Boston, MA Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Boston, MA, 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
- Max accessory building height
- 15 ft
- Min side lot line setback
- 4 ft
- Rear yard coverage cap
- Set by Table B (e.g., 25% in S-.3)
- Coverage cap applies in
- S, R and H districts
- Clearance from other yard projections
- 8 ft from accessory building
- Enforced by
- Building Commissioner
Summary
A shed or other accessory building in Boston's rear yard is capped at 15 feet in height and must sit at least 4 feet from any side lot line under Zoning Code Article 20, Section 20-2. In single-family, two-family and rowhouse districts, all accessory buildings in one rear yard together cannot exceed the coverage percentage Table B sets for that district.
Accessory buildings may be erected in a rear yard; provided that no such building is more than fifteen feet in height or nearer than four feet to any side lot line; and provided further, that in a S, R or H district the accessory buildings in any one rear yard shall not occupy in the aggregate a greater percentage of such rear yard than that specified in Table B of Section 13-1.
Full Breakdown
3 single-family district and twenty percent for 'other use' lots in the same district, so a homeowner has to check the specific figure for their zoning subdistrict rather than assume a flat citywide number. Section 20-1 establishes the baseline: the rear yard itself must otherwise stay free of structures, and Section 20-2 is the carve-out that lets sheds, garages and similar accessory buildings sit there. Section 20-3 adds a clearance rule for anything else projecting into the rear yard: projections allowed under Section 19-1 into side yards may extend the same distance into rear yards, but never within ten feet of the rear lot line or within eight feet of an accessory building, so a shed effectively creates its own no-build buffer around it.
Violations & Fines
The Building Commissioner enforces Article 20 under Section 5-1. An accessory building taller than 15 feet, built closer than 4 feet to a side lot line, or exceeding the Table B rear-yard coverage cap for its district is a zoning violation subject to a removal or correction order, and erecting one without the required building permit compounds the violation.
Frequently Asked Questions
How tall can a shed be in my Boston backyard?
How close to my side property line can I put a shed?
Is there a limit on how much of my backyard sheds and accessory buildings can cover?
Can another structure project close to my shed?
Sources & Official References
Other rules in Boston
How Boston compares: Shed Permit Requirements by City·Compare Boston to another location·View the Massachusetts accessory structures overview
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Shed & Carport Rules in Nearby Cities
How other cities in this county handle shed & carport rules.