Ayer, MA Permit Requirements: Renovation Permits (2026)

Massachusetts General Laws Chapter 143 requires that no building be constructed, reconstructed, altered, repaired, removed, or demolished without a building permit, except for work classified as ordinary repairs. The Massachusetts State Building Code (780 CMR) defines exempt work and sets requirements that apply across all Middlesex County municipalities. Exempt work (no permit needed): painting, plastering, replacement of flooring, minor repairs (fixing a leaky faucet without moving pipes, replacing broken glass, patching holes), replacing kitchen cabinets, and installing countertops — all provided no structural, plumbing, electrical, or mechanical systems are altered. Work requiring permits: structural modifications (removing/adding walls, enlarging openings, new foundations), all electrical work (must be performed by a licensed electrician in Massachusetts), all plumbing and gas work (must be performed by a licensed plumber), HVAC installation or replacement, roofing (re-roofing permits required), window or door replacement that changes rough opening size, insulation work, and any addition of habitable space. Massachusetts has notably strict contractor licensing requirements: all home improvement contractors must register with the state under MGL Chapter 142A (Home Improvement Contractor Registration). Electrical, plumbing, and gas work must be done by appropriately licensed professionals. Local building departments in Middlesex County issue permits and conduct inspections. Larger cities (Cambridge, Lowell, Somerville) have more complex processes, while smaller towns may have simpler procedures. Historic districts add a layer of review for exterior changes.