Why fourplexes get all the attention: they're the sweet spot where the zoning, the construction cost per unit, and the rental income line up. One building, one lot, four rents — without the years-long process of larger development.
Where it's allowed
In Toronto, fourplexes are permitted city-wide, as-of-right. No rezoning, no public meeting — a standard residential lot can hold four self-contained units, and parts of the city now allow up to six. Across the rest of the GTA, three units are the as-of-right baseline, with a fourth often achievable through municipal permissions or a minor variance.
This guide is written around the GTA playbook, but the conversion logic travels: in Vancouver the multiplex zoning allows up to six units (eight if all rental) on a standard lot, and Edmonton permits up to eight as-of-right — see the zoning guide for your city's envelope.
What a conversion actually involves
- Layout — a typical two-storey house divides into basement, main-floor and upper units, with the fourth coming from a second-storey split, an addition, or a rear/garden structure depending on the house.
- Fire separations — rated assemblies between units, interconnected smoke and CO alarms throughout.
- Exits — every unit needs safe egress; this drives more design decisions than anything else.
- Kitchens, baths & services — each unit is fully self-contained; electrical is upgraded (and ESA-inspected), and utilities are often separately metered so tenants pay their own.
- Ceiling heights & structure — the usual make-or-break items a feasibility review checks before you fall in love with a layout.
The honest numbers
A typical GTA conversion of a two-storey house runs in the $680k–$980k all-in range, and units like these lease for roughly $2,100–$2,700/month each depending on size and city. Financed against the once-built value, the rents service the debt — that's the scenario that matters, and it's what your free report models.
What blocks conversions
- Servicing capacity — water and sewer connections sized for one home sometimes need upgrading for four.
- Structural surprises — some houses take a split gracefully; others fight it. A site review catches this early.
- Parking and access — requirements have relaxed, but tight lots still need a plan.
- Financing sequencing — the #1 avoidable failure: starting construction without the refinance path mapped. Map it first.