a smaller parking setback between adjoining office developments on site plan review (§ 250-27).

Office Building District - An office or professional building, or a research and testing laboratory, needs a lot of at least 5 acres that holds a circle 275 feet across (§ 250-28E).

• The district also permits every use of the R-10 District, and the lot standard above does not reach those uses (§ 250-28A(1)).

Office Building and Business District - Height is limited to 1 story, but may rise to 3 stories and 45 ft where lot coverage is held to no more than 15%, with the third story no more than 25% of the ground-floor area (§ 250-30).

Neighborhood Retail District - Side yard, height and usable open space are set equal to the C1-P district’s own figures (§ 250-32).

• No side yard is required, but one that is provided must be at least 4 ft, and 6 ft where the lot adjoins a residence district line (§ 250-32G(2)).
• On a corner lot within 50 ft of a residence district line the building takes half that district’s required front yard as a side yard (§ 250-32G(2)).
• Fireproof or semifireproof construction may reach three stories and 40 ft (§ 250-32).
• The frontage figure is the required street frontage, and the lot must also hold a circle 90 ft across with a building site inside it (§ 250-32F).
• A gasoline station needs a special permit from the Village Board, and motor vehicle storage, service or sales, a public garage and instructional studios one from the Planning Board (§ 250-32C).
• The schedule sets no minimum dwelling floor area in this district (§ 250-32K).

Planned Neighborhood Retail District - No side yard is required except as § 250-31L specifies. Height is limited to 2 stories, rising to 3 stories and 40 ft for fireproof or semi-fireproof construction (§ 250-31).

• A side yard that is provided must be at least 4 ft, and 6 ft where the lot adjoins a residence district line (§ 250-31L(2)).
• On a corner lot within 50 ft of a residence district line on the same block and side of the street, the side yard must equal half the front yard required in that residence district (§ 250-31L(3)).
• The frontage figure is the required street frontage, and the lot must also hold a circle 150 ft across with a building site inside it (§ 250-31F).
• The district also takes every use permitted in the residence districts as permitted there, and any dwelling units built here take the RA-1 usable open space requirement (§ 250-31I).
• The schedule sets no minimum dwelling floor area in this district (§ 250-31K).

Hotel District - Density is counted in sleeping rooms rather than dwelling units: no more than 13 sleeping rooms per acre, each at least 225 sq ft including its bathroom and closet, with no cooking facilities (§ 250-34C).

• The site must front at least 1,000 ft on a highway or street whose right of way is at least 100 ft wide (§ 250-34D(3)).
• The 12% covers the hotel and its accessory buildings together (§ 250-34E(1)).
• The floor area ratio is printed as 25% (§ 250-34E(3)).
• Height is measured from average grade to the eaves, and a pitched roof may reach 45 ft to the ridge or highest point (§ 250-34G).
• The developer or fee holder must deed 10% of the acreage being subdivided to the Village for recreation, or pay a fee in lieu (§ 250-34D(1)).

Planned Unit Development District - The residential part may hold up to 9,000 sq ft of floor area for every gross acre of it, and in no case more than six dwelling units per gross acre, with no dwelling unit above 30 ft (§ 250-7E(2)(d)[1]).

• The 30 acre figure is the minimum contiguous area that qualifies, unbroken by any public street, and a development may be placed only north of the Hutchinson River Parkway (§ 250-7E(2)(b)).
• The code publishes no yard dimensions. Instead a buffer runs around the perimeter totalling at least a quarter of the site, no less than 150 ft along a line abutting an existing road (§ 250-7E(2)(e)).
• That buffer is no less than 100 ft along a line abutting any district, or 50 ft where it abuts office or industrial development and the project includes senior living with adequate landscaping.
• An office or research laboratory part is held to a floor area ratio of 0.12 of the land given to it and to 35 ft, and a conference center may reach 40 ft (§ 250-7E(2)(d)[2]).
• A senior living facility may reach 35 ft, taken as the weighted average height from finished grade, and must stand at least 200 ft from a state road (§ 250-7E(2)(d)[5]).
• At least 10% of the site must be offered to the Village for recreation or a fee paid in lieu, and that land may still be counted in the density allocation (§ 250-7E(2)(f)[2]).

One-Family Residential District - Any subdivision of land here must follow the conservation subdivision procedure, and at least 20% of the acreage being subdivided must be preserved as public open space, which still counts in the lot area used to work out how many lots it may hold (§ 250-18.1N(2)).

• The 55 ft front yard is a floor: where the lots on both sides have deeper existing front yards, the required front yard becomes the average of those two (§ 250-18.1H(1)).
• The frontage figure is the required street frontage, and the lot must also hold a circle 166 ft across with a building site inside it (§ 250-18.1G).
• Gross floor area of the main building is capped by a formula rather than a ratio, 4,000 sq ft plus 0.11478421 of the lot area above 21,780 sq ft (§ 250-18.1F).
• A height to setback ratio also caps the building, 0.44 at the front and 1.20 at the side, each an inclined plane rising from average grade at the lot line (§ 250-18.1J).
• The 14% is main building coverage; § 250-37B allows another 4% for accessory buildings and 5% for decks, and counts porches toward lot area coverage.
• Total impervious coverage runs on a sliding schedule keyed to lot size rather than one percentage, and impervious surfaces in the front yard may not exceed 15% (§ 250-37C, § 250-37D).