London basement permit: when you need one and what to submit
The short answer
Yes. Finishing any part of a basement needs a building permit. City fee: $3.68 per m² of renovated floor, minimum $260.37.
Last verified 2026-10-07 · City of London: Common homeowner projects, City of London Building By-law B-7, Schedule A (2026–27 fees), City of London: Additional residential units- City fee
- $3.68 per m² of renovated floor, minimum $260.37
- Where to apply
- City of London Development and Business Portal
- Review time
- The City aims to review a complete deck or house renovation application in 10 business days (15 for a second unit).
A second unit needs a building permit and a residential rental unit licence.
What an application usually includes
London’s checklist has the exact list; apply through City of London Development and Business 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
- A low deck still needs a permit if it's attached to the house. One City list suggests otherwise; the deck page is the one to follow.
- Pool fences must be at least 1.53 m (60 in) high, taller than in many Ontario cities.
- London has opted out of the Line Fences Act: if neighbours can't agree, costs are only shared for a 1.22 m (4 ft) chain-link fence.
Design your London basement to the Building Code.
The design, drawings and code checks work in London today. London’s own forms aren’t built in yet, so you’ll fill those in on the City’s portal.