Project template
Your preparation checklist
Use it as a working list. The final submission still needs to match your actual scope and the City’s current requirements.
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What to do next
- Define the basement rooms and use
- Identify excavation or walkout work
- Prepare structural and floor-plan drawings
- Use the ARU route if another dwelling unit is being created
Official sources behind this page
Finish rooms / living spacePermit required
London lists basement finishing to create rooms or living space as permit-required.
City of LondonBefore you apply for a building permit · Residential permit triggers, exemptions and review timelines
2026-10-01Open proof
Increase headroomPermit required
Excavating to increase basement headroom is listed as permit-required work.
City of LondonBefore you apply for a building permit · Residential permit triggers, exemptions and review timelines
2026-10-01Open proof
Below-grade entrance / walkoutPermit required
London lists a below-grade entrance or basement walkout as permit-required.
City of LondonBefore you apply for a building permit · Residential permit triggers, exemptions and review timelines
2026-10-01Open proof
Need the full project answer?
The main guide keeps the permit trigger, zoning questions, documents, fees, timing and next steps together.
Open the basement renovation guide