Legal Basement Apartment

STEP 1: Confirm Zoning & Property Eligibility

Before doing anything, confirm your property is allowed to have a legal basement unit.

What to check:

• Property zoning (most residential zones allow 1 additional unit)
• Detached, semi-detached, or townhouse eligibility
• Maximum number of units allowed
• Parking requirements
• Lot size and setbacks

How:

• Contact City of London Planning & Development
• Or check online zoning map (GeoLondon)
• Ask specifically:

• • “Is a basement ARU permitted at my address?”

  • “How many units are allowed?”

✅ Do this first — zoning issues can stop the project entirely.

STEP 2: Initial Design & Feasibility Review

Assess whether your basement can physically meet code.

Key requirements:

• Minimum ceiling height:

  • 6 ft 5 in (1.95 m) clear height (may vary slightly with beams/ducts)

• Proper natural light:

  • Windows size must meet OBC bedroom/living room requirements

• Separate entrance:

• • Interior or exterior allowed

• Fire separation:

  • Required fire-rated assemblies between units

• Soundproofing:

  • OBC requires minimum sound transmission ratings

• Heating:

  • Independent or shared system with controls

⚠️ If ceiling height is insufficient, underpinning may be required.

STEP 3: Hire Qualified Professionals

You will likely need:

• BCIN-qualified designer (mandatory for permit drawings)
• Structural engineer (if underpinning or structural changes)
• HVAC professional
• Licensed electrician & plumber

Drawings must include:

• Floor plans
• Fire separations
• Egress windows
• Plumbing & electrical layouts
• Mechanical ventilation
• Smoke/CO alarms
• Parking layout (if required)

STEP 4: Apply for a Building Permit

This is mandatory.

Where:

• City of London – Building Division

Submit:

• Building permit application
• Construction drawings
• Designer Information Form
• Zoning confirmation
• Permit fees (based on square footage)

⏳ Review time:

• Typically 2–4 weeks (can be longer)

🚫 Do not start construction before permit approval

STEP 5: Fire Code & Life Safety Compliance

This is one of the most critical steps.

Requirements include:

• Fire separation:

  • Typically 30–45 minute fire rating

• Self-closing solid core doors

• Smoke alarms in:

  • Each bedroom

  • Hallways

  • Shared spaces

• Carbon monoxide detectors

• Fire blocking in concealed spaces

🔥 Fire inspections are strict — shortcuts fail inspections.

STEP 6: Egress & Windows

Each bedroom must have legal egress.

Minimums (typical):

• Window opening ≥ 0.35 m²
• Minimum opening dimension ≥ 380 mm
• No more than 1 m from floor to window sill
• Window well must allow full opening

🚪 If no window meets this, new egress windows must be cut

STEP 7: Plumbing, Electrical & HVAC

All systems must meet Ontario codes.

Plumbing:

• Separate or shared systems allowed
• Proper venting
• Backwater valve (often required)

Electrical:

• ESA inspection required
• Separate panel or sub-panel
• Arc-fault & GFCI protection

HVAC:

• Heat source required for each unit
• Proper ventilation & fresh air supply

STEP 8: Parking & Exterior Requirements

London typically requires:

• 1 additional parking space per new unit
• Must be legal size & surface
• Cannot block sidewalks or fire routes
• Also:
• Exterior entrance must meet safety and zoning rules
• Proper grading & drainage

STEP 9: Required Inspections (During Construction)

You must book inspections at each stage:

1. Framing
2. Plumbing rough-in
3. Electrical (ESA)
4. Insulation & fire separation
5. Final building inspection

❌ Missing inspections can invalidate the permit.

STEP 10: Final Approval & Occupancy

Once all inspections pass:

• City issues final approval
• Basement unit becomes a legal dwelling
• You may now:

• • Rent it legally

  • Insure it properly

  • Advertise it openly

STEP 11: Register Unit (If Required)

Some ARUs must be registered with the City.

• Property tax assessment updated
• Utility considerations
• Landlord obligations apply

Common Mistakes to Avoid

❌ Starting work without a permit
❌ Ignoring fire separation requirements
❌ Illegal ceiling height assumptions
❌ No egress windows
❌ Unlicensed contractors
❌ Skipping inspections

Typical Timeline

• Planning & design: 2–4 weeks
• Permit approval: 2–4 weeks
• Construction: 6–12 weeks
• Total: 3–5 months