Duplexes, Multiplexes and Secondary Suites in Ontario: An Investor’s Primer

More Ontario investors are buying buildings with more than one unit. The reason is simple. One purchase can produce two, three, or four rent cheques. The rules in Ontario have also shifted in favour of adding units. If you are a cash buyer looking at off-market deals, it helps to know what these property types are, how the financing works, and where the real margin sits.

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Duplex, Multiplex, Secondary Suite: What Each One Means

The words get used loosely, so here is the plain version.

A duplex is one building split into two self-contained units. Each has its own kitchen, bathroom, and entrance.
A triplex has three units. A fourplex has four. Multiplex is the catch-all term for small multi-unit buildings, usually two to four units.
A secondary suite is a legal second unit added inside or beside an existing house. A basement apartment and a garden suite are both secondary suites.

The line that matters most to a buyer is not the name. It is the unit count, because that is what drives the financing and the rules.

What Ontario Now Allows

Ontario has spent the last few years making it easier to add units. The More Homes Built Faster Act, known as Bill 23, passed in 2022. It lets property owners put up to three units on most residential lots across the province as of right. In most cases that means no minor variance and no rezoning. The province also removed development charges on those added units and dropped parking minimums for them.

Some cities went further. Toronto passed a multiplex bylaw in 2023 that permits up to four units as of right on residential lots across the whole city. Other municipalities have followed with their own versions.

For a buyer, this changes the math on a plain single-family house. A tired bungalow in the right spot is no longer just a house. It can become a legal duplex or triplex once the work is done. That is where the off-market, below-retail angle comes in.

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Where the Financing Line Falls

This is the single most useful thing to know. Residential mortgage financing in Canada covers buildings with one to four units. Once a building hits five units or more, it is treated as multi-residential or commercial.

That split matters:

A one to four unit building can be bought with a standard residential mortgage. Down payments and rates look like a normal purchase.
A five-plus unit building needs commercial financing. Lenders underwrite the property on its income, approval takes longer, and the deposit is usually larger.

Most newer investors do best starting in the one to four unit range. A fourplex is the ceiling of residential financing, and the entry point is low enough to buy without commercial lending. That is a big reason small multiplexes are in such demand.

The Secondary Suite Refinance Many Buyers Miss

There is a financing tool a lot of investors do not know about. Since January 2025, CMHC allows an insured refinance to help fund a new secondary suite. The headline terms are worth knowing.

You can borrow against up to 90 percent of the property value after the suite is built.
The property value can be up to two million dollars.
It applies to properties with up to four units in total.
The amortization can run up to 30 years.
The owner or a close relative must live in one of the units.

In plain terms, you can buy a house, add a legal unit, and pull much of that new value back out to fund the next deal. For a buyer who likes the BRRRR approach, this is a real lever. It works best when you buy the starting property below retail, which is exactly what off-market deals are for.

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Why Multi-Unit Fits Off-Market Buying

Multi-unit and suite-ready houses are a natural match for off-market deals. The sellers are often motivated for reasons that have nothing to do with price shopping.

Tired landlords who are done managing tenants and want a clean, firm sale.
Estates and probate sales where the family wants to close fast.
Owners of run-down duplexes and fourplexes that need work most retail buyers will not take on.
Houses on lots that allow extra units, where the current owner has no interest in building them.

These are the distressed and motivated situations that produce wholesale and below-retail pricing. You will rarely find them well advertised. That is the point of an off-market buyer list.

How We Source These Below Retail

Jania Group is a real estate investor and buyer. We are not an agent or a brokerage. We find off-market and wholesale properties directly, put them under contract, and pass them to our buyer list.

For multi-unit and suite-ready stock, that means we hunt for fixer uppers, distressed owners, and houses on unit-friendly lots across Ontario. When a deal lands, cash buyers and investors on our list hear about it first. Many of these come in well below what a cleaned-up, listed version would ask.

You can see the markets we cover on our Ontario off-market hub, and dig into specific markets like Toronto, Hamilton, and Windsor. For the full picture of how this works, start with our guide to buying off-market investment properties in Canada.

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Join the Ontario Buyer List

If you buy duplexes, multiplexes, or suite-ready houses, get on the list. You tell us your buy box once. We send deals that fit, before they reach the open market. There is no cost to join and no obligation on any single deal.