What is a garden suite?
A garden suite (also called a backyard suite, coach house or detached ARU) is a separate dwelling on the same lot as your house. It has its own kitchen, bathroom, sleeping area and entrance. In Kingston it is permitted as a detached additional residential unit, subject to zoning and servicing rules.
Because it stands apart from the main house, a garden suite gives the most privacy of any ARU type. That makes it the usual choice for aging parents, adult children and long-term tenants who want a home of their own.
Kingston garden suite rules to know
These are the rules that most often decide whether a garden suite works on a lot. They come from the City of Kingston ARU guidance.
| Rule | What it means for you |
|---|---|
| Zoning compliance | The lot must meet the ARU provisions in the zoning bylaw, including setbacks and lot coverage. |
| Size | The ARU's gross floor area can be equal to or less than the main house. |
| Parking | At least one space, which can be tandem. |
| Excluded areas | Sewer surcharging and capacity limit areas, Loughborough Lake, and natural hazard lands. |
| Water service | Older half-inch water services may need an upgrade. A City grant can cover part of it. |
| Existing units on the lot | Not permitted where the lot already has two or more units or a garden suite. |
What a garden suite project includes
- Site and servicing review: water, sewer and hydro routes, access for equipment, and grading.
- Design: a layout sized to your lot and goal, from a studio to a two bedroom unit.
- Permit drawings and application: prepared to the Ontario Building Code and submitted to the City.
- Foundation, framing and envelope: built for Kingston winters, with insulation and air sealing that keep heating bills low.
- Services and finishes: plumbing, electrical, heating and cooling, kitchen and bath.
- Inspections and occupancy: we book each City inspection and close the permit.
Garden suite vs basement apartment
| Garden suite | Basement apartment | |
|---|---|---|
| Privacy | Highest, separate building | Shared walls and floor |
| Natural light | Windows on all sides | Limited by grade |
| Construction scope | New foundation and structure | Works inside the existing house |
| Kingston incentive cap | Up to $40,000 | Up to $30,000 |
| Yard space | Uses part of the yard | Yard unchanged |
Not sure which fits? Compare with our basement apartment service or see every option on the secondary unit services page.
Can the City help pay for a garden suite?
Kingston's Detached ARU Incentive offers a forgivable loan of up to 50% of project cost or $40,000, whichever is less. It is forgiven over five years if you rent at or below 90% of average market rent to an income-eligible tenant. New applications are currently waitlisted.
Read the full conditions in our Kingston ARU incentive program guide, and compare other options in the secondary suite financing guide.
Frequently asked questions
Can I build a garden suite on my Kingston lot?
Many Kingston lots qualify, but not all. The lot must meet the zoning bylaw ARU provisions, and some areas are excluded, such as places with sewer capacity limits, Loughborough Lake and natural hazard lands. We check your address against these rules before any design work.
How big can a garden suite be in Kingston?
The City says the additional unit can be equal to or smaller in gross floor area than the main house. Height, setbacks and lot coverage also limit the size, and those vary by zone. We confirm the real maximum for your lot during the property check.
Does a garden suite need its own parking space?
Kingston requires at least one parking space for an ARU, and it can be in a tandem arrangement, meaning one car parked behind another in the same driveway. Your lot may have other parking rules, so we review it during design.
Can a garden suite be rented out?
Yes. A permitted garden suite is a legal dwelling and can be rented long term. If you take the City forgivable loan, rent is capped at 90% of average market rent for five years and the tenant must meet an income limit.