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.
0 of 4 ready
Your progress is saved in this browser. Come back whenever you’re ready.
What to do next
- Measure the existing and proposed opening
- Confirm whether size or location changes
- Identify structural framing affected
- Apply before creating or enlarging the opening
Official sources behind this page
New windowPermit required
Mississauga lists new windows among projects requiring a building permit.
City of MississaugaWhen a building permit is required · Windows, doors, plumbing, basement walkouts and underpinning
2026-10-01Open proof
New or enlarged doorPermit required
The City lists adding a new door or increasing the size of an existing door as permit-required.
City of MississaugaWhen a building permit is required · Windows, doors, plumbing, basement walkouts and underpinning
2026-10-01Open proof
Same-size replacementPermit not required
Replacing an existing window or door with the same size is listed as permit-exempt.
City of MississaugaWhen a building permit is required · Windows, doors, plumbing, basement walkouts and underpinning
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 windows / doors guide