Cambridge basement permit: when you need one and what to submit
The short answer
Cambridge doesn't name basements, but new walls, changed room uses and plumbing all need a permit, so a typical basement finish does too. City fee: $0.50 per sq ft, minimum $143, plus a $25 zoning review.
Last verified 2026-10-07 · City of Cambridge: Building permits, City of Cambridge Fees and Charges By-law 25-079, 2026 (PDF), City of Cambridge: Additional residential units- City fee
- $0.50 per sq ft, minimum $143, plus a $25 zoning review
- Where to apply
- City of Cambridge application portal
Up to two additional units (three in total) are allowed with a building permit.
What an application usually includes
Cambridge’s checklist has the exact list; apply through City of Cambridge application portal.
- Existing and proposed floor plans with room names and sizes
- Ceiling heights, beams and ducts
- Window details for bedroom escape
- Insulation and energy information, and heating and ventilation where they change
- The application form and the owner or designer declaration
Local quirks
- No water in a pool or hot tub until the City's final inspection, and building before the permit doubles the pool permit fee.
- A deck has to stay at least 3.0 m (about 10 ft) from the rear lot line.
- Removing or damaging a private tree 20 cm (8 in) across or more needs its own tree permit.
Design your Cambridge basement to the Building Code.
The design, drawings and code checks work in Cambridge today. Cambridge’s own forms aren’t built in yet, so you’ll fill those in on the City’s portal.