London · Basement Renovations
Basement Renovations in London, Ontario
Section 4.37 of London’s Zoning By-law Z.-1 bars a rental unit in any basement whose finished floor sits below the sanitary sewer serving the house. That one elevation decides whether a London basement renovation can include a suite. Old East Village and Wortley Village cellars add a second hurdle: about 1.7 to 1.9 m of headroom.
Basements in London
What’s different in London
| Permit office | City of London Building Division (official site, opens in a new tab) |
|---|---|
| Sewer-level rule | No ARU where the finished basement floor is below the sanitary sewer serving the building. |
| Bedroom limit | Two bedrooms per ARU under Interim Control By-law CP-1600-300. |
| Basement heights | 1.7–1.9 m in pre-1920 cellars, about 2.1 m in post-war bungalows, 2.4 m or more in new builds. |
| Flooding grant | City pays 90% of eligible costs: up to $1,600 for a backwater valve, $3,100–$3,900 for a sump. |
| Rental licence | Applied for after final inspection, with a floor plan, self-certification checklist and fire inspection. |
Worth knowing first
Old East and Wortley cellars: underpin, or rent elsewhere on the lot
Inside the old ring around downtown, a London basement is a cellar. Stone or rubble walls, patches of concrete over dirt and 1.7 to 1.9 m of headroom are normal in Old East Village and Wortley Village. Underpinning a typical 1890s house and pouring a lowered slab costs $50,000 to $100,000 before HST, on top of the finish. It needs an engineer’s design and a building permit. No heritage permit is needed, because the work is below grade. If the budget won’t stretch, the cellar suits storage, laundry and a workshop. The rental unit then goes in an addition or a backyard building under Z.-1.
The scope, pricing tiers and 5-step process are the same everywhere we work. See Basement Renovations ›
Frequently asked questions
Basements in London: three local questions
Not under the current rule. Section 4.37 of Z.-1 doesn’t allow an ARU in a basement whose finished floor is below the sanitary sewer serving the building. We confirm the elevation from the City’s sewer information and a camera inspection of your lateral before any design. A basement that fails the Section 4.37 test can still be family space, with an ejector pump for the bathroom.
It can, if your house qualifies. The City of London grant pays 90% of eligible costs up to set maximums, for example $1,600 for a backwater valve and $3,100 to $3,900 for a sump pit and pump with the weeping tiles disconnected. It applies to homes whose foundation drains connect to the sewer, common in houses built before 1985. It doesn’t pay for finishing.
Apply for a building permit as if the unit were new, then open enough wall and ceiling for the inspector to see framing, wiring and plumbing. Most London conversions need upgraded ceiling fire separation, interconnected smoke and CO alarms, a code-sized egress window and the 2-bedroom maximum under CP-1600-300. After final inspection you apply for the rental licence. Plan on 6 to 10 weeks with tenants moved out.
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