Martin County, FL Accessory Structures: Shed & Carport Rules (2026)

Martin County sets one countywide shed rule in LDR § 3.201.C.1.a: one utility storage structure, incidental to a permitted use, with no more than 250 square feet of floor area. The paragraph sits under the heading "In all zoning districts," so the 250 square foot ceiling applies in agricultural, residential and commercial districts alike.

Authorization comes first. Section 3.201.A allows an accessory structure only when it is ancillary and incidental to the principal use, contributes to the comfort, convenience or necessity of that use's occupants, and sits on the same lot, or a contiguous lot under the same ownership or a homeowner's association, in the same zoning district. A shed on a lot with no principal use fails that test.

Timing comes second. Section 3.201.B.1 bars an accessory structure until all permits required for the principal use are issued. Only fences, walls and boat docks on single-family lots are exempt from that sequencing, so a shed waits for the house permit. Section 3.201.B.2 then holds the shed to every Article 3 standard that applies to the principal use unless specifically exempted.

Setbacks apply too. Section 3.16.A.1 requires structures to sit back from lot lines at least as far as Table 3.12.2 shows, and § 3.16.A.3 keeps every part of a required setback open space. The list of items allowed inside setbacks in § 3.16.B.1 names fences, driveways, docks, wells and similar items, not storage structures. Footnote (j) to Table 3.12.2 lets a setback dimension shrink to five feet for enclosed storage structures, greenhouses, a child's playhouse and gazebos, where a district's entry carries that footnote.

Coverage counts the shed. The code defines building coverage as the ground-floor area inside the exterior walls of the principal and accessory structures on a lot, so a 250 square foot shed uses up part of the district's coverage allowance.