October 8, 2026

Building a Multiplex in Toronto: Rules, Approvals and Budget

Toronto lets you build a multiplex of up to four units on almost any residential lot in the city without rezoning, and up to six units in the Toronto and East York district and Ward 23 in Scarborough. A fourplex built within the zoning rules needs a building permit and nothing more from City Planning. Since July 2025 the City charges no development charges or parkland fees on the second to sixth units of a multiplex on one lot. Whether a multiplex in Toronto works on your lot comes down to the zoning detail, who designs it, what it costs beyond construction and how long it takes before rent comes in.

Every rule and fee below was checked against City of Toronto and Ontario sources on October 7, 2026. It isn’t legal or tax advice.

What Toronto allows for a multiplex

A multiplex, in the City’s words, is a building with “2 to 6 homes (dwelling units) in one residential building” (City of Toronto, Multiplex Housing). Council permitted multiplexes of up to four units city-wide in May 2023 through By-law 474-2023, and in June 2025 it adopted a further round of changes for duplexes to fourplexes (By-law 648-2025) and permissions for fiveplexes and sixplexes in Toronto and East York and the northern part of Scarborough that makes up Ward 23 (By-law 654-2025) (City of Toronto, By-law 654-2025).

You can convert an existing house, add to it, or demolish and build new. The City’s monitoring of the first 18 months found 452 multiplex permits issued, and 75% of them were for renovations, conversions or additions rather than new buildings (City Planning presentation to the Planning and Housing Committee, June 12, 2025).

Sources for the table: the City’s considerations when building multiplexes, By-law 654-2025, By-law 648-2025 and the City’s multiplex monitoring final report of May 29, 2025.

Fourplex rules across the city

The multiplex rules borrow the built form of a detached house in the same zone. Height is measured in metres, and where the zone allows less than 10 m, a multiplex gets 10 m so a third storey works. Setbacks are the same as for any other residential building in the zone. The floor space index limit (the “d” number in a zone label) doesn’t apply to multiplexes.

The June 2025 by-law added a cap on bedrooms in all five residential zones. A building with three or more units can have three times as many bedrooms as units, so twelve across a fourplex however you split them, with a bachelor counted as one. A duplex gets four per unit (By-law 648-2025).

Where sixplexes are allowed

Five and six units are permitted in the Toronto and East York district, as its boundary stood on June 26, 2025, and in the area bounded by Steeles Avenue, Neilson Road and the Rouge River, Highway 401 and Midland Avenue. Staff had studied permitting them city-wide (multiplex monitoring final report, May 29, 2025); Council limited them to these areas in June 2025. A fiveplex or sixplex has to be a detached building on one lot, and no part of a semi-detached house or townhouse can be converted to one. Check the City’s multiplex page before you buy on the strength of a sixth unit.

A fiveplex or sixplex can go to 10.5 m if its lowest level is partly raised. The bottom of that level’s ceiling joists has to sit between 1.0 and 1.5 m above grade, with at least 2.4 m of headroom, both over 80% of the floor, and the level has to contain a dwelling unit.

Rules that can still catch you

Two things override the general multiplex rules. The first is Chapter 900 exceptions: site- or area-specific rules in the zoning by-law that are often stricter than the multiplex standards and prevail where they conflict. Of 290 multiplex variance applications the City reviewed, 40 involved one of these exceptions (multiplex monitoring final report). The second is the City’s tree rules: any work that could injure or remove a tree 30 cm or more in diameter on private property needs a permit under the Tree Protection By-law (City of Toronto, considerations when building multiplexes).

Is your lot a multiplex candidate?

Before you buy or spend on design, work through this list.

1. Zone and exceptions. Find the zone label on the City’s interactive zoning map and check for a Chapter 900 exception. A multiplex needs an R, RD, RS, RT or RM zone.
2. Lot width and depth. Width decides how much of the side yard setbacks you lose and whether a side entrance or walkway fits. Depth decides whether you get the 19 m building depth.
3. What’s there now. Converting a house you can keep is usually a different budget from building new. A sound existing structure and foundation can carry three or four units; a tired one becomes a demolition.
4. Trees. A large tree on your lot, a neighbour’s lot or the City boulevard can fix where the building and its foundations go. Have an arborist look early.
5. Water and sewer. A fourplex may need a larger water service than a house. The permit review checks that there’s a sewer to connect to, not its capacity, though the City has flagged wet-weather capacity where multiplexes cluster on combined sewers.
6. Hydro. Toronto Hydro expects most fourplexes to need a 400-amp service, which is currently delivered underground only (multiplex monitoring final report). Loads above 400 amps usually need a transformer on your property. Meters need a metre of clearance, which on a tight side yard often pushes them to the front wall. The City recommends talking to Toronto Hydro early.
7. Heritage and ravines. A property on the heritage register or within a heritage district, or within the ravine protection area, carries its own approvals. Within 300 metres of a railway or 120 metres of a ravine or other water feature, the City can also require site plan approval; our guide to site plan control in Ontario explains when. Where site plan does apply, so does the Toronto Green Standard checklist.
8. Tenants. If the house has tenants and the work needs them to move out, Toronto’s Rental Renovation Licence By-law applies (more below).
9. Semi-detached lots. Converting one half of a semi to a multiplex is permitted, but the City found new semi-detached multiplexes with five or more units across both halves going to the Committee of Adjustment. Expect more process.

The cheapest way to test a lot is a zoning review before you design in detail. The City’s Zoning Applicable Law Certificate includes up to three reviews and in 2026 costs $644.38 for a new house of up to two units or a conversion of or addition to a house, $888.14 for other buildings up to 300 m² and $1,863.82 above that (City of Toronto, Zoning Applicable Law Certificate). Ask the City which category your project falls into when you apply.

As of right or a Committee of Adjustment variance

Most multiplexes go straight to a building permit. Of the 222 multiplex permits the City reviewed in detail, 90% proceeded without a minor variance; the 10% that did were mostly asking for a narrower side yard setback and the platform encroachments that go with it. Height variances, where they came up, were between 0.2 m and 1 m (City of Toronto, multiplex monitoring final report).

Variance activity has grown since. Of 290 minor variance applications for duplexes, triplexes and fourplexes between May 2023 and April 2025, 72% were approved, 10% refused and 18% were still under review or deferred.

A variance is worth it when the relief is small and buys a usable third floor or a fourth unit. It adds its own fee, notice period, hearing and 20-day appeal window. For a fourplex, on our reading of the 2026 schedule, the fee falls in the “all other” category at $6,485.59, because the lower rates are for dwellings with three units or fewer (City of Toronto, Committee of Adjustment fees). Province-wide, a 2025 change also lets you build up to 10% into a required setback without a variance on urban residential land outside the Greenbelt, with some exclusions, which can close the gap on an older lot (Environmental Registry of Ontario, 025-0463, decision November 24, 2025). Our guide to the Committee of Adjustment in Toronto covers the four tests, the fees and the timing in full.

Ask your designer for the scheme with no variances first, then for what each variance would add, and decide from there whether the hearing is worth the time.

Who designs and builds a multiplex

Part 9 or Part 3 of the Building Code

The Ontario Building Code sorts buildings by size. A residential building of three storeys or fewer with a building area (its footprint) of 600 m² or less is a Part 9 building, the same part of the Code that covers houses. Larger or taller buildings fall under Part 3, which brings in more demanding fire protection, exits and, in practice, elevators. Ontario’s current Building Code is the National Building Code 2020 as amended for Ontario, adopted by O. Reg. 163/24.

Almost every multiplex is a Part 9 building. The City’s monitoring saw a single four-storey multiplex in its permit data, and industry told the City that elevators and the other Part 3 rules make four storeys hard to justify on cost and layout.

Within Part 9, a multiplex is still more than a house: fire separations between units, separate exits, sound separation, and limits on windows close to a side lot line all shape the design. A narrow lot with a 0.9 m side yard can lose windows on that wall for fire reasons, which is worth knowing before you plan bedrooms there.

Architect, BCIN designer or Licensed Technologist

Who can legally design your multiplex depends on its gross area, which under the Architects Act is the total area of all floors above grade.

A three-storey fourplex with a 200 m² footprint is already at 600 m² above grade; a basement fully below grade doesn’t count. A slightly larger building needs an architect or a Licensed Technologist OAA, so measure the gross area before you hire.

You’ll also need a structural engineer (almost always on a conversion), a mechanical designer, a surveyor and often an arborist.

Toronto’s pre-approved multiplex plans

The City now offers free pre-approved plans for four-unit and six-unit multiplexes, in narrow and wide versions, designed by LGA Architectural Partners. The fourplex comes with electric, gas or hybrid heating and the sixplex with electric or hybrid (City of Toronto, Pre-Approved Multiplex Building Plans). Permit fees still apply, changing the plan takes it out of the pre-approval, and you still need design professionals for grading, foundations, structure and mechanical systems. On a lot that suits one of the designs, they can shorten design and review; on one that doesn’t, a design made for your lot will usually serve you better.

The builder, and who runs the project

Multiplexes are mostly built by small and mid-sized residential builders. You can hire one on a fixed price once the drawings are complete, or earlier on a cost-plus or design-build basis. Our article on the budget that matters most explains why the price you approve at the start shapes everything after it, whichever route you take.

Owners often leave open who runs the project on their side. On a multiplex you are the developer: you hold the land, the loan, the permits and the schedule, and the builder, the designer, the lender and the City all come to you for decisions. Decide before you sign anything whether you’ll do that yourself, hand it to a design-build contractor or hire someone independent.

The multiplex development budget

A builder’s quote covers construction; your budget also has to carry the land, the soft costs and the financing. We don’t publish a per-unit construction cost, because no current public source for Toronto multiplexes stands up and a conversion and a new build are far apart. What follows is the outline, with the government charges that can be priced exactly.

The four parts of the budget

Government charges, priced

• Development charges. Toronto charges none on the second, third or fourth unit, and since By-law 845-2025 the fifth and sixth are reduced to $0, provided there are no more than six units on the lot (City of Toronto, By-law 845-2025). The first unit is the one that isn’t exempt; on a conversion that unit is the existing house. Where you’re replacing an existing house, the by-law credits the charge for the demolished unit if the demolition permit was issued within 60 months before your complete building permit application (Toronto Municipal Code, Chapter 415). Keep the dates in mind if the house comes down long before you apply.
• Parkland. The second to sixth units are exempt from parkland dedication, or up to seven units where one is a garden or laneway suite. Council set this in July 2025 and corrected the wording in March 2026 (City of Toronto, By-law 269-2026).
• Education development charge. This one is the Toronto Catholic District School Board’s, under its own by-law, and the City’s exemptions don’t speak to it. The rate is $3,893 per unit to December 2, 2026 and $4,193 from December 3 (City of Toronto, Education Development Charges). Ask the examiner how it applies to your units.
• Building permit. In 2026, $18.56 per square metre of new residential floor area plus $56.33 for each new unit (City of Toronto, Building Permit Fees). As an illustration only, a 400 m² fourplex would be about $7,650 before plumbing, HVAC and other permit lines.
• Variance. $6,485.59 if you need one, plus the cost of a planner and drawings for the hearing.
• Tenants. If the work requires an existing tenant to move out, you need a Rental Renovation Licence. The by-law has been enforced since July 31, 2025, the fee is $728 per unit in 2026, and you must apply within seven days of serving the N13 notice. You must also offer temporary housing or rent-gap payments, and a moving allowance of $1,500 or $2,500 depending on unit size (City of Toronto, Rental Renovation Licence, Information for Landlords). The Residential Tenancies Act sets its own notice and compensation rules alongside. Talk to a lawyer before you serve anything.

The garden or laneway suite question

Applying for a fourplex and a garden or laneway suite at once used to risk charges on all five units. Since July 2025 a garden or laneway suite under the City’s development charge deferral program doesn’t count toward the unit total (By-law 845-2025). If you’re weighing the suite separately, our guides to garden suite costs in Toronto and laneway houses cover it.

HST: the line owners miss

If you build or substantially renovate a residential building and rent it out, the Excise Tax Act treats you as a builder who has sold the building to yourself at fair market value when the first tenant moves in, and HST is due on that value. The Canada Revenue Agency calls this a self-supply (CRA, Residential Real Property: Deemed Supplies).

The rebates are the other side of it. The federal purpose-built rental rebate returns 100% of the GST (the federal part of HST) on a new building with at least four units, each with a private kitchen, bathroom and living area, where at least 90% are held for long-term rent, if construction begins after September 13, 2023 and before 2031 and finishes before 2036 (CRA, Purpose-built Rental Housing Rebate). Ontario offers a matching 8% provincial rebate for qualifying projects that start between September 14, 2023 and the end of 2030 and finish by the end of 2035 (Ontario, Building More Homes Faster). A new fourplex can qualify; a triplex can’t. The CRA lists the substantial renovation of an existing residential building as ineligible, so converting a house generally won’t qualify even where the self-supply rule applies. Bring an accountant in at the feasibility stage.

Selling the units instead

Most multiplexes in Toronto are rentals. To sell units instead, you need to be licensed as a builder with the Home Construction Regulatory Authority and enrol the homes with Tarion before construction starts (Tarion, Qualification for Enrolment process), and to sell units separately the building has to be registered as a condominium. The City’s monitoring report noted that industry stakeholders put the cost of registering a multiplex condominium at over $80,000. Decide before design, because it changes the lender, the tax position and the drawings.

Financing and contingency

A fourplex is usually financed as a residential property of up to four units. At five units and up, CMHC’s multi-unit programs such as MLI Select come into the picture, which the City’s monitoring report names as a reason the fifth unit matters to financing. Our guide to construction financing in Ontario covers how draws, holdback and a lender’s cost review work. A conversion of an old house needs a larger contingency than a new build, because more is unknown until the walls are open; our article on how much contingency is enough sets out how to size it.

For the income side, the City’s 2025 report found multiplex units renting at an average of $2.93 per square foot, from listings and owner data gathered between 2023 and 2025. Use it as a starting point and test it against rents on your own street.

The multiplex schedule from idea to tenants

A simple conversion and a new build with a variance take very different times, so we give the phases rather than one number:

1. Feasibility. Zoning review, survey, arborist, a first read on servicing and hydro, and a budget with every line above in it. Time spent here is usually the cheapest time on the project.
2. Design. Concept, then permit drawings, structural and mechanical design. The pre-approved City plans can shorten this if your lot fits one.
3. Committee of Adjustment, if needed. The City reported complete applications reaching a hearing in under six weeks in 2025 (City of Toronto, May 28, 2026 report), and there is a 20-day appeal period after the decision. Add the time to prepare a complete application.
4. Tenants, if any. The Rental Renovation Licence needs a building permit in hand, so this runs after design and permit, not before.
5. Building permit. Review time depends on how complete the application is. Every round of examiner comments adds time.
6. Pricing and contract. If you’re tendering on complete drawings, allow time for builders to price and for you to compare quotes on the same basis. Our guide to reading a construction estimate helps here.
7. Utilities. Apply for the water service and the hydro connection early, because their timing is set by Toronto Water and Toronto Hydro.
8. Construction. Demolition or strip-out, foundations or underpinning, structure, envelope, services, finishes and inspections.
9. Occupancy and lease-up. Final inspections, then tenants. Interest on the construction loan keeps running until the units are leased.

As on larger projects, most of a fourplex’s schedule risk sits in the approvals and decisions before construction starts. Our article on what developers get wrong about schedules covers how to plan for it.

Frequently asked questions

What is a multiplex in Toronto?

A residential building on one lot with two to six dwelling units, at least one of them partly or entirely above another. A house with a secondary suite is not a multiplex under the by-law.

Where are sixplexes allowed in Toronto?

In the Toronto and East York district as its boundary stood on June 26, 2025, and in the Ward 23 area of Scarborough set out in By-law 654-2025. Fourplexes are allowed city-wide. The areas may widen, so check the City’s multiplex page before you buy.

Do you pay development charges on a fourplex in Toronto?

Not on the second to sixth units, as long as there are no more than six on the lot. The first unit isn’t exempt, but where you replace an existing house, a demolition permit issued within 60 months before your complete permit application earns a credit. The school board’s education charge is separate.

Do I need an architect to build a fourplex?

If the building is over three storeys or exceeds 600 m² of gross area above grade, you need an architect, or a Licensed Technologist OAA within that licence’s limits of four storeys and 600 m² of building area. Below that, a designer qualified under the Building Code in the Small Buildings category, a Licensed Technologist OAA, an architect or an engineer can generally design it.

Can I build a fourplex and a garden suite on the same lot?

Yes. A suite under the City’s development charge deferral program doesn’t count toward the six-unit total for the charge exemption, and parkland is exempt for up to seven units where one is a garden or laneway suite.

Where to start

The first spend should go on the lot rather than the drawings. A zoning review, a survey, the trees, the servicing and a budget that names every line, including HST and the first unit’s charges, will tell you whether the project works before you’ve spent much. Then pick the team and decide who runs the project on your side.

We haven’t delivered a multiplex as a firm. Our 20+ years and $3B+ of delivered work were built at PCL Constructors and Oxford Properties on larger residential, office, retail and industrial projects, and the same disciplines carry over to a fourplex. The budget is built line by line, approvals are planned as their own phase, quotes are compared on the same basis, and someone tracks cost and schedule through the build. If you’re weighing a multiplex and want an experienced hand on the feasibility, the budget and the team, our development management service is where to start.