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

1, accessory structures including sheds are permitted by-right citywide, meaning the Building Official does not require a special permit for an accessory use unless the shed is being built before the principal building exists on the lot. The Building Official also has to find that the structure is customarily accessory, clearly incidental and subordinate to the principal building in area, size, function and location, and under the same ownership before it counts as an accessory structure at all. 1(f) flatly forbids encroaching into the maximum front setback, so a shed cannot sit in front of the house closer to the street than the district's front setback line allows.

2(u) then sets the shed-specific dimensional cap: a shed, defined as a roofed structure used as storage space, may be up to twelve feet in height. That is taller than several other listed accessory structures in the same section, such as chicken coops and cold frames capped at eight and six-and-a-half feet respectively, but the ordinance treats sheds as their own category with their own twelve-foot ceiling rather than folding them into a general accessory-building limit. Because the height and setback standards sit inside the zoning ordinance rather than the general code, any dispute over a shed's compliance runs through the Building Official and, on appeal, the Zoning Board of Appeals rather than through a separate accessory-structure permit process.