Cambridge building department

The Cambridge Inspectional Services Department (ISD) issues building, electrical, plumbing, gas, mechanical, sprinkler, sign, and demolition permits for property in the City of Cambridge. It enforces the Massachusetts State Building Code and parts of the State Sanitary Code. It also enforces the city’s Zoning Ordinance and supports the Board of Zoning Appeal (BZA). Middlesex County does not issue building permits; every Cambridge address goes through ISD.

What needs a building permit

Anyone who will construct, alter, repair, or demolish a structure, or install a sign, needs a building permit before work starts, posted at the job site. Asbestos removal and demolition permits are types of building permit. Ordinary repairs, as the Building Code defines them, are exempt.

ISD’s FAQ answers a few common questions:

Question	ISD answer
Shed	No building permit if the shed is under 120 square feet. Sheds of any size must still meet the Zoning Ordinance. See shed permits.
Re-roofing	Only one layer of existing roofing may stay in place.
Deck guardrails (one- and two-family)	A deck more than 30 inches above grade needs a guardrail at least 36 inches high.

Approvals to get before you apply

ISD routes each application to other city departments first, and you are responsible for getting their approvals:

• Zoning. Work must comply with the Zoning Ordinance; ISD or Community Development staff can confirm. Some projects need BZA relief first.
• Historical Commission. Required for historic and neighborhood conservation districts, landmarks, and preservation restrictions, and to demolish any structure over 50 years old.
• Curb cuts. A new or expanded curb cut needs City Council approval before the permit can issue.
• Larger projects. May also need Community Development, Public Works, Traffic/Parking/Transportation, and Fire sign-off.

How to apply

Cambridge takes building permit applications through its OpenGov online portal. The city lists six online building permit types: New Construction, Addition/Alteration, Roof, Siding, Solar, and Tent.

1. Create a portal account, fill out the application, and upload documents as PDFs. ISD publishes estimated- and final-cost-of-construction affidavits.
2. Send all messages to staff through the portal’s Comments section, not by direct email.
3. After the non-ISD approvals are done, ISD invoices the permit fee. You can pay online by credit card or e-check, with added service fees, or by check at the ISD counter.
4. ISD does not consider the application received until the invoice is paid and processed. ISD then issues or denies the permit within 30 days. That clock stops while ISD waits on any extra information it asked for.
5. Pick up the printed permit card at the ISD counter. Keep it posted at the site until the work is finished.

Work must start within six months of permit issuance and continue steadily until it is done. Any change to the approved work needs a modification to the original permit.

Scam warning: In November 2025 the city warned of fake fee invoices emailed to permit applicants under real staff names. Real city emails end in @cambridgema.gov, and the city never asks for gift cards, wire transfers, or payment apps.

Who can pull a permit

• Licensed construction supervisors. ISD issues building permits to construction supervisors licensed by the City of Cambridge or the Commonwealth. A state license only covers structures under 35,000 cubic feet. The city sells its own building license for $50 for the first two years, and renewals are $50.
• Homeowners. Homeowners can get a building permit for work on a one- or two-unit dwelling they live in or plan to live in, and they must file a Homeowner’s Affidavit. ISD warns they may be liable for contractors on the property and lose Home Improvement Contractor law protection, so it encourages using a licensed contractor. See owner-builder permits.
• Trades. Electrical permits go only to Massachusetts-licensed electricians. Plumbing and gas permits go only to Massachusetts-licensed plumbers and gasfitters.

Fees

Item	Fee
New construction, repairs, alterations, demolition, foundation-only permits, plan amendments	$20 per $1,000 of construction cost, $50 minimum
Same work on buildings with three or fewer dwelling units	$15 per $1,000, $50 minimum
New signs	$10 per $100 of sign cost, $20 minimum
Certificate of occupancy, residential	$100 for the first unit, $50 for each additional unit
Certificate of occupancy, commercial	$100 plus $50 per 1,000 sq. ft.

If work that needs a permit starts before the permit is issued, the fee triples. Trade fees have their own pages on the ISD site. BZA hearing fees are separate. For example, an addition or alteration needing a variance or special permit costs $200 plus $50 per 100 square feet of construction that needs relief.

Codes in effect

ISD reports that the 10th edition of the Massachusetts State Building Code took effect on October 11, 2024. Applications received on or after January 1, 2025 must use the 10th edition.

Cambridge adopted the Massachusetts Specialized Stretch Energy Code on January 23, 2023, effective July 1, 2023. According to the city, it requires:

• Buildings with fossil-fuel systems must be pre-wired for future electric systems. Commercial buildings and smaller residential buildings must also have solar.
• Multifamily buildings over 12,000 sq. ft. must meet Passive House standards or net-zero home performance scores.
• Small residential buildings with parking must be wired for at least one EV charger. Multifamily, residential, and business parking must have 20% of spaces wired.

Cambridge’s Fossil Fuel-Free Ordinance took effect on March 22, 2024. It requires new construction and major renovation projects, residential and non-residential, to be fossil fuel-free.

Inspections and certificates of occupancy

The assigned building inspector follows a permit from start to finish, which can mean inspections from excavation through rough to final. Electrical and plumbing/gas permits get at least a rough and a final, and the building inspector cannot approve the next step until those trade inspectors sign off. The city’s step-by-step permit guide says the owner or the owner’s representative must tell the building inspector when work is complete so a final inspection can be done. ISD’s website does not describe an online inspection request process, so contact your assigned inspector. The Building Division page lists each inspector’s direct phone number.

A certificate of occupancy needs final inspections and, where applicable, a final cost affidavit and completion affidavits from the designers and contractor.

Hours and work-hour limits

Since January 1, 2026, ISD is open Monday 7:00 a.m. to 6:00 p.m., Tuesday through Thursday 7:00 a.m. to 3:30 p.m., and Friday 7:00 a.m. to noon. Building inspectors are at the counter 7:00 to 8:30 a.m. each weekday, plus 3:30 to 5:30 p.m. Monday, 2:30 to 3:30 p.m. Tuesday through Thursday, and 11:00 a.m. to noon Friday.

City Ordinance 8.16 limits construction in residential areas to 7:00 a.m. to 6:00 p.m. on weekdays and 9:00 a.m. to 6:00 p.m. on Saturdays. Sunday work needs a special permit from the Police Department.

Past permits, plans, and certificates of occupancy are kept in the ISD record room on the lower level of 831 Massachusetts Avenue (copies $0.20 per page, $4.00 per plan sheet).