Chelsea, MA Accessory Structures: Carport Rules (2026)

Carports in Suffolk County are treated as accessory structures under zoning and require building permits under 780 CMR. Boston Zoning Code Article 10 (Dimensional Regulations) and district-specific articles set carport dimensions: typically maximum height 15 feet, maximum area 300-500 sq ft depending on district, minimum side and rear setback 3-5 feet (interior) or matching the principal structure setback in some districts. Carports cannot project into the front yard in most districts. Chelsea Zoning Ordinance §34-200 treats carports as accessory structures with 3-foot side setback in residential zones. Revere Zoning §17.20 allows accessory structures including carports with 3-5 foot setbacks. Winthrop Zoning Bylaw §17.08 requires carports to meet accessory structure setbacks. All four municipalities apply the State Building Code (780 CMR Chapter 16 and Chapter 24) for structural requirements: wind loads (100+ mph coastal), snow loads (40-50 psf), and proper anchoring. Pre-fabricated metal carport kits still require permits and must meet these loads — wind uplift is a major concern in coastal Revere and Winthrop. Foundation requirements: concrete piers or slab typically. Pre-fab car-ports that are open on 3+ sides may be exempt from some Energy Code requirements. Electrical permits needed if lighting or outlets are installed. Historic district carports in Boston's Back Bay, Beacon Hill, South End, and similar require Commission approval. Setback violations may trigger mandatory variance from Zoning Board of Appeals.