The Toronto Multiplex Feasibility Study: A Complete Guide

The Toronto Multiplex Feasibility Study: A Complete Guide

A Toronto multiplex feasibility study is a go or no-go test built from five inputs: how many units the zoning allows, what construction will cost, and what the units will rent or sell for, weighed against the financing the deal can support and the contingency the numbers can absorb. Two lots that look almost identical on a zoning map can land on very different numbers once those five inputs run through a pro forma. This piece runs the same test on a 25-foot infill lot and a 40-foot corner lot to show how much the margin can move, even when both clear the bar.

What a Feasibility Study Is, and Isn't

A feasibility study is not a full set of construction drawings, and it isn't a formal cost estimate from a contractor. It's the test that decides whether either is worth commissioning at all. TESA's short feasibility study explainer covers the baseline definition; this piece runs the full five-input test against two contrasting lots so the framework is visible in practice.

The Five Inputs That Decide Go or No-Go

1. Zoning capacity. How many units, what height, and what footprint the lot's zone actually allows once setbacks are applied. Toronto's Zoning By-law 569-2013 governs this for every residential zone, including the multiplex-permitting Neighbourhoods zones, and it's the only input that's genuinely binary: either the units fit, or they don't.
2. Hard costs. The actual construction spend. Industry estimates put custom Toronto/GTA low-rise builds at roughly $350 to $900+ per square foot in 2026, with soft costs (design, engineering, permits, surveys, legal, financing) adding another $25 to $55 per square foot. These are contractor-marketing ranges, not a government price index, so a commissioned estimate is what actually locks a number.
3. Revenue. Achievable rent or resale value for the finished units, tested against comparable listings for the specific block and unit size, not a citywide average.
4. Financing. What a lender will actually put behind the numbers: loan-to-value, amortization, and the debt service the rents have to cover.
5. Contingency. The buffer that absorbs the gap between the estimate and the tender price, sized to the lot's own risk: site conditions, party wall exposure, soil.

Miss any one of the five and the other four are just an exercise. A study that skips zoning capacity is pricing units that might not be legal. A study that skips financing is underwriting a deal no lender will actually fund.

Two Lots, One Test: A 25-Foot Infill Lot vs a 40-Foot Corner Lot

Both examples assume the owner already holds the lot, the common case for the small investor and wide-lot homeowner this framework serves, so the numbers price construction only, not land acquisition. Every figure is an illustrative planning number TESA uses to demonstrate the method, not a quote for any specific address.

Lot A: The 25-Foot Infill Lot

Frontage: 25 ft (7.6 m), a typical narrow infill parcel in a Neighbourhoods zone. A fourplex is permitted as-of-right, and multiplexes carry no on-site parking requirement, which matters on a lot this narrow. Side and rear setbacks (illustrative ranges of roughly 0.9 to 1.2 m per side, 7.5 m rear, unverified for any specific zone) chew hard into a 25-ft frontage, leaving a tight buildable envelope of around 2,500 sq ft across four units. Three storeys fit under the 10-metre height standard.

Narrow-lot construction (tighter equipment access, more shoring, shared party walls) is priced here at $300/sq ft hard, plus $45/sq ft soft. That prices construction, including a 10% contingency, at roughly $950,000. At 85% loan-to-cost, above the conventional 65-75% range, the loan is about $806,000. At 4.5%, 40-year amortization, with Canadian mortgages compounding semi-annually rather than monthly, annual debt service runs about $43,200.

Four small units (about 625 sq ft each) renting at an assumed $2,600/month clear roughly $124,800/year in gross rent, or about $93,600 in net operating income (NOI) after a 25% expense allowance.

Verdict: Go. DSCR comes in at 2.17x, cash-on-cash at about 35%. Break-even rent to hit a lender's 1.25x DSCR target sits at roughly $1,500/unit/month, comfortably below the assumed $2,600. The catch is leverage: 85% loan-to-cost sits above what a conventional lender typically extends on a four-unit building, so the verdict still depends on finding financing at that level.

Lot B: The 40-Foot Corner Lot

Frontage: 40 ft (12.2 m), enough width that the same setback rules leave a materially larger buildable envelope: about 4,200 sq ft across four units. Three storeys fit under the same 10-metre standard. The wider, more efficient floor plate brings cost down to roughly $280/sq ft hard, $35/sq ft soft. Total construction, with a 10% contingency, comes to about $1.46 million.

At 85% loan-to-cost, above the conventional 65-75% range, the loan is about $1,237,000. At 4.5%, 40-year amortization, with Canadian mortgages compounding semi-annually rather than monthly, annual debt service runs about $66,300.

Four larger units (about 1,050 sq ft each) at an assumed $3,750/month clear $180,000/year in gross rent, or about $135,000 in NOI after a 25% expense allowance.

Verdict: Go. DSCR lands at about 2.04x, cash-on-cash at roughly 31%. That clears even the higher 1.20-1.30x band conventional multi-unit lenders quote, a comfortable go rather than a marginal one, though it carries the same above-conventional 85% loan-to-cost caveat as Lot A.

Reading the Two Pro Formas Side by Side

Metric	Lot A (25-ft infill)	Lot B (40-ft corner)
Buildable area	~2,500 sq ft	~4,200 sq ft
Construction cost (incl. 10% contingency)	~$950,000	~$1.46M
Loan	~$806,000	~$1,237,000
Annual debt service (4.5%, 40-yr, semi-annual compounding)	~$43,200	~$66,300
Gross rent	~$124,800/yr	~$180,000/yr
Net operating income	~$93,600/yr	~$135,000/yr
DSCR	2.17x	2.04x
Cash-on-cash return	~35%	~31%
Verdict	Go	Go

Same lot depth, same zoning tool, same leverage assumption. The extra 15 feet of frontage doesn't flip the verdict here, but it widens the margin considerably.

Why Zoning Capacity Gets Settled Before Anyone Draws a Line

Toronto's zoning by-law defines a multiplex as a residential building of two to four units (duplex, triplex, fourplex), with at least one unit sitting fully or partly above another. Since a May 10, 2023 Official Plan and Zoning By-law amendment, multiplexes of up to four units are permitted as-of-right on residential lots citywide, no rezoning required. A June 2025 amendment pushed that to six units as-of-right in the Toronto and East York Community Council area and additional wards, building on an earlier Scarborough North sixplex approval, and a citywide study is now underway to expand six-unit permissions further. Confirm which rule applies to a specific lot before assuming a number.

Height works differently from a typical low-rise zone. Multiplexes are exempt from storey-count limits and maximum floor space index rules, unless a Chapter 900 site-specific exception says otherwise. Height caps at 10 metres even where the applicable Height Overlay shows less; where the overlay permits 10 metres or more, its own limit applies instead. Setbacks follow the same rules as any other residential building in that zone (R, RD, RS, RT, RM), and there's no single citywide number: the figures vary by zone and must be confirmed on the City's Interactive Zoning By-law Map. Industry sources commonly cite illustrative ranges of around 6 m front, 7.5 m rear, and 0.9 to 1.2 m side (rising to about 1.5 m for buildings of five or more units), run through Chapter 10 base standards or Chapter 900 exceptions, but these are typical ranges, not guarantees. Since February 3, 2022, duplexes, triplexes, and fourplexes also carry no on-site parking requirement, part of a broader 2021 Council decision removing most residential parking minimums citywide.

Two fee lines are easy to miss. Toronto's 2026 building permit fee schedule charges $18.56 per square metre of new residential floor area, with a $214.79 minimum fee and $92.79/hour for extra examination and inspection; a Zoning Certificate runs 25% of the total building permit fee. And since July 24, 2025, the second through sixth unit in a development of up to six units is exempt from Toronto's development charges, with only the first unit charged as if it were a single detached home, a real saving on any multiplex that clears zoning capacity.

None of that costs anything to confirm, and all of it changes the buildable envelope the other four inputs get tested against, which is why zoning capacity comes first.

Reading the Pro Forma the Way a Lender Will

Three numbers do the work once a cost estimate is in hand.

• Debt service coverage ratio (DSCR): net operating income divided by annual debt service. Lot A's 2.17x and Lot B's 2.04x both clear a lender's typical 1.20-1.30x target, though Lot A carries more cushion.
• Cash-on-cash return: annual pre-tax cash flow divided by the equity actually invested. Lot A returns about 35%, Lot B about 31% (both helped by 85% leverage); both clear the bar for an investor who wants current yield, not just appreciation.
• Break-even rent: what the achievable rent would need to be for NOI to just clear a lender's DSCR target. Lot A's sits around $1,500/unit/month against an assumed $2,600; Lot B's is about $2,300/unit/month against an assumed $3,750. Both have room, though both depend on financing above the conventional loan-to-cost range at 85% leverage.

Financing narrows fast at this scale. CMHC's MLI Select program, which can push leverage up to 95% loan-to-value and amortization out to 50 years at its top scoring tier, requires a minimum of five rental units per project; a standard four-unit multiplex doesn't qualify and has to go the conventional bank route instead, typically 65-75% loan-to-value at a DSCR of roughly 1.20-1.30x, both market conventions that vary by lender rather than fixed rules. A five- or six-unit building clears MLI Select's unit-count floor and can be scored: 50 points unlocks up to 85% LTV on an existing property (up to 95% loan-to-cost on new construction) and 40-year amortization; 70 points unlocks up to 95% LTV and 45-year amortization; 100 points unlocks up to 95% LTV, 50-year amortization, and limited-recourse financing.

Kill Signals: When the Numbers End the Deal

A feasibility study exists to say no cheaply, before a commissioned estimate turns a bad lot into an expensive lesson. Signals that end a deal at this stage:

• DSCR under 1.0x with no realistic path to a higher achievable rent; no contingency line fixes that.
• Hard costs at $300/sq ft or higher with no efficiency lever left to pull (site access, floor plate shape, party walls), and revenue that doesn't move with it.
• Zoning capacity that comes in lower than assumed once setbacks are plotted, cutting a fourplex to a triplex or worse before a drawing is commissioned.
• Cash-on-cash return that's negative and stays negative once contingency is spent.
• A financing structure that only works at leverage or amortization a lender won't actually approve for that unit count, such as the MLI Select five-unit floor a four-unit building simply can't clear.

Desktop Screen or Commissioned Feasibility Study?

A desktop screen answers the zoning-capacity input alone: unit count, height, setbacks, and parking, pulled from the Zoning By-law and the City's own mapping tools. It's free or close to it, and enough to rule a lot in or out before spending money on anything else, but it doesn't test hard costs, revenue, or financing, so it isn't enough to sign a purchase agreement or price a construction loan against. A commissioned feasibility study prices all five inputs against the specific lot instead: a real cost estimate rather than an industry range, comparable rents or resale prices for that block, and a pro forma built to the DSCR and loan-to-value a specific lender will actually apply. That's the version that belongs in front of a lender or a vendor's lawyer.

How TESA Structures a Feasibility Engagement

TESA Real Estate underwrites the numbers, TESA Development prices the drawings-stage cost estimate, and TESA Capital structures the financing test against actual lender terms, coordinating with the licensed lenders who fund the deal. One group runs all five inputs against the same lot, instead of an owner collecting a zoning opinion, a cost estimate, and a financing quote from three firms that never talk to each other.

What we ask for going in: the lot's legal description or address, its current zoning designation, known site conditions (soil reports, existing structure, easements), and the owner's target, whether that's a rental hold, a sale, or a mix. What comes out is a single go or no-go verdict: buildable unit count and height confirmed against the by-law, a hard and soft cost range priced to the specific lot, achievable rent or resale tested against comparable listings, and a pro forma showing DSCR, cash-on-cash, and break-even rent the way a lender will actually read it.

From there, the next questions are usually what construction costs unit by unit, and what the build sequence looks like from permit to occupancy. Those live in TESA's multiplex cost breakdown and its ground-up development guide.