Toronto's Sixplex By-law Permits Detached Buildings Only

Toronto's By-law 654-2025 lets a single detached house grow into a six-unit building, but the permission stops at the property line of a semi-detached or rowhouse lot. The by-law defines a sixplex as a type of detached houseplex, and it separately bars converting any part of a semi-detached houseplex, a semi-detached house, or a townhouse into a five- or six-unit building by adding dwelling units. It also applies as-of-right in specific wards only, and it raises the height ceiling on top of the general multiplex rules covered in TESA's Multiplex Zoning in Toronto: What's As-of-Right and What Still Needs Approval. On top of that, it drops the floor space index cap that would otherwise limit how much building a lot can carry.

What By-law 654-2025 Actually Changed

Toronto City Council enacted By-law 654-2025 on June 26, 2025, under Planning and Housing Committee Item PH22.4 and Mayoral Decision 10-2025. It amends Zoning By-law 569-2013 and builds directly on the general houseplex framework that By-law 648-2025 set up earlier in 2025.

Under the amended definitions, a sixplex means a building located on a single lot with six dwelling units, with at least one unit entirely or partially above another. That distinction matters: a detached house with a secondary suite is not a sixplex, and a sixplex is not an apartment building. The by-law is explicit that a sixplex is a type of detached houseplex, not a separate use category with its own rulebook. It inherits the general houseplex regulations, including one that removes the floor space index cap entirely. The zoning by-law's maximum FSI does not apply to a detached houseplex, sixplex included, so unit count and building envelope rules do the limiting instead of a floor-area ratio.

Why the City Limited Sixplexes to Detached Buildings

The detached-only rule is not implied: it is written twice into the by-law. First, the amended "detached houseplex" definition requires the building to sit entirely on one lot and be "not attached to a building on an abutting lot," which is the structural test a semi or a rowhouse unit fails by design. Second, the by-law adds a direct prohibition: no portion of a semi-detached houseplex, a semi-detached house, or a townhouse may be converted to a fiveplex or sixplex through the construction of additional dwelling units.

What is still allowed is a straight conversion in the other direction: a detached house can be converted directly into a five- or six-unit detached houseplex and keep its lawfully existing status, as long as the added units stay entirely within the building as it existed before the permit was issued. That is a narrower path than it sounds. It rules out bumping the building envelope to fit six units in, and it rules out the semi-detached and rowhouse stock that makes up a large share of Toronto's low-rise streets. TESA's Where a Fourplex Is Legal in Toronto and What the Zoning Requires covers the same detached-houseplex mechanics at the four-unit scale, where the same attachment test applies.

Lot Size, Frontage, and Density Thresholds

The by-law's main lot-level mechanism is a unit-count override, not a new size test. Wherever a zone's density label carries a "u" value below six, the by-law raises the maximum permitted dwelling units on that lot to six. The text does not add a separate minimum lot area or minimum frontage specific to a five- or six-unit houseplex beyond what already applies to a detached house sitting on that lot. In practice, that means a lot that already supports a lawful detached house is not automatically screened out on size grounds once it clears the other sixplex tests. The zone's existing lot-area and frontage standards, plus any overlay, still have to be met.

The FSI exemption described above carries the same weight here: a detached houseplex, including a sixplex, is not measured against a floor-area ratio cap. Height, setback, and coverage rules do the shaping instead.

One cost detail worth flagging early in a feasibility check: Toronto expanded its development charge exemption on July 24, 2025, so the second through sixth dwelling unit in a development of up to six units on a residential lot is exempt from development charges under Toronto Municipal Code Chapter 415, section 415-6A(2). Confirm the current exemption wording and any conditions directly with the City before building it into a pro forma.

Height, Parking, and Other Standards That Scale Up

The base houseplex height limit is 10.0 metres. By-law 654-2025 allows a five- or six-unit detached houseplex to rise to 10.5 metres, but only when three conditions are all met at once: the ceiling joists of the lowest level sit between 1.0 and 1.5 metres above established grade; that lowest level carries a minimum 2.4-metre floor-to-ceiling height across at least 80% of its floor area; and that level wholly or partially contains a dwelling unit. Miss any one of the three and the building is held to the 10.0-metre limit, so a design that only checks the joist elevation against grade can still fall short on ceiling height or on whether that level actually holds a unit.

Parking is one requirement that does not scale up with unit count. Toronto has not required on-site parking for multiplex-type residential buildings since February 3, 2022, and neither the general multiplex framework nor By-law 654-2025 adds a parking minimum tied specifically to five or six units. Beyond height and parking, the zone and overlay standards that already govern a detached house on that lot continue to apply on top of the sixplex permission itself.

Where a Sixplex-Eligible Lot Most Often Fails

Two problems account for most of the promising lots that do not clear the sixplex test before drawings start.

The first is building form. A semi-detached house, a rowhouse unit, or any building attached to a structure on an abutting lot is excluded outright, no matter how large the lot or how much frontage it carries. The by-law's conversion bar on semi-detached houseplexes, semi-detached houses, and townhouses is absolute, not a variance-eligible threshold.

The second is geography. Toronto City Council's June 25-26, 2025 vote confined as-of-right sixplex permission to the Toronto and East York Community Council boundaries as they existed on that date: an area of eight wards, plus a defined part of Ward 23 in Scarborough North bounded by Steeles Avenue, Neilson Road, the Rouge River, Highway 401, and Midland Avenue. Council did not extend the permission citywide. The remaining 16 wards were left out of the June 2025 decision, though each can separately request that the Chief Planner extend sixplex permission to it. A lot with a detached house, ample frontage, and no attachment issue can still fail the test simply by sitting outside those boundaries.

Severance Instead of a Sixplex

Building six units on one lot is not the only way to add density, and it is not always the better return. Splitting the lot into two goes through the same body as a sixplex variance, Toronto's Committee of Adjustment, but as a distinct application type: a consent, commonly called a severance. A consent application can divide land into new lots, add land to an abutting lot, or establish an easement, provided the resulting lots meet the applicable zoning requirements on their own.

Severance tends to beat a sixplex when a lot fails the detached-only test outright, when the frontage and depth comfortably support two conforming lots with houses or smaller multiplexes on each, or when the site sits outside the eligible wards and a sixplex is not available as-of-right at all. It is worth running as a real alternative, not an afterthought, on any lot wide enough to raise the question.

Bridging a Near-Miss With a Minor Variance

A lot that clears the detached-form and ward-boundary tests but misses one specific number (a height figure, a setback, a coverage threshold from an overlay) is not automatically out. It can apply to the Committee of Adjustment for a minor variance. The Committee can only grant one if it passes all four tests set out in Planning Act section 45(1): the variance maintains the general intent of the Official Plan, maintains the general intent of the Zoning By-law, is appropriate for the land, and is minor. All four have to hold; a variance that is small in magnitude but changes the character the by-law was protecting still fails the test.

Confirming Eligibility Before You Pay for Drawings

The by-law's detached-only rule, ward boundaries, and height conditions interact in ways that are easy to misread from the text alone. Before commissioning drawings, request a Zoning Review at a Toronto Building Division customer service counter. Staff return a written list of the specific by-law sections a proposed sixplex does not yet comply with. That review is also the standard first step before filing any Committee of Adjustment application for a variance or a severance. It costs a fraction of a design fee and settles the detached-form and ward-boundary questions before either becomes an expensive discovery.