By Farzad Esnaashari, M.Arch, OAA, Quadrant Architects
If you own a single detached house in an established Toronto neighbourhood, you have more options than you probably realize. One of the most useful is turning one house into three homes: a two-unit duplex with a separate garden suite in the backyard. On a single lot, that is three independent homes, what people call a 2+1.
We recently finished one on Kilbarry Road, in the Avenue Road area. Here is who the 2+1 suits, why you might choose it over other options, and what to check before you start.
A 2+1 is a two-unit duplex in the main house plus one garden suite (or laneway suite) at the back of the lot. Two homes in the house, one in the backyard, three in total. The duplex follows Toronto’s multiplex rules, and the backyard suite follows its own separate rules, which is why it does not count against the units in the main house. The two permissions stack on one lot.
How each piece works, the multiplex units and the garden suite rules, is covered in our separate guides. This one is about the bigger question: whether a 2+1 is the right move for your property, and why.
It tends to fit three situations well.
The multi-generational family. Parents in one duplex unit, adult children or aging parents in the other, and the garden suite as a private space for a caregiver, a grown child moving back, or grandparents who want their own place with family close by. Three homes, one property, everyone with their own front door.
The owner who wants to live well and earn income. Live in one unit, rent the other and the garden suite, and that income helps carry the property. In an expensive neighbourhood, it can be what makes staying in the area possible.
The long-term investor, who looks at an aging house on a good lot and sees that three rental homes on one well-located property is a more flexible asset than one tired house.
More units are not always the right answer. In our experience, a 2+1 has real advantages over packing in the maximum.
The homes are bigger and more livable. Two duplex units plus a proper garden suite gives you three generous spaces instead of four to six smaller ones squeezed into the same building. If you plan to live in one of them, that size and quality usually matters more than the unit count.
The garden suite also gives you something a fourplex cannot: a fully separate home, detached from the main house, with its own entrance and its own bit of yard. For family, or for a higher-end rental, that separation is worth a lot.
And a 2+1 stays in scale with an established street. In a neighbourhood of detached houses, a renovated duplex with a quiet garden suite behind it looks like a home, not a development. For a lot of owners around Avenue Road, Forest Hill, or Lawrence Park, fitting the street is part of the point.
It can, and that is a big part of the appeal. The worry owners raise in these areas is always the same: will adding units cheapen the property or clash with the street? Done well, it does not have to. The main house can be renovated to a high standard, the way we did on Kilbarry Road, where a blend of traditional and modern keeps the solid, well-built feel of an older home. The garden suite sits quietly at the back, off the street entirely. From the front, you see one well-kept house, and the three-home layout is not obvious.
A few things decide whether a 2+1 works on your lot:
Most of this can be settled in an early feasibility review, before you commit to a design or a purchase. That review is where we start on a project like this, as a multiplex architect working across Toronto’s established neighbourhoods, including the Avenue Road area, Forest Hill, Lawrence Park, Midtown, and North Toronto.
Farzad Esnaashari, M.Arch, OAA, Quadrant Architects. 416-835-0053 · farzad@quadrantarchitects.com
Current as of August 2026. Zoning and development charge rules change. Verify the rules for your specific address through the City of Toronto before making design or investment decisions.