Multiplex Zoning in Toronto: What's As-of-Right and What Still Needs Approval

Toronto's zoning by-law gives "multiplex" a precise, narrow meaning: a residential building with two, three, or four dwelling units, with at least one unit sitting wholly or partly above another. That covers a duplex, a triplex, or a fourplex, and the term is legally distinct from an "apartment building," a category the by-law reserves for structures of seven units or more. Since May 2023, that two-to-four-unit form has been as-of-right on almost every low-rise residential lot in the city: no rezoning, no committee hearing, just a building permit checked against the zoning standards. Since June 2025, a defined band of wards allows up to six units under the same house-form rules; everywhere else the ceiling is still four. Heritage districts, an odd lot shape, or a site-specific zoning exception can still pull a given address out of as-of-right and into a variance, which is what the rest of this piece maps.

What the By-law Actually Calls a Multiplex

"Multiplex" gets used loosely in real estate conversation, covering almost any small multi-unit building. The zoning by-law is stricter. It defines a multiplex as a residential building with two, three, or four dwelling units, a duplex, a triplex, or a fourplex, with units stacked at least partly on top of each other rather than arranged side by side only. That definition matters because it sets the building form the rest of the zoning envelope measures against: a multiplex is treated as a house, not as an apartment building. The by-law's "apartment building" category starts at seven units, which is why the height, coverage, and setback rules below read the way they do rather than the way they would for a mid-rise.

In the wards covered by the 2025 expansion (see the timeline below), the same house-form concept stretches further. Buildings of five or six units, sometimes called a "houseplex," are permitted there while still sitting inside the detached-house built-form standard rather than being reclassified as an apartment building.

The Reform Timeline: From Restricted to As-of-Right, 2023 to 2025

Three decisions did the work, on top of a provincial floor.

Date	Decision	Where it applies
Nov. 28, 2022	Ontario's Bill 23, the More Homes Built Faster Act, receives Royal Assent, setting a provincial floor of up to three residential units as-of-right on most serviced urban lots, with no municipal by-law amendment required	Province-wide floor
May 10, 2023	Toronto Council adopts an Official Plan Amendment (Law No. 0473) and a Zoning By-law Amendment (Law No. 0474), permitting multiplexes of up to four units as-of-right on every lot zoned RD, RS, or RT in a Neighbourhoods designation	Citywide
June 25-26, 2025	Council adopts an Official Plan Amendment and Zoning By-law Amendment (Law Nos. 2025-0653 and 2025-0654, plus monitoring by-law Law No. 2025-0648), enabling residential buildings of up to six units as-of-right	Toronto and East York Community Council wards, plus Ward 23 (Scarborough North)
July 24-25, 2025	Council waives development charges and parkland dedication cash-in-lieu on all units, up to six, in eligible multiplex and sixplex developments, including combinations with a garden or laneway suite	Eligible developments citywide

Toronto's own by-law already went further than the provincial floor: Bill 23 guarantees three units, Toronto's May 2023 amendment guarantees four, citywide. A study to extend six-unit as-of-right permission to every low-rise Neighbourhoods lot, not just the wards covered in June 2025, was underway as of this writing but had not been adopted.

Where Multiplexes Are As-of-Right Today

For nearly every lot zoned RD, RS, or RT in a Neighbourhoods designation, a multiplex of up to four units is as-of-right. Six units are as-of-right only inside the Toronto and East York Community Council wards and Ward 23. Outside that footprint, four units remain the ceiling until the citywide six-unit study, if adopted, changes it. Storeys reported on the July 2025 development-charge decision that Toronto's sixplex permission still falls short of the federal requirement to legalize sixplexes citywide, a requirement that remains unfulfilled outside the wards the June 2025 amendment covers.

The Envelope That Governs an As-of-Right Build

Being as-of-right does not mean unregulated. A multiplex still has to fit a defined envelope; it just does not need a variance to do it, provided the design stays inside these numbers.

Standard	What applies
Height	The Height Overlay mapped for that lot, with a floor of 10 metres even where the map shows less; multiplexes are exempt from the Overlay's separate cap on number of storeys
Floor Space Index (the "d" value on the zoning map)	Does not apply to multiplexes, unless a Chapter 900 site-specific exception says otherwise
Setbacks	The same front, side, and rear setbacks that apply to any other permitted house form in the same zone; there is no separate, looser setback rule for multiplexes
Lot coverage	Whatever the zone's standard requires, though a Chapter 900 site-specific exception can set a different coverage, height, or setback number for an individual lot
Parking	None required. Toronto removed minimum parking requirements for residential uses citywide as of Feb. 3, 2022. Parking built voluntarily still has to meet the by-law's design standards

That Chapter 900 line matters more than it looks. By-law 569-2013's Chapter 900 holds hundreds of site-specific exceptions, and a lot governed by one can carry different height, coverage, or setback numbers than the generic rule for its area. Checking a specific address against its own exception, rather than relying on its base zone label, is worth doing before treating the table above as the final word for that lot.

Multiplex, Garden Suite, Laneway Suite, or Severance: Which Tool Fits the Lot?

These four tools solve different problems and get confused constantly. A multiplex adds units inside one building on the lot already owned. A garden suite and a laneway suite work differently again: each adds a second, separate building elsewhere on the lot instead of expanding the main house, and each has its own envelope rules covered in their own pieces in this cluster rather than repeated here. A severance does not add a unit at all. It splits one lot into two or more separate legal properties through a Consent application to the Committee of Adjustment. The Committee reviews the split against the Official Plan and zoning, weighs servicing capacity and flood risk, and factors in heritage considerations, then requires a minimum of 14 days' public notice before a hearing.

These tools are not mutually exclusive. The City's July 2025 development-charge waiver explicitly covers multiplex and sixplex developments built in combination with a garden or laneway suite on the same lot, which is a sign the City treats stacking these tools on one property as an ordinary outcome, not an edge case.

As-of-Right Permit or Minor Variance?

An as-of-right multiplex moves through a standard building permit application, with a zoning examination to confirm compliance. Nothing more is required if the design fits inside the envelope above. The moment a design misses a numeric standard, whether that is height, a setback, lot coverage, parking, or an angular plane rule, the project needs a minor variance from the Committee of Adjustment before a permit can issue. That is the practical line between "as-of-right" and "needs approval": not the number of units, but whether every number on the drawings already fits the zone.

Severance runs on a separate track entirely: splitting a lot needs its own Consent application, judged against the Official Plan, zoning, servicing, flood risk, and heritage factors, with at least 14 days' public notice before a hearing. A severance can be pursued alongside a multiplex build, but it stays a distinct approval with its own timeline.

What Knocks a Lot Out of As-of-Right?

Two overlays do most of the work of pulling a specific address out of as-of-right.

Heritage conservation districts are the first. Multiplexes, laneway suites, and secondary suites remain permitted uses inside a heritage conservation district. But the City's own HCD guidance is clear that alterations, additions, or new construction on a listed or designated property still go through separate heritage review under the Heritage Register or the district plan. That review sits on top of the zoning permission; it does not replace it, and it does not disqualify the use, just the as-submitted design.

Chapter 900 site-specific exceptions are the second, and the less visible one. Because Chapter 900 can assign an individual lot a different height, coverage, or setback number than the general zone rule for its area, a lot that looks textbook as-of-right on the base zoning map can still fail one of those numbers once its own exception is checked. There is no shortcut around this: the exception has to be pulled for the specific address, not inferred from the neighbours.

Where to Go Next

This piece answers the definitional question: what a multiplex is, and where the current rules put it. Where you go next depends on where the project actually stands. Screening a lot for feasibility means looking at the site's actual buildable envelope and cost lines. For unit mix and rent, the cluster's financing and feasibility pieces run the numbers. Comparing neighbourhoods means comparing lot sizes and overlay patterns across wards. And a lot that already has a laneway or garden suite in mind, or a severance on the table, needs the rules specific to that tool, not a repeat of the zoning definition covered here.