# Ontario Basement Apartment Legalization: Code Requirements, Permit Process & Full Costs

**URL:** <https://home.renovation.reviews/t/ontario-basement-apartment-legalization-code-requirements-permit-process-full-costs/46866>\
**Category:** Ontario\
**Created:** [April 26, 2026, 6:30pm UTC](https://home.renovation.reviews/t/ontario-basement-apartment-legalization-code-requirements-permit-process-full-costs/46866 "2026-04-26T18:30:02Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![system](https://home.renovation.reviews/user_avatar/home.renovation.reviews/system/32/77_2.png) [@system](https://home.renovation.reviews/u/system)\
**Post date:** [April 26, 2026, 6:30pm UTC](https://home.renovation.reviews/t/ontario-basement-apartment-legalization-code-requirements-permit-process-full-costs/46866/1 "2026-04-26T18:30:02Z")

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Illegal secondary suites expose Ontario homeowners to serious liability — no insurance for tenant injuries, municipal fines, and buyer deal-breakers at sale. Legalizing creates legal rental income and adds real property value. Here is how to do it.

**Ontario Building Code Requirements**  
Minimum ceiling height: 1.95m in habitable rooms. Egress window in every bedroom: minimum 0.35 sq m openable area, minimum 380mm high and wide, maximum sill height 1m above floor. Smoke and CO detectors interconnected between units. Fire separation between units: typically 30-minute rated drywall assembly on ceiling/walls. Separate entrance (exterior or through common area). Minimum bedroom: 7 sq m.

**Permit Process**  
Apply for building permit as secondary suite addition. Toronto, Ottawa, and Hamilton have simplified secondary suite permit pathways. Inspection stages: framing, insulation, drywall, final. Permit fees: $500-$1,500.

**Costs**  
Minor compliance only (egress windows, smoke/CO interconnect): $5,000-$15,000. Full legalization with egress windows, fire separation, electrical sub-panel, bathroom: $20,000-$50,000. Typical GTA payback: 2-3 years at $1,400-$2,000/month rental income.

**Bill 23 Impact**  
Bill 23 reduced development charges for secondary suites in most Ontario municipalities and streamlined approvals.

Share your legalization experience at home.renovation.reviews.