Accessory Structures in Islip, NY (2026)
5 verified accessory structures rules for Islip, New York, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Islip allows an accessory apartment only within the existing structure of an owner-occupied single-family home, on a lot of at least 7,500 square feet, after a Zoning Board of Appeals public hearing and a permit that must be renewed every three years.
Islip Accessory Apartment Permit (Town Code Art. XLVII)
Heavy RestrictionsTown of Islip Town Code Ch. 68, Art. XLVII, Accessory Apartments (Sec. 68-600 et seq.)
No accessory apartment permit shall be granted nor shall any said permit remain valid unless an owner of the lot upon which the accessory apartment is located resides within the principal dwelling unit. ... An accessory apartment shall not be located within an accessory structure.
Shed Rules
A shed in Islip may be built without a permit if it is 144 square feet or less, no more than 8 feet high, has no electric or plumbing, is the only shed on the lot, and meets setbacks; larger or taller sheds require a building permit.
Islip Shed Rules - No Permit Under 144 sq ft / 8 ft
Some RestrictionsTown of Islip Zoning FAQ - 'Can a shed be built without a permit?' (Division of Building); see Town Code Sec. 68-23(C)(2)
Yes, a shed can be built without a permit, provided that the shed: does not have electrical or plumbing services; does not exceed 144 sf; does not extend more than 8 feet (high) above the property grade; is used only for the storage of items customarily incidental to a residence; is detached on the same plot of land as a single or two-family dwelling; is the only shed on the property; complies ...
Garage Conversions
Islip permits private garages whose gross floor area does not exceed the main dwelling's ground-floor living area, but converting a garage to living space or adding a second kitchen requires Building Division permits and, for an accessory apartment, Zoning Board of Appeals special-exception approval.
Islip Garage & Conversion Rules (Town Code Ch. 68)
Some RestrictionsTown of Islip Zoning FAQ - 'Are second kitchens permitted in a single-family home?'; see Town Code Secs. 68-600 and 68-419.1
A second kitchen may be allowed in single-family homes with permitted accessory apartments or in permitted two-family, family use only dwellings. ... Both uses require special exception approval from the Zoning Board of Appeals, after due public hearing, and must be renewed every three years.
Carport Rules
Carports and other accessory structures in Islip follow the same accessory-building rules: no placement in the primary front yard, size-based side and rear setbacks of 2 to 10 feet, a 14-to-18-foot height cap, and no more than 25% rear-yard occupancy.
Islip Accessory Structure Setbacks & Coverage (Sec. 68-45)
Some RestrictionsTown of Islip Zoning FAQ - 'Where can an accessory structure be placed?' (Division of Building); General Zoning Standards Chart
An accessory structure may not be located in a primary front yard, with the exception of Residences on Fire Island, and is subject to front, side, and rear-yard setbacks based on the size of the accessory structure. ... Side and Rear Yard Setbacks - if the structure is: Less than or equal to 144 sf, it must be a minimum of 2 feet from the side and rear yard property lines. Greater than 144sf an...
Tiny Homes
Islip has no tiny-home ordinance; a standalone tiny house on wheels or a separate small cottage is not a permitted use, and the only path to a small second dwelling is an accessory apartment within an owner-occupied principal home meeting the New York State Uniform Code.
Islip Tiny Homes - No Standalone Tiny Dwelling Allowed
Heavy RestrictionsTown of Islip Zoning FAQ - 'What is Floor Area Ratio?' (Division of Building); see Town Code Ch. 68, Art. XLVII
Residential accessory structures less than or equal to 499 sf, or 249 sf in Residence BAA-District, will not be counted toward FAR. However, if an accessory structure is improved with plumbing fixtures, its gross floor area will be counted toward FAR, regardless of size.
Looking for Suffolk County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Islip city rules.
Accessory Structures in Suffolk County →