Does a Shed Require a Building Permit in Boston?

When a Shed Requires a Permit in Boston

Boston generally requires a building permit for sheds over 120 square feet in floor area. This means a 10x12 shed (120 sq ft) is right at the threshold — a 10x16 shed (160 sq ft) clearly requires a permit. Any shed attached to the house or another structure requires a permit regardless of size. Sheds in Boston's historic districts may require Landmarks Commission approval for exterior appearance in addition to or instead of a building permit. Boston ISD permit requirements →

Setback Requirements in Boston

Sheds in Boston must comply with zoning setback requirements — minimum distances from property lines. In most Boston residential zones, accessory structures (sheds) must be set back a minimum of 3–5 feet from property lines. Corner lots have additional setback requirements from both street frontages. In the densely developed urban areas of Allston, Brighton, Dorchester, and East Boston where rear yards are small, these setbacks can significantly limit where a shed can be placed. Check Boston's zoning requirements for your specific address before sizing or locating a shed. Boston BPDA zoning resources →

Foundation Requirements for Boston Sheds

Small Boston sheds (under 120 sq ft) without permits can be installed on concrete deck blocks set on gravel — no frost-depth footings required for temporary structures. Permitted sheds with permanent foundations require footings to frost depth (42 inches in Boston) or a properly constructed floating slab on gravel that accommodates frost heaving. The tradeoff: a shed on deck blocks will shift slightly with freeze-thaw cycles and may require releveling; a shed on frost-depth footings stays in place permanently. For larger or more valuable shed installations, we recommend frost-depth footings for long-term stability. Massachusetts building code →

Consequences of Unpermitted Sheds in Boston

An unpermitted shed in Boston above the threshold size is a potential liability at home sale — buyers' attorneys pull permit histories and unpermitted structures are flagged. The Boston ISD can require removal of unpermitted structures or require retroactive permitting, which involves bringing the structure into compliance with current code. For a shed already installed, retroactive permitting requires as-built drawings, inspection, and potentially modifications if the shed doesn't meet current code requirements. Install with a permit when required — it's straightforward and eliminates future liability. Verify MA contractor license →