BuildRules/Cambridge/Windows / doors

Cambridge project guide

Do you need a permit for window or door changes in Cambridge?

Check Cambridge permit requirements for new or altered windows and doors, including enlarged openings.

1 min readReviewed Oct 1, 2026

The short answerConditional

Cambridge lists new or altered windows and doors, such as increasing an opening size, among typical permit-required projects.

The permit question is tied to modifying the opening and structure rather than simple finish work.

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Know what matters

What changes the answer.

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

New window / doorPermit requiredConditional

Cambridge lists new windows or doors among typical building-permit projects.

Official sourceCity of CambridgeBuilding Permits · Permit triggers for structures, garages, openings and retaining walls

Verified2026-10-01Open proof

Larger openingPermit requiredConditional

Increasing the size of an existing opening is explicitly given as an example.

Official sourceCity of CambridgeBuilding Permits · Permit triggers for structures, garages, openings and retaining walls

Verified2026-10-01Open proof

Structural reviewOpening changes are reviewed under the Building CodeInfo

Cambridge reviews permit plans for Ontario Building Code and applicable-law compliance.

Official sourceCity of CambridgeBuilding Permits · Permit triggers for structures, garages, openings and retaining walls

Verified2026-10-01Open proof

Your preparation checklist

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Existing and proposed opening dimensions
Plan/elevation
Structural header/lintel information
Building permit application

Open the focused permit checklist

Fees and timing

TimelineConfirm the current municipal review timeline after the application is accepted as complete.

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

Next steps

Measure the existing opening
Define the proposed size/location
Identify structural framing changes
Apply before altering the opening

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.

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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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Your next useful question.

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

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