Chelsea, MA Accessory Structures: Shed & Carport Rules (2026)

Chelsea's accessory-use ordinance, Sec. 34-50, governs sheds and other detached structures on residential lots. Subsection (c) sets the baseline placement rule for every accessory building or structure: none may sit within the required front yard, and none may come closer than five feet to a side or rear lot line, without a special permit from the zoning board of appeals. To get that permit, the owner must show that adequate access remains on the lot for emergency equipment to reach the rear of the principal building, and, if the structure is a garage, that placing parking elsewhere would cause substantial hardship without harming neighboring properties or street traffic.

Subsection (f) then lists which accessory uses are allowed as of right in the R1, R2 and NHR residential districts, and paragraph (f)(5) names private accessory structures not operated as part of a business, such as a private greenhouse, work shop, tool shed, bathhouse, garage or swimming pool, as a permitted category, so a residential tool shed does not need a special permit for its use, only compliance with the front-yard and five-foot side/rear setback in subsection (c). Subsection (b) caps accessory floor area at 25 percent of the floor area covered by the related occupancy permit for any accessory use within a building other than a garage.

Because a shed is a structure under this chapter, it also falls under Sec. 34-76's requirement that no structure be erected except in conformity with the dimensional table at Sec. 34-262, and under the building permit and occupancy permit process of Sec. 34-209, administered by the building inspector.