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Smithtown, NY Building Safety: Building Permits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Permit issuer
Chief Building Inspector
Shed exemption
Under 144 sq ft, 12 ft high
Residential permit fee
$305 base + $0.55/sq ft
Commercial permit fee
$550 base + $0.65/sq ft
First offense fine
$1,000-$2,500
Repeat offense fine
Up to $15,000

Summary

Smithtown requires a separate building permit from the Chief Building Inspector before almost any construction, alteration, demolition or change of use, with narrow exemptions for ordinary non-structural repairs and small tool sheds. Applications need scaled plot plans, a licensed architect's or engineer's seal on most projects, and payment of set fees before work can start.

No person, firm or corporation shall commence the erection, construction, enlargement, alteration, removal, improvement, demolition, conversion or change in the nature of the occupancy or use of any building, structure or site or cause the same to be done, without first obtaining a separate building permit from the Chief Building Inspector for each such building, structure or site, except that no building permit shall be required for: 1) the performance of ordinary repairs which are not structural in nature and 2) a detached residential storage or tool shed that is an accessory structure to a one- and two-family dwelling, provided gross floor area of the shed does not exceed 144 square feet, the shed does not exceed 12 feet in height, and the shed is located in a conforming location on the property.

Full Breakdown

Section 112-10 of the Building Construction chapter bars anyone from commencing the erection, enlargement, alteration, removal, demolition, conversion or change in occupancy of any building, structure or site without first obtaining a separate permit from the Chief Building Inspector for each building or structure. The only exemptions are ordinary non-structural repairs and a detached residential tool or storage shed under 144 square feet and 12 feet high in a conforming location. Applications go to the Chief Building Inspector on Town forms and must describe the land, state the proposed use, give the valuation of the work, identify the owner and applicant, and attach duplicate plot plans and specifications showing lot lines, distances to adjoining structures, and street grades (§ 112-10B, D).

Plans generally require the seal of a licensed architect or professional engineer under Education Law § 7302, though the Inspector may waive that for minor alterations. Anyone obtaining a building permit who is also installing plumbing fixtures or a fireplace must simultaneously submit a separate detailed drawing and obtain a distinct permit for each (§ 112-10E, F). 65 per square foot for new commercial construction; no permit or certificate issues until all fees are paid. 1, added in 2025, requiring OSHA-trained workers and a designated Site Safety Designee on commercial projects over 35,000 square feet.

Violations & Fines

Building without a required permit, or working outside its terms, violates § 112-23 and is treated as a misdemeanor for jurisdictional purposes. A first offense carries a fine of $1,000 to $2,500; a second offense within five years, $2,000 to $5,000; and a third offense within five years, $4,000 to $15,000 or up to six months in jail, or both, with each day of continued violation a separate offense. The Chief Building Inspector can also issue a stop-work order, and no certificate of occupancy issues while any fine or stop order remains open.

Frequently Asked Questions

Do I need a permit to remodel my Smithtown house?
Almost always, yes. Section 112-10 requires a separate building permit for any alteration, addition, conversion or change of occupancy, not just new construction. The only exceptions are ordinary repairs that are not structural and a small accessory tool shed under 144 square feet and 12 feet tall in a conforming location.
What has to be included with a Smithtown building permit application?
You need Town forms describing the land and proposed use, the valuation of the work, owner and applicant contact information, and duplicate plot plans and specifications showing lot lines, distances to neighboring structures, and street grades, per § 112-10(B) and (D). Most plans need a licensed architect's or engineer's seal.
What happens if I build without a permit in Smithtown?
You face a misdemeanor-level violation under § 112-23: a fine of $1,000 to $2,500 for a first offense, rising to $4,000-$15,000 or up to six months in jail for a third offense within five years. The Building Department can also issue a stop-work order and withhold your certificate of occupancy until fines are paid.

Sources & Official References

Other rules in Smithtown

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