What Lot Do You Need for a Sixplex in Toronto? The Frontage Math That Decides the Build
The short answer: the nine as-of-right wards set the boundary — but eligibility is decided lot by lot (zoning, overlays, geometry; a zoning review is step one). On most standard residential lots the envelope can hold six units — but the building you can fit changes completely as frontage narrows or widens, and that changes the rent roll more than the location does. The zoning tells you what's permitted. The floor plate tells you what's profitable.
Updated August 2026 · MBL Developments
The math that governs everything
Start with three constraints that apply broadly across the multiplex standards (confirm your exact lot with a zoning review):
- Side setbacks take roughly 0.9m off each side — a 30-ft lot leaves ~24 ft of buildable width
- Building depth caps around 19m (~62 ft) from the front wall — a deep lot doesn't help the main building past that
- Height allows 3 storeys (up to 4 in the sixplex wards, but the 10.5m height cap makes a true fourth storey a design battle — most schemes are 3 storeys plus a lower level)
Multiply it out: a 30-ft lot yields a floor plate of roughly 1,500 sq ft per level — four levels, ~5,900 sq ft of building.
Why frontage decides your unit mix — and your income
Here's the part nobody runs: six units across four levels means two levels must hold two units each. On a 1,500 sq ft plate, any floor you split produces one decent unit and one small one — and small units are where rent rolls die (a 1-bedroom earns $1,500–2,000/month less than a 3-bedroom on nearly the same footprint).
- On narrower lots: the main building carries full-floor units on the upper levels, splits below — and the highest-rent configuration usually needs a rear suite (laneway or garden suite) to carry the final family-sized unit. A deep lot handles this comfortably.
- On wider lots: the plate reaches ~2,000+ sq ft per level — two units per floor, both full-sized, all in one building. Simpler build, same rent roll.
Same zoning, same neighbourhood — but the wider lot builds a fundamentally simpler project. That's worth real money, and it's rarely priced in.
What else the lot must clear
- Trees: one protected tree in the building envelope can redesign your project or stall demolition for months. Survey before you waive conditions.
- Easements and mutual drives: shared driveways and rights-of-way can kill a footprint outright. Title review is not optional.
- Lane access: determines whether the rear suite is a laneway suite (needs the lane) or a garden suite (doesn't), and where parking lives.
- Services and grade: older streets sometimes need service upgrades; a favourable grade makes lower-level units brighter and more rentable.
Frequently asked questions
Can you build a sixplex on a 25-foot lot? Legally, often yes. Practically, the plate gets tight and the unit mix compresses toward smaller, lower-rent units. The economics need careful modelling — this is exactly where per-lot underwriting matters most.
Is a corner lot better? Frequently — corner exposure can relax the effective width constraint and improve light for more units. Case-by-case, but a corner can genuinely help the plate.
Does a deeper lot mean a bigger building? Not for the main structure (the ~19m depth cap governs), but depth is what makes a rear suite comfortable — and the rear suite is often where the best unit in the project lives.
We publish the math we actually use — closed rents, real costs, lot screening.