A practical guide to Toronto's multiplex zoning, post-2023

What changed in 2023

In May 2023, Toronto City Council approved a city-wide bylaw amendment permitting up to four residential units on most lots previously zoned for single-family or duplex use. The change applied across the bulk of Toronto's "Neighbourhoods" land-use designation — the low-rise residential band that covers most of the city outside its mid- and high-rise corridors.

The reform was modest in language and significant in effect. Where a homeowner once had to assemble a rezoning application to add a third or fourth unit, the same building program is now broadly available as-of-right. That single shift has unlocked a far larger pool of feasible sites for small-scale multiplex development.

When a sixplex or larger is allowable

Four units is the as-of-right floor in most areas — and Council has since pushed the envelope to six units, so a sixplex today is largely an as-of-right building in Toronto: for most lots there's no Committee of Adjustment hearing and no public process, just a permit application. The remaining variables are your specific zoning category and the performance standards that come with it.

The bigger 2024 change is the Major Streets bylaw. As part of the City's Expanding Housing Options in Neighbourhoods (EHON) program, Council adopted permissions — in force as of late 2024 — for small-scale apartment buildings of up to six storeys and as many as sixty units on lots fronting designated major streets, alongside townhouses up to four storeys. For an ordinary residential lot that happens to front a major street, this is transformational: the ceiling jumps from a handful of units to a genuine multiplex, much of it achievable without a full rezoning. It is the single most under-appreciated opportunity in the current rulebook — and it's where we spend much of our time.

The catch most people miss: at six storeys you trigger a second means of egress and a stack of other code step-ups, and building efficiency drops fast if the floor plate isn't designed around them from the first sketch. Laying out a six-storey, sixty-unit building that's actually efficient — where the rentable area survives the corridors, stairs, and exits — is its own discipline. It's one we've built the firm around.

Beyond what these layers permit as-of-right, a project still reaches for a minor variance at the Committee of Adjustment to adjust the envelope, or — for larger massing, added height, or sites assembled across multiple lots — a rezoning application. Knowing which lever applies to a given lot, and exactly how far it can be pushed, is most of the work.

The lot-size question

The bylaw doesn't impose a hard minimum lot size — it relies on the existing performance standards (setbacks, lot coverage, and, for apartment buildings, floor space index) to constrain what fits. So the real question isn't "is my lot big enough?" — it's "what's the most this lot can carry?"

A few realities from our own work, which sits at the larger end of the missing middle:

• You need less frontage than people assume. A fourplex fits comfortably on a modest lot, and a sixplex-and-up works just fine on a 25-foot frontage. 91 Barton, for instance, is a 25′ × 160′ lot — and it carries 11 units.
• Depth does the heavy lifting. For the larger purpose-built rental buildings we specialize in, depth matters more than width. Roughly 120 feet or more opens up the most efficient layouts; a deep lot is what makes a high unit count possible.
• Configuration matters. A regular rectangular lot beats a wide-shallow or pie-shaped one for almost every program.

Setbacks, lot coverage, and FSI

Here's a distinction that trips most people up. A multiplex (up to six units) and many Major Streets forms aren't governed by a floor space index (FSI) cap the way people expect — setbacks, height, and lot coverage do most of the constraining. But the moment a building reaches seven units, the City treats it as an apartment building, and FSI requirements apply. Since seven-plus units is exactly where we operate, FSI is usually the constraint that defines our buildings — and extracting the most livable floor area within it is a big part of the job.

We won't recite specific numbers here — they vary parcel-by-parcel, and the by-law to read is your own zoning category's, not a summary article. What we'd flag instead is the interaction between the limits: it's common for a lot to hit FSI before coverage, or vice versa, and whichever bites first is the one that shapes the building.

As-of-right vs. minor variance vs. rezoning

Three categories worth keeping straight:

• As-of-right: the building conforms to every applicable standard. The permit application goes directly to the Building Division — the fastest path.
• Minor variance: the project needs relief from one or more standards, decided at a Committee of Adjustment hearing. It adds time, and it's where inexperience shows — but it's a process we run constantly, and knowing how to prepare and present an application is most of the battle. One recent change worth knowing: a Committee approval can no longer be appealed by third parties — only the applicant can appeal a refusal — so the neighbour risk that used to hang over these files is largely gone. What's left is schedule, and schedule is manageable.
• Rezoning: the program isn't contemplated by the existing zoning, so it goes through the full Planning Act process — public consultation and council approval. It's the longest path, and the one where having a partner who's done it before matters most.

Every path beyond as-of-right carries some risk — that's real. But "risk" mostly means "uncertainty about an outcome," and uncertainty shrinks dramatically with experience. We've taken projects through all three paths; across 10+ approvals — including five that went to appeal — we have a 100% success rate. With the right team, the harder paths aren't something to fear. They're completely manageable, and they're usually where the value is.

Common mistakes we see

Recurring themes from owners who come to us mid-project:

• Forgetting about servicing sizing. The water service, sanitary connection, and electrical capacity on a single-family lot were never sized for a seven-, ten-, or eighteen-unit building. Upgrades to the service line, panel, or transformer can be the costliest surprise on the file — and they have to be planned from day one.
• Not thinking about the end user. Hitting the maximum unit count means nothing if the units don't live well. We design backwards from the tenant — light, storage, sound separation, family-sized layouts — because a building that leases fast and keeps its tenants is worth far more than one that simply wins a number on paper.
• Ignoring the laneway. If a rear laneway runs behind the lot, a garden or laneway suite is often part of the highest-and-best-use answer — and its access, setback, and servicing rules differ from the principal building.
• Assuming heritage doesn't apply. Heritage Conservation Districts and listed properties carry additional review layers that the 2023 reform did not waive. Worth checking before design starts.
• Forgetting the tree bylaw. Mature trees on or adjacent to the lot can constrain the building footprint and add permitting steps and replacement costs.

What this means in practice

The post-2023 framework — and the 2024 Major Streets layer on top of it — is a genuinely good operating environment for infill. Whether your lot is a candidate for a fourplex, a sixplex, or something much larger comes down to frontage, depth, the zoning category your parcel sits in, whether it fronts a major street, and the servicing reality below grade. The cheapest hour you can spend at the start is the one where someone reads the actual bylaw against your survey — and asks not just what's allowed, but what could be.

That second question is the company's ethos in a sentence: highest and best use, taken literally. For most of the industry it's appraisal jargon. For us it's the operating discipline — a refusal to leave value in the ground. Every site we touch gets designed to the full measure of what the rules and the lot will responsibly carry: every buildable foot, every door, every dollar of land value actually earned rather than left behind. A lot gets redeveloped once in a generation; we design like that's true.

That's also where we focus as a business. We take projects from a zoning strategy through approvals and into construction — development management and construction management under one roof. See our page on large multiplexes for where we concentrate (with fourplexes and sixplexes for smaller schemes), and our project portfolio for sites that took every path described above — as-of-right, minor variance, and full rezoning.