Smithtown, NY Accessory Structures: Garage Conversions (2026)

Turning a garage into habitable space is a 'change in the nature of the occupancy or use' of the structure, which § 112-10(A) requires a separate building permit for before any work begins, just like any other alteration or conversion. The applicant must file with the Chief Building Inspector on Town forms, describing the land, the existing and proposed use, the valuation of the work, and the owner's and applicant's contact information, and must submit duplicate plot plans and specifications showing the work's relationship to lot lines and neighboring structures (§ 112-10B, D).

45 per square foot of proposed work, listed alongside additions, alterations, fire repair, detached garages, decks and accessory structures. Because a garage conversion typically adds plumbing or heating fixtures, the applicant is also required, simultaneously with the permit, to submit a detailed drawing of the number and location of every plumbing fixture and heating unit and obtain a separate plumbing permit under § 112-10(E), billed under the plumbing-fixture fee schedule in § 112-11. If the conversion adds a fireplace, a further separate permit and drawing are required under § 112-10(F).

No certificate of occupancy for the converted space issues until every associated fee is paid and the Chief Building Inspector signs off on the completed work.