What Is a Basement Apartment Called? Canada’s Regional Words

Canada has an unusual problem for a country of forty million people: it has no shared vocabulary for its most common form of rental housing. The identical below-grade unit is called four different things depending on which side of a provincial border it sits, and detached versions add four more.

That’s not a curiosity. It’s the single most common reason a homeowner concludes their city “doesn’t allow” something. They searched the wrong word.

This is the translation table.

What is a basement apartment called across Canada?

The split runs roughly along the Ontario–Manitoba line. East of it, “apartment.” West of it, “suite.” Nobody planned this; it’s just how the usage settled.

“Secondary suite” is the one that crosses all boundaries. It’s the term in municipal zoning bylaws from Surrey to Toronto, and it’s what CMHC uses in its lending documents. If you only remember one word from this page, make it that one.

What do the detached versions get called?

When the unit is a separate building in the rear yard rather than part of the house, the vocabulary fragments further — and here the words carry genuinely different rules.

Toronto is the case where this genuinely matters most. A laneway suite and a garden suite are not two names for one thing — they are two separate regulatory categories with different rules. The City defines a garden suite as accommodation in an ancillary building ”usually located in the rear yard, but not on a public lane,“ while a laneway suite is ”typically located in the back yard next to a public laneway.”

If your Toronto lot has no lane behind it, you are not disqualified from backyard housing — you’re in the garden suite rulebook instead. A great many homeowners conclude the opposite and stop looking.

Edmonton changed its terminology recently. Zoning Bylaw 20001 now regulates rear-yard units under “Backyard Housing” — a single category replacing what the City previously called garage suites and garden suites. Search results still return the older words, so if you’re reading Edmonton guidance, check which era it’s from.

Which term should I actually search?

Two searches, in this order:

1. Your municipality’s name + “secondary suite.” This almost always reaches the right page, because it’s the bylaw term nationally.

2. Your municipality’s name + your local word from the tables above, if the first search comes up thin.

What not to search: “ADU.” Accessory dwelling unit is an American planning term and appears in almost no Canadian bylaw. You’ll get US rules, which differ substantially. Same problem with “granny flat,” which is Australian and British.

A useful shortcut: go to your municipality’s own website and use its internal search rather than a general search engine. Municipal pages carry a “date modified” stamp, which is the single most useful thing on them — a lot of the third-party content about Canadian suite rules is two years stale.

Why does the word matter so much?

Because the word determines which rulebook you land in, and the rulebooks genuinely differ.

Different provinces, different codes. Minimum ceiling height for a suite is 1.95 m in Alberta, 2 m in British Columbia, and 1.95 m in Ontario basements. Egress sill heights differ. Fire separation requirements differ — Ontario gives houses more than five years old a concession that Alberta doesn’t frame the same way. Guidance written for one province is unreliable in another, and the vocabulary is what tells you which province you’re reading about.

Different categories, different rules. Within Toronto, laneway and garden suites have different size limits and different eligibility. Searching “laneway suite” when you don’t have a lane returns rules you can’t use.

Different eras, different terms. Edmonton’s “garage suite” content predates its current bylaw. Vancouver’s laneway house rules changed in 2023. The word can date the page.

The practical consequence is wasted weeks and, occasionally, a design based on the wrong constraints. Our zoning and bylaws guide covers what a municipality actually assesses once you find the right page.

Are these real planning terms or just slang?

Both, and it’s worth knowing which is which.

Real planning terms — they appear in bylaws:

• Secondary suite. Governed in Toronto by Section 150.10 of Zoning By-law 569-2013. Used in Calgary’s, Surrey’s and Edmonton’s bylaws.
• Garden suite and laneway suite. Both defined in Toronto’s zoning bylaw, with separate provisions.
• Laneway house. Regulated under its own section of Vancouver’s Zoning and Development By-law.
• Coach house. The live planning term in Surrey and Ottawa.
• Backyard Housing. Edmonton’s current category under Section 6.10 of Zoning Bylaw 20001.

Descriptive rather than regulatory:

• Basement apartment and basement suite. Universally understood, and used on municipal pages, but the bylaw usually says “secondary suite.”
• In-law suite. No planning meaning — though it has real tax meaning, since a unit for a qualifying relative may attract the federal Multigenerational Home Renovation Tax Credit.
• Granny flat, carriage house. Descriptive only.

So the terms aren’t slang. Most of them are live planning language in at least one Canadian municipality — just not in all of them at once.

Find out which rules apply to your property

Knowing the word gets you to the right page. What that page permits on your lot depends on your zoning, lot dimensions and servicing.

HouseLyft’s free property assessment works those out for your specific address across the markets we cover. Our service areas page lists them, and our secondary suites overview is the hub for the whole category. Request your free report.