Portland, ME Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Portland, ME, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Rear setback, ≤250 SF shed (RN-1–4)
- 5 ft.
- Rear setback, ≤250 SF shed (RN-6)
- 3 ft.
- Side setback, ≤250 SF shed (RN-1/2)
- 5 ft.
- Side setback, ≤250 SF shed (RN-3/4)
- 3 ft.
- Max accessory structure height
- 18 ft. (RN-1–RN-3)
- Permit required
- Yes, Code of Ordinances § 6-92
Summary
A small shed or detached accessory structure of 250 square feet or less can sit as close as 5 feet to the rear lot line in Portland's RN-1 through RN-4 zones (3 feet in RN-6), with interior side setbacks as tight as 3 feet in RN-3/RN-4, and its height is capped at 18 feet under Land Use Code Table 7-A.
TABLE 7-A: RESIDENTIAL NEIGHBORHOOD ZONE DIMENSIONAL STANDARDS. Rear setback (min.), Detached accessory structures (≤250 SF footprint): RN-1 5 ft.; RN-2 5 ft.; RN-3 5 ft.; RN-6 3 ft. Side setback, interior (min.), Detached accessory structures (≤250 SF footprint): RN-1 5 ft.; RN-2 5 ft.; RN-3 3 ft.; RN-4 3 ft. Detached accessory structure height (max.): RN-1 18 ft.; RN-2 18 ft.; RN-3 18 ft.
Official source re-checked September 7, 2026: the cited page had not changed since it was quoted.
Full Breakdown
3, sets separate, and looser, setbacks for detached accessory structures of 250 square feet or less than for the principal house, recognizing that a garden shed or small detached garage has less impact on neighbors than a house or a larger outbuilding. In the rear yard, a 250-square-foot-or-smaller accessory structure needs only 5 feet of clearance from the rear lot line in the RN-1, RN-2, RN-3, and RN-4 zones, dropping to 3 feet in RN-6. On the interior side, the same size structure needs 5 feet in RN-1 and RN-2, but only 3 feet in RN-3 and RN-4.
Once an accessory structure exceeds 250 square feet, it is treated as a principal structure for setback purposes and must meet the larger front-, rear-, and side-yard setbacks that apply to houses in that zone. Height for any detached accessory structure in the RN-1, RN-2, and RN-3 zones is capped at 18 feet, measured the same way as principal-structure height under Article 7's rules of measurement, where a story exceeding 18 feet counts as two stories. Because construction of any building or structure in Portland requires a permit from the building authority under Code of Ordinances § 6-92, a shed or detached garage, regardless of size, needs a permit before it goes up, and the Permitting and Inspections Department checks the proposed footprint against these Table 7-A setback and height figures at that stage.
Violations & Fines
Erecting or enlarging an accessory structure that violates Table 7-A's setback or height standards is a Land Use Code violation under § 1.5.2, punishable under Code of Ordinances § 1-15 by a fine of $100 to $500 per offense, with each day the violation continues counted separately. Building a shed without first obtaining the Chapter 6 permit exposes the owner to the same escalating per-day penalties and to a stop-work order under § 6-95(a) halting further construction until it is remedied.
Frequently Asked Questions
How close to my property line can I put a shed in Portland?
Do I need a permit to build a shed in Portland?
How tall can a backyard shed or detached garage be?
Sources & Official References
Other rules in Portland
How Portland compares: Shed Permit Requirements by City·Compare Portland to another location·View the Maine accessory structures overview
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