The missing-middle movement is still reshaping Toronto's housing landscape, and the rules have moved a lot in the last two years. Fourplexes are now permitted as-of-right on essentially every residential lot in the city, development charges have been waived on small multiplexes, parking minimums are gone, and the federal and provincial governments have eliminated HST on qualifying new purpose-built rentals. For investors who want real cash flow instead of a condo that bleeds every month, one strategy keeps standing out: buy a lot, build a four-plex in the main building, and add a garden or laneway suite to reach five units.
Five units is the magic number. At five-plus units a property qualifies for commercial financing through CMHC's MLI Select program — up to 95% loan-to-cost, amortizations stretching to 50 years, and a 1.10 debt-service-coverage requirement that, done correctly, produces positive cash flow while leaning less on personal credit. Built right, a project like this can return most of your initial capital and leave you holding a high-value, cash-flowing asset, with the same capital recyclable into the next deal.
I'm building one of these myself right now in Toronto, so this is written from the inside. Here's what actually matters when you're hunting for the property.
1. Start with the zoning — but know what's changed
Zoning is the foundation, and the foundation shifted under everyone's feet recently. As of May 2023, Toronto permits up to four self-contained units as-of-right on virtually all Neighbourhood-designated residential lots — no rezoning, no Committee of Adjustment for a compliant design. In June 2025 the city went further and allowed five- and six-unit "detached houseplexes" as-of-right, but only in the Toronto & East York district and Ward 23 (Scarborough North). Everywhere else stays capped at four units in the main building for now.
That four-versus-six distinction matters more than it looks, and I'll come back to it, because it's the reason the 4+1 format exists.
For ranking sites, the old priority order still holds, but there's an important massing reason RM stands out:
- Commercial or higher — best for maximizing density and value.
- RM (Residential Multiple) — my preferred target. Beyond flexibility for multi-unit work, RM generally lets you push for a bigger main building and, crucially, a full-size top floor — a clean box rather than a clipped one.
- R (Residential) — workable for a four-plex, but subject to the main-wall-height rule below.
- RD / RS (Residential Detached / Semi-Detached) — permitted, with the tightest performance standards.
Here's the massing nuance that drives the ranking. In the lower zones (R, RS, RD), the by-law caps the main wall height separately from overall building height — so a flat-roofed top storey is only allowed if it's stepped back (roughly 1.4 m) from the walls below, or tucked under a sloped roof. Either way, you lose floor area on the top unit, exactly where you'd otherwise have a full-size three-bedroom. RM is more forgiving and lets that top floor run closer to full size, which is why a deal in RM often pencils where the same lot in RD wouldn't. Always have your architect confirm the main-wall and step-back rules for the specific zone before you bank on the top-floor area.
There's a bigger version of this play in the sixplex zone. In the eight Toronto–East York district wards plus Ward 23 (Scarborough North) — the only parts of the city where five- and six-unit buildings are as-of-right — you can now build a sixplex in the main building and add a garden or laneway suite behind it, for seven units total (a "6+1"). The suite doesn't count against the six-unit main-building maximum; it's additional. That's a meaningful jump in scale and income on a single lot.
The catch is land. Seven units only works on a genuinely large lot — a sixplex footprint eats most of the buildable area, and if you try to force a 6+1 onto a tight lot, your unit sizes collapse to the point where the deal stops making sense. The 6+1 is a big-lot strategy; the 4+1 is the workhorse that fits far more properties. Match the format to the lot, not the other way around.
Two financial tailwinds are easy to miss. Development charges are fully waived on multiplexes up to six units, which saves roughly $200,000–$270,000 versus the pre-reform regime; if you go to seven units with a suite, the charge on that extra unit can be deferred and is forgiven if you hold it as a rental for 20 years. And parking minimums have been eliminated citywide, so you are no longer forced to surrender buildable area to a parking pad.
Pro tip: confirm the exact permissions on the City of Toronto Zoning By-law interactive map before you write anything, and treat the map as a starting point, not gospel — it doesn't always reflect the newest amendments or Ontario Land Tribunal decisions.
2. Target deeper lots — the 118-foot rule
Frontage gets all the attention, but on these projects depth is what makes or breaks the deal.
Look for a minimum 25 ft frontage, and prioritize lot depth of 118 ft or more. Here's the mechanics behind that number. Toronto's by-law sets a default maximum building depth of roughly 17 metres (about 55 ft). For a multiplex you're allowed to extend that to 19 metres (about 62 ft) — but to actually use the deeper building and fit a garden suite behind it, you have to stack the main building, the required separation distance between the house and the suite (4 m if the suite is single-storey and 4 m or under in height, 7.5 m if it's a true two-storey suite), the suite itself, and the rear-yard setback, all within the lot depth.
On a lot shallower than about 118 ft, that math doesn't close. You get squeezed back down to a 55 ft main building, which directly shrinks your buildable area, shrinks the units, and weakens your rents. I've seen otherwise-good deals fail to pencil out for that single reason. Run the layout against the actual depth before you fall in love with a property, and get your architect to confirm it lot by lot — the 118 ft figure is a screening floor, not a guarantee.
I specifically prefer properties with a laneway behind them. Laneway suites get better setbacks than garden suites — you can build closer to the rear lot line and, in many side conditions, right up to the side line where there are no openings — which means a larger suite and a higher rent. Just as important, a lane lets you give the suite its own separate entrance and exit off the laneway, completely independent of the main building. That privacy and separation make the unit more attractive to tenants and easier to manage.
That points to the real objective on every one of these projects: maximize unit size. The goal isn't to cram in the most doors — it's to build units people actually want to live in. I target three-bedroom, two-bathroom units of around 1,000 square feet wherever the lot allows. Units at that size hold their value, command premium rents, and appraise stronger, which feeds straight back into the value of the whole building. People want livable space, and that's the entire point of building these — tiny, awkward units undercut both your rent roll and your exit. Depth is what gives you the room to hit that target, which is exactly why the 118 ft floor matters.
3. Check fire access early — it's the quiet deal-killer
Fire access is the requirement that quietly sinks more garden- and laneway-suite projects than any other. For a garden suite, you need a clear, code-compliant path from the public street to the suite entrance with a maximum travel distance of about 45 metres. For a laneway suite, the path can run up to 90 metres where access is via the lane, provided additional fire-safety measures acceptable to the City are in place. Hydrant proximity and the firefighting-vehicle parking location feed into this too.
Some lots satisfy every other rule and fail here. Confirm fire access before you close, not after.
4. Watch for protected trees — the other instant deal-killer
Trees kill more backyard-suite projects than almost anything except fire access, and people consistently underestimate them. Under Toronto's Private Tree By-law (Chapter 813), any tree on private property measuring 30 cm or more in diameter at breast height — that's the trunk diameter measured at 1.4 m (about 4.5 ft) above the ground, not at the middle of the trunk — is protected. You need a City permit to remove or even injure it, an arborist report to apply, and the review takes weeks; removing one without a permit carries fines up to $100,000 per tree plus mandatory replanting.
Here's why it matters for this strategy specifically. If a large protected tree sits exactly where the garden suite would go, your project can be dead on arrival — the City will often refuse removal, and you can't build the suite around it. A tree in the footprint of the main building is a different story: it's generally easier to get approval to remove or work around a tree in the way of the principal dwelling than one in the way of an ancillary suite, because the main building has stronger standing as a permitted use. But none of this is something to assume. Walk the lot, find the big trees, and confirm their status and your options with Urban Forestry before you commit — a single mature tree in the wrong spot can take the whole deal off the table.
5. Buy for the land — not the building
This is where my thinking has changed.
I used to look for properties with an existing legal basement apartment or duplex zoning, on the theory that separate entrances, fire separations, and parking were already in place and a renovation would be cheaper than a rebuild. I no longer underwrite that way.
If your plan is a four-plex plus a suite, you're going to take the existing house down to nothing and start from zero anyway. So the existing structure has essentially no value to you — you should be buying at land value, full stop. Paying a premium for a house you're going to demolish is paying for something you're throwing away.
The deeper reason to favour a new build over a major renovation is tax. A newly constructed purpose-built rental with four or more units qualifies for the enhanced HST rebate: 100% of the federal 5% with no fair-market-value cap, and — under Ontario's 2026 HST relief for purpose-built rentals — the provincial 8% as well, for projects whose construction begins between April 1, 2026 and March 31, 2027 and is substantially complete by the end of 2029. On a qualifying new build, that's effectively the full 13% HST eliminated.
A substantial renovation gets none of that. The enhanced rebate explicitly excludes substantial renovations of existing residential complexes. Worse, a substantial renovation triggers the self-supply rules, meaning you have to self-assess HST on the fair market value of the finished property, and you're left with only the old new-residential-rental rebate — which is capped, phases out above a $350,000 unit value, and disappears entirely at $450,000. In Toronto, every unit blows past those thresholds, so the rebate is effectively zero.
Put it together and the renovation path is a trap: the HST you can't recover, plus the cost overruns and surprises that come with fixing an old structure, push your all-in number close to a new build — but you end up with a renovated property that appraises lower and appreciates less. New construction appraises higher (cap-rate treatment of new, purpose-built product is more favourable), captures the full rebate, and gives you a clean 50-year asset. The land-value purchase plus new build wins on almost every line.
Note the four-unit threshold for the federal rebate: a four-plex is the smallest building that qualifies on its own. The garden suite then adds your fifth unit for CMHC. The two requirements line up neatly.
6. Structure the deal around CMHC MLI Select — and watch the 2026 changes
MLI Select is the engine that makes this strategy work, and it's been moving. Here's the current state of play.
To unlock the best terms, a project must earn points across affordability, energy efficiency, and accessibility — and as of the June 2024 update you can no longer reach the top tier through energy efficiency alone. Energy efficiency now caps at 50 points, so reaching higher tiers means combining pathways. In Toronto, affordability and accessibility points are hard to capture in practice, so most multiplex projects lean on energy — and that's exactly where the bar just moved.
Highlight — the energy targets got much harder for new construction. Effective November 28, 2025 (with a transition window letting you qualify under the old criteria until September 30, 2026), CMHC now scores new builds against the 2020 codes: the 2020 NBC Part 9 for low-rise residential like a 4+1, and the 2020 NECB Part 3 for mid- and high-rise. The points are measured as a percentage improvement over the code's Tier 1 baseline. For low-rise (NBC Part 9), the tiers are roughly: 20% better for Level 1 (20 points), 40% better for Level 2 (35 points), and 70% better for Level 3 (50 points) — the full energy score. (Mid/high-rise under NECB Part 3 runs 25% / 50% / 60% for the same point levels.) In other words, the old "40% better than code" that used to earn the top energy points now only gets you partway; hitting the 50-point energy max on a low-rise build now means roughly 70% better than the 2020 baseline, which is near-net-zero territory and a real cost and design conversation. Get an energy modeller involved at the design stage, and if 50 energy points isn't realistic for the lot, plan to make up the difference through affordability or accessibility points to clear the 50-point program minimum.
The mechanics most people care about: your point tier drives the benefits — 50 points unlocks the program and a premium discount, 70 points adds a longer amortization, and 100 points reaches the maximum 50-year amortization, all against a 1.10 debt-service-coverage ratio (for every $100 of expenses the property must generate at least $110 of income). You can lock 5- or 10-year terms priced off the Canada bond, the mortgages are assumable, and pari passu (equal-ranking) registrations are allowed. Note too that CMHC raised premiums in 2025, adding a surcharge for each five-year stretch of amortization beyond 25 years — so longer amortization costs more up front than it used to. Model it.
On eligibility, remember CMHC's structure for what counts as a qualifying multi-unit property: either one connected building with five or more units, or one legal lot with a combination of dwellings of similar characteristics totalling five or more units. The 4+1 falls under the second category. "Similar characteristics" has historically meant similar scope, age, and quality, and since you're building both the four-plex and the suite new and at the same time, you're well positioned — but get your lender to confirm the file before you commit.
Heads-up on a 2026 change to confirm with your lender. I'm hearing that, effective June 8, 2026, CMHC is updating the operating-expense benchmarks on MLI Select applications, with two practical effects at a high level: higher required maintenance reserves, and higher required management fees. CMHC has reset these benchmarks before (it did so effective June 19, 2023), so this is consistent with how the program is administered. Both changes raise your underwritten expenses, which lowers NOI and therefore the loan CMHC will support — so it can shrink your maximum financing on the same building. Confirm the exact effective date and figures with your CMHC lender and broker, and re-run your sizing under the new benchmarks before you firm up.
And the standing advice that never changes: always model your financials with and without MLI Select. If the program tightens or your application stalls, you need a deal that still works on conventional terms.
7. Plan utility and servicing capacity — and design for fallback
A four-plex plus a suite draws far more power than a single-family home, and the electrical service is where servicing timelines quietly wreck schedules. In practice, the most convenient path is often a 200-amp service paired with gas, because it avoids the worst of the utility queue. Stepping up to 400 amps can mean a wait of several months and meaningful cost; going to 600 amps for a fully all-electric build can stretch into a far longer wait and a much bigger bill. Those lead times and costs move around, so confirm them with Toronto Hydro for your specific address early.
The practical move is to have your architect and electrical consultant design around fallback options from the start — lay out the building so it works at 200 amps with gas if the higher service can't be delivered on your timeline, while leaving a clean path to upgrade. That way a servicing delay doesn't force a redesign late in the process. Just weigh it against the energy-points side of the equation: gas can ease the electrical constraint, but all-electric heat pumps are usually how you reach the higher energy tiers under the tougher 2020 criteria, so model both the service cost and the points impact before you lock the mechanical design.
8. Buy where densification is already happening
High-growth, transit-served neighbourhoods deliver the best risk-adjusted returns. East York, parts of Scarborough, and pockets of Etobicoke are strong for infill. If the budget allows, southern locations closer to the lake — around High Park, for example — command higher rents and stronger appreciation. Stay away from areas with weak rental demand; thin demand undermines both your lease-up and your long-term value.
Why the 4+1 is the smart entry point
Here's the case for this specific format over anything bigger or smaller.
It's not too small. Spreading income across five units means no single vacancy guts your cash flow — one empty unit is a fifth of the building, not half of a duplex. That diversification is what makes the numbers stable enough to underwrite confidently.
It's not too big. A five-unit project stays in the manageable zone for a first-time developer: the construction is conventional residential framing and trades, the financing fits cleanly inside MLI Select, and you're not stepping into the cost, complexity, and timeline of mid-rise. It's a realistic first project for someone serious but new to ground-up development.
And it's deliberately engineered around the rules. Fourplexes are as-of-right on virtually every residential lot in the city, and a garden or laneway suite can be added on top almost anywhere a lot physically qualifies — so the 4+1 reaches CMHC's five-unit minimum on the widest possible range of properties. A four-unit main building qualifies for the HST rebate on its own, and the suite gets you to five for financing. The 6+1 reaches seven units and more income, but only in the eight sixplex wards and only on a large enough lot to keep the units livable; outside those wards, or on a normal lot, the 4+1 is the format that actually fits. It threads every rule — units, financing, and tax — on the most properties.
It also leaves room to be creative. The suite can be a premium two-storey laneway unit, a multi-generational space, or a higher-rent standalone; the main building can be tuned for unit mix and energy points; and the whole package can be held, refinanced, or sold as a stabilized five-unit asset. Few strategies give a newer investor this much optionality at this scale.
The real edge, though, comes from repetition. Once you've found a configuration that works — a lot size and shape, a floor plan, a unit mix, a finish package, a lender, a set of trades — the goal is to run it again. Development is risky and slow the first time precisely because everything is new. The second and third deals get faster, cheaper, and more predictable when you're reusing what you already proved out instead of reinventing it each time. Find the formula that pencils, then repeat it. That's how a single project becomes a portfolio.
Final thoughts
A four-plex with a garden suite remains one of the most profitable and scalable residential strategies in Toronto, and the 2026 rule environment — as-of-right fourplexes, waived development charges, no parking minimums, and full HST relief on qualifying new builds — has only sharpened the case. Buy for the land, build new, structure around MLI Select with eyes open to the 2026 benchmark changes, and you can build a high-yielding portfolio while adding real housing to the city.
If you're looking for the right property to start a project like this, this is exactly what I do — I specialize in missing-middle housing and I'm building a 4+1 in Toronto right now. Let's connect and find the opportunities that pencil out.
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Disclaimer: This reflects my experience and current understanding of the rules as of 2026; programs and by-laws change. Always confirm zoning, fire access, financing, and tax treatment with the appropriate professionals before making any investment decision.
