London project guide

Do you need a permit for a deck in London, Ontario?

Check London deck permit rules for the 600 mm height threshold, attachment to the house and published setback guidance.

1 min readReviewed Oct 1, 2026

The short answerConditional

A side or rear deck under 600 mm can be permit-exempt only when it is not attached to the house; an attached low deck still requires a permit.

London combines height and attachment in its homeowner guidance and also publishes zoning setback information for decks.

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Know what matters

What changes the answer.

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

Under 600 mm + detachedPermit not requiredConditional

London states that a side or rear deck under 600 mm does not need a permit if it is not attached to the house.

Official sourceCity of LondonCommon homeowner projects · Deck permit and zoning guidance

Verified2026-10-01Open proof

Under 600 mm + attachedPermit requiredConditional

The City states that the same low deck requires a permit if attached to the house.

Official sourceCity of LondonCommon homeowner projects · Deck permit and zoning guidance

Verified2026-10-01Open proof

Over 0.61 mPermit requiredConditional

London’s building-permit trigger list identifies decks greater than 0.61 metres high 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

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Building permit application
Site plan
Deck/framing drawings
Setback and height information

Open the focused permit checklist

Fees and timing

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

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

Next steps

Measure height above grade
Confirm whether the deck attaches to the house
Check zoning setbacks
Apply when the permit trigger applies

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 deck rules by city

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

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BuildRules principle

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

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

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