What it costs to build an ADU in Mechanicville, NY

R Residential - The 4,000 sq ft minimum is for building on a lot previously of record. New dwelling construction on a lot not previously of record needs at least 5,000 sq ft, so check the deed before assuming 4,000.

• A two-family dwelling is a permitted principal use and the second unit costs 2,500 sq ft on top of the 4,000 sq ft base, so 6,500 sq ft in all, plus 250 sq ft of usable open space.
• Each dwelling unit in excess of the first adds 2,500 sq ft of lot area and 250 sq ft of usable open space on top of the district minimum: three units need 9,000 sq ft, four need 11,500.
• The two side yards must add up to at least 14 ft, so 5 ft and 5 ft conforms on the one-side rule and fails the sum.
• A multiple dwelling is a special use here, and the land it needs depends on the unit count through that additive rule.
• A use listed as permitted in, or excluded from, a district is deemed excluded from any more restrictive district unless the text says otherwise, so a permission does not travel down.

MFTR Multifamily/Townhouse Residential - The code states no maximum height and no coverage cap in MFTR, and that is its own position rather than a gap: the R district's three stories, 40 ft and 40% coverage do not apply here.

• § 200-12D gives a single-family home 4,000 sq ft and all other residential structures 5,000 sq ft, and § 200-12C adds 2,500 sq ft of lot area for each dwelling unit in a structure of 2 units or more.
• So a 4-unit building needs the greater of 5,000 sq ft and four times 2,500, which is 10,000 sq ft; above two units the density rule is what binds.
• Condominiums, townhouses and multifamily structures of two or more units, for sale individually or for rent, are all principal permitted uses, with no special use permit anywhere in the district.
• More than one principal structure may stand on one lot of record, which is what makes a townhouse cluster deliverable without subdivision.
• The two side yards must add up to at least 14 ft, with at least 5 ft on any one side, and that sum applies to any principal building on the lot.

GC General Commercial - The code sets no minimum lot area, width or depth here and no front yard, so a building may stand on the front property line on a lot of any size. A one-family dwelling is permitted by right, while a two-family or a multiple dwelling needs a special permit.

• The district has no minimum lot area except where a dwelling use is provided, and then it requires 2,500 sq ft of lot area and 250 sq ft of usable open space for each dwelling unit.
• The side yard rises from at least 5 ft to at least 10 ft where the lot abuts any land in a residence district.
• A use listed as permitted in, or excluded from, a district is deemed excluded from any more restrictive district unless the text says otherwise, so a permission does not travel down.

RC Restricted Commercial - No new dwelling use is permitted in RC except a multiple dwelling by special permit. Coverage is 60% for non-resident use and drops to 50% on any lot with a dwelling use.

• The code sets no minimum lot area or dimensions here, but a dwelling use adds 2,500 sq ft of lot area and 250 sq ft of usable open space for each dwelling unit.
• The 10 ft front yard exists to provide access drives and off-street parking, so it is not space to build or landscape on.
• Where the rear yard abuts a residence district it must be at least 10 ft.
• The side yard rises from at least 5 ft to at least 10 ft where the yard abuts a residence district.
• A use listed as permitted in, or excluded from, a district is deemed excluded from any more restrictive district unless the text says otherwise, so a permission does not travel down.

LI Light Industrial - No new dwelling use is permitted in LI in any form, so the residential permissions that reach GC stop at this line. The yards are not stated in this district at all: they are the same as GC's, and a change there moves this district too.

• The side yard rises from at least 5 ft to at least 10 ft where the lot abuts any land in a residence district.
• A junkyard is the only special use.
• Every industrial use must also produce no objectionable effluent, odor, smoke, dust, fumes, light, noise, radiation or other effect in any residence district area.
• A use listed as permitted in, or excluded from, a district is deemed excluded from any more restrictive district unless the text says otherwise, so a permission does not travel down.

WMU Waterfront Mixed Use - The zero front and side yards are the code's own figures, so a building may stand on the front and side lines. Multiple principal uses are permitted on any lot, which with 90% coverage and 75 ft of height is what makes a genuine mixed-use block deliverable.

• One-family and multi-family dwellings, apartments and condominiums are permitted by right here, alongside offices and a broad retail and commercial list, and nothing in it needs a special use permit.
• No per-unit land requirement is stated for multi-family here, unlike R, GC and RC, which each impose 2,500 sq ft and 250 sq ft of usable open space per unit.
• Density is not settled either way, so confirm unit count with the Building and Code Department at (518) 664-9884 before underwriting it.
• The code states a lot area and no lot width or depth at all.
• Parking under § 200-30 is the only other constraint the district names, subject to the shared parking and cross easement provisions of § 200-16(AA)C.

PDD Planned Development District - The 1 acre minimum attaches to a commercial or light industrial use rather than to the district as a whole, and there is no maximum coverage restriction at all. The whole envelope can be modified or waived by the ZBA/Planning Commission.

• The code sets no minimum lot width, no minimum lot depth and no minimum front, rear or side yard, and says so in terms.
• A project with less acreage will be considered where the applicant demonstrates that the objectives of the article are met, so the acre is a starting point rather than a threshold.
• The acre excludes existing streets, easements and dedicated land or water areas above 5% of the minimum gross acreage.
• A site proposed for two or more of the listed use types must carry the aggregate gross land area required for each.
• No residential use is permitted. The uses run to retail in a planned shopping complex of at least three acres, indoor amusement, health care, office, hotel, parking, park, church and light industrial.
• Once a site plan is approved it locks: no change to the structures, amenities or approved uses without resubmission to the ZBA/Planning Commission.