A detached house stands on its own lot with no walls touching the home next door, while a semi-detached house shares one wall, called a party wall, with the house beside it. In Toronto both types are almost always freehold, so you own the structure and the land underneath it, but that single shared wall changes the price, the privacy, and the renovation rules that come with a semi-detached home.
The party wall is the defining feature of a semi. Two houses are built as mirror images and joined along one vertical wall, most often side by side. Each home sits on its own lot with its own deed, which is why a semi-detached property is bought and sold on its own and not as part of a corporation the way a condo is. A detached house has open air on all four sides and no attached neighbour.
In the older parts of the city core, the semi is everywhere. Neighbourhoods like Riverdale, Leslieville, the Annex, and Roncesvalles were laid out on narrow lots more than a century ago, and putting two homes on a shared wall made efficient use of that width. Detached houses in the same pockets are scarcer, which is part of why they carry a higher price.
Price is usually the biggest practical difference. Recent figures from the Toronto Regional Real Estate Board (TRREB) put the average detached home in the City of Toronto a few hundred thousand dollars above the average semi-detached, and that gap has held even as prices softened. For many buyers a semi is the way into a house with a backyard, a basement, and a freehold deed at a lower entry point than a detached home. That difference feeds directly into the income you need to buy a home in Toronto.
The trade-offs run the other way too. A shared wall means you can sometimes hear the household next door, and any work that touches the party wall usually needs a party wall agreement signed by both owners. A detached home gives you more sound separation and more room to renovate without coordinating next door.
Ownership works the same for both. Unlike a condo, a detached or semi-detached house normally comes with freehold ownership of the land, and the owner handles maintenance and property taxes directly. That also sets a semi apart from a freehold or condominium townhouse, which attaches to a whole row of units rather than a single neighbouring house.
Related reading: What Is the Difference Between a Freehold and Condo Townhouse in Ontario?, What Is the Difference Between Freehold and Leasehold in Ontario?, and Do You Need a Property Survey When Buying a Home in Ontario?
