BuildRules/London/Basement renovation

London project guide

Do you need a permit to renovate a basement in London, Ontario?

Check London basement permit rules for finishing living space, basement apartments, headroom excavation and below-grade entrances.

1 min readReviewed Oct 1, 2026

The short answerConditional

London requires permits for basement finishing that creates rooms or living space, basement apartments, excavation to increase headroom and below-grade entrances.

The City’s list separates cosmetic work from construction that changes use, structure or access.

Make this useful for my project

Know what matters

What changes the answer.

Start with these conditions. The official reference is attached to each one.

Finish rooms / living spacePermit requiredConditional

London lists basement finishing to create rooms or living space as permit-required.

Official sourceCity of LondonBefore you apply for a building permit · Residential permit triggers, exemptions and review timelines

Verified2026-10-01Open proof

Increase headroomPermit requiredConditional

Excavating to increase basement headroom is listed as permit-required work.

Official sourceCity of LondonBefore you apply for a building permit · Residential permit triggers, exemptions and review timelines

Verified2026-10-01Open proof

Below-grade entrance / walkoutPermit requiredConditional

London lists a below-grade entrance or basement walkout as permit-required.

Official sourceCity of LondonBefore you apply for a building permit · Residential permit triggers, exemptions and review timelines

Verified2026-10-01Open proof

Your preparation checklist

Your preparation progress

0 of 4 ready

Your progress is saved in this browser. Come back whenever you’re ready.

Building permit application
Existing and proposed floor plans
Structural/excavation details where applicable
Plumbing/mechanical information

Open the focused permit checklist

Fees and timing

TimelineLondon lists a 10-business-day statutory review timeline for renovations to houses once the application is complete.

FeesConfirm the current London permit fee for the exact project class before filing.

Next steps

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

Same project, different city

See how this rule changes across Ontario.

Compare the source-reviewed answer for this project across every municipality BuildRules currently covers.

Compare basement renovation rules by city

Better decisions, together

Get everyone on the same page.

Send this to your designer or contractor before agreeing on the scope.

Paid research brief

Get a clearer plan before you spend.

Turn the published rules, documents, timing and questions to verify into one project-specific preparation brief.

39 CADone-time

See what’s included

Research guidance only. Municipal approval and professional design are separate.

A little help with the next step

Move your basement renovation forward.

Tell us what kind of help you need. We’ll save the request with your project and municipality so a relevant provider can respond if a match is available.

BuildRules principle

Do not confuse “no permit” with “no rules.”

Zoning, overlays, safety rules and other constraints can still apply.

Keep exploring

Your next useful question.

A connected project guide or a practical next step, picked for this topic.

All project guides

Related project

What do you need for an additional residential unit in London, Ontario?

London treats ARUs as a dedicated permit path with zoning review, site planning and construction drawings.

1 min read