Plymouth County, Massachusetts

Massachusetts State Building Code (780 CMR)

• Current Edition: 10th Edition (effective July 1, 2025, based on 2021 IBC/IRC). The 9th Edition (2015 IBC base) remained in effect through June 30, 2025. Municipalities may adopt the 10th Edition on their own schedule during the transition period. Confirm which edition your local building department is currently enforcing.
• Construction Supervisor License (CSL): Required for structural work on structures larger than 35,000 cubic feet or for any structural work on smaller structures. CSL-U (unrestricted) covers all structures; restricted licenses limit the holder to 1-2 family residential work.
• Home Improvement Contractor (HIC): Registration required for contractors performing improvements on existing 1-6 unit owner-occupied residential properties. Separate HIC and CSL required for roof, siding, windows, and door replacement (effective July 1, 2008).
• Homeowner Exemption: Owners of 1-2 family dwellings may pull permits and supervise work on their primary residence without holding a CSL, but they assume full contractor liability and waive HIC Guaranty Fund protections.
• Permit Validity: Permits expire if construction has not commenced within 6 months of issuance, or if work is suspended or abandoned for 12 months. Renewal fees typically run 25-50% of the original permit fee.
• Coastal Floodplain: Plymouth County has extensive coastline with FEMA Special Flood Hazard Areas (Zones AE, VE). Properties in Marshfield, Duxbury, Plymouth, Kingston, and Rockland may require elevation certificates, lowest-floor documentation, and Chapter 91 (MassDEP waterways) licensing. Coastal construction must comply with 780 CMR flood-resistant construction standards.