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London ARU guide

Basement Apartment Vs Garden Suite In London, Ontario

A basement conversion usually uses an existing shell; a garden suite creates a separate building and a larger site-work decision. The right route depends on the house, lot, privacy goals, servicing and budget.

Reviewed 2026-07-20 · Independent information, not City approval

Run The Property Screen
Decision guide

Check the property before you spend on plans

Use the lot, funding, rent-cap and servicing screens to decide whether the next step should be design work, a builder conversation or more research.

  • Check the address
  • Compare funding agreements
  • Confirm the rent math
  • Budget the hidden costs

Cost And Construction Disruption

Basements can reduce foundation and exterior-envelope costs but may require underpinning, waterproofing, fire separation, egress and service upgrades. Garden suites add a new foundation, structure, utility trenching, grading and access work.

Zoning And Site Exposure

An interior unit depends heavily on building-code and existing-house conditions. A detached unit adds yard placement, setbacks, lot coverage, trees, drainage and construction-access constraints.

Privacy, Rent And Long-Term Use

Garden suites usually provide stronger separation. Basement units can be faster and less expensive on the right house. Compare realistic rent, financing and owner-use plans rather than choosing only from a model image.

Funding And Permit Route

London's current incentive structure can consider multiple ARU types. The funding agreement and permit path still need to match the actual project.

Side-by-side

First-pass comparison

Use these as planning tendencies, not quotes.

What to compare
Basement/interior ARU
Detached garden suite
Existing shell
Usually reused
New building
Site work
Often lower
Often substantial
House disruption
Higher
Lower after construction
Lot constraints
Lower
Higher
Privacy
Shared building
Separate building

FAQ

Common questions, answered plainly

Is a basement ARU always cheaper?

No. Existing structure, moisture, ceiling height, exits, services and fire separation can make a basement conversion expensive.

Check The Property

Screen the site before selecting the ARU type.

Run The Property Screen

Next checks

01 London ARU Zoning Rules Check zoning, setbacks, lot coverage, and detached ARU placement rules. 02 Cost To Build A Detached ARU Review construction, servicing, permit, insurance, tax, and development charge risks. 03 London ARU Grant Guide Compare the current grants and separate repayable loan before you spend on drawings.