Islip, NY Accessory Structures: Garage Conversions (2026)

The Town of Islip Town Code (Chapter 68, e.g. Sec. 68-48 for the Residence AAA District) permits private garages 'provided that the gross floor area of garage space does not exceed the ground floor living area of the main dwelling,' and the design must be compatible with the residential character of the area, with exposed concrete block limited to 20% of the facade. Detached garages must adhere to accessory-structure setback and height regulations, and the maximum residential garage door height is 8 feet. A garage attached to the main structure by a shared wall may not exceed the height of the principal building. Converting a garage into habitable living space is not exempt: because an accessory apartment must be located within the principal structure and cannot be in an accessory structure (Town Code Art. XLVII), a detached garage cannot lawfully become a rental unit. Per the Islip Zoning FAQ, a second kitchen may only be allowed in single-family homes with a permitted accessory apartment or in permitted two-family, family-use-only dwellings; both uses require special exception approval from the Zoning Board of Appeals after a public hearing and must be renewed every three years (Town Code Secs. 68-600 and 68-419.1). Any interior alteration that changes the building layout requires a building permit, and a change-of-use permit is required when the proposed use differs from the last documented use on the certificate of occupancy.