Usually none. They are the same building — a small self-contained home behind the main house — under whatever word the municipality happens to use. The exceptions are worth knowing, because where a bylaw does separate them it changes what you are allowed to build.
That is the answer for British Columbia. If your property is in Ontario the two words are not interchangeable at all — Toronto zones them separately — and the difference is set out below.
Rules read 2026-08-06 · Pre-screening only, not a permit determination.
Taken from each city's own bylaw and its summary of it, not from a thesaurus. Use the local word when you call the planning desk.
| Municipality | Its own term or terms |
|---|---|
| Burnaby | laneway homes |
| Coquitlam | garden cottages, carriage houses, laneway homes |
| Delta | coach houses, garden suites |
| Langley City | garden suites, carriage homes |
| Langley Township | coach houses, laneway homes |
| New Westminster | carriage houses, laneway houses |
| Richmond | coach houses |
| Surrey | coach houses, garden suites |
| Vancouver | laneway houses, laneway homes |
Where a city uses two words, both appear in its own documents and the page for that city leads with the one its residents search for.
The distinction that actually bites is the garage. Several bylaws define a coach house as a dwelling above or attached to a detached garage, which makes it a different building from a ground-oriented garden suite, and the access rules follow the garage rather than the home.
Surrey is the clearest case. Its coach house must be attached to a garage, and on the smaller-lot zones that garage's driveway has to come off a rear lane or a side street — so an interior lot with no lane cannot take one. A garden suite carries no such requirement and is the fallback in exactly that situation. Same back yard, same owner, two different answers depending on which word applies.
The other pattern is a bylaw that names only one form. Where that happens, that is the form permitted, and asking for the other one is asking for a different zone.
This is worth stating plainly, because the question gets asked far more often about Toronto than about Vancouver, and the answer there is the opposite of the answer here. Toronto treats the two as separate zoning categories decided by one fact: whether the property abuts a public lane.
The consequence is visible in the numbers: Toronto's pre-approved plans give a laneway suite a 1 m rear setback and 0 m side setbacks, and a garden suite 1.5 m at the rear and 1.5 to 3.0 m at the sides. Same city, same back yard, different envelope — because of the lane.
British Columbia has no equivalent province-wide split. Here the province groups both under detached accessory dwelling units, and it is each municipality that picks a word, which is why the table above has nine rows and five vocabularies in it. So a Toronto answer does not transfer to a BC lot, and a BC answer does not transfer to a Toronto one.
The words are municipal. What decides it is your zone, your lot and whether you have a lane. The free check reads all three from the city's own data.
In most of the Lower Mainland, yes — they are the same building under different municipal names, and the province groups them together as "detached accessory dwelling units (ADUs), like garden suites or laneway homes". The exceptions are real though: where a bylaw defines a coach house as a unit above or attached to a detached garage, it is a genuinely different building from a ground-oriented garden suite, and the rules that follow differ with it.
In the bylaws that use the term, a coach house is usually a dwelling above or attached to a detached garage, rather than a standalone building on the ground. That definition has consequences: in Surrey a coach house must be attached to a garage and needs lane or side-street access on the smaller-lot zones, while a garden suite needs neither and is the fallback where there is no lane.
No — and this is the one place the distinction is formal rather than linguistic. Toronto defines a garden suite as a detached self-contained home in the rear yard of a lot that is not on a public lane, and directs owners whose site does abut a lane to its separate Laneway Suites program, which carries different zoning and access rules. British Columbia has no equivalent province-wide split, so a Toronto answer does not transfer to a BC lot.
The table on this page lists each municipality's own vocabulary, taken from its bylaw and its summary of it. Using the local word matters more than it should: it is what the city's own documents, forms and staff will say back to you.
Sometimes. Where a bylaw names only one form, that is the form it permits — Richmond's coach-house zones and Langley Township's R-CL(CH) both tie the unit to a garage. Where a bylaw names both, they usually carry different setbacks or access requirements. Your city's page sets out which applies zone by zone.
The rules change at every city line. These pages are built from the same bylaw reads.
Terminology is taken from each municipality's bylaw as read on the dates shown on its own page. Only the municipality can tell you which form it will permit on a given lot.