Garden suites, laneway houses and ADUs
Multi-generational living was once the norm rather than the exception. Accessory dwelling units are bringing it back, and the rules have moved a long way in the last few years.
A self-contained dwelling on an existing property
Usually with its own bedroom, private bathroom, kitchen and living room. It preserves the privacy and autonomy of everyone involved while keeping them close, which is the whole point of it and the reason the arrangement is returning.
Demand is strong along the west coast, in Washington, Oregon, California and Hawaii, and locally in Victoria and across Vancouver Island.
What your municipality calls it
The terminology shifts by region and it matters, because the words in your local bylaw are the ones that decide what you can build.
You will also see auxiliary dwelling unit, which is a common slip for accessory. For the version with a garage underneath, see carriage house plans.
The rules have changed, and they decide everything.
Zoning is the thing to establish before design, before budget, before anything. It determines what is buildable on your lot, and no plan can work around it.
British Columbia has legislated province wide on small scale multi-unit housing, which has moved the position considerably from where it stood only a few years ago. Municipalities across Canada and the United States have been changing their own rules alongside it.
What varies most between jurisdictions:
- Whether rezoning is required, or approval is handled by staff
- Rules on rental use, and whether short term letting is permitted
- Entrance placement, parking requirements and setbacks
- Maximum size, often set relative to the main house or the lot
- Building height and its relationship to neighbouring properties
Ask your municipality what applies to your specific lot. It takes one call and it is the only answer that stays correct.
Five reasons, and most owners have two of them
Rental income
A garden suite is a straightforward source of supplemental income, whether that goes against the mortgage or into savings. Some owners go further and move into the suite themselves, renting out the principal residence, which usually produces considerably more.
Short term letting is an alternative where the municipality permits it, and it leaves you in control of when the space is occupied. Check that first, because rules on short term rental have tightened in a lot of places.
Aging parents
Independence with help close by. The cost of retirement accommodation puts it out of reach for a lot of families, and a garden suite lets someone keep their own front door while family are a few steps away in the main house.
Worth designing for the whole span rather than today. Accessible design covers the dimensions that matter and the blocking to build in now.
Adult children
An unpredictable job market and high housing costs make it hard for graduates and young couples to establish themselves. A garden suite can be the transition: independence while saving toward a place of their own, whether you charge nominal rent or nothing at all.
More space, more cheaply than an extension
It is frequently cheaper to build a separate small building than to add on to an existing house. An extension means opening up a house people are living in, matching existing structure and finishes, and disrupting the household throughout. A separate building avoids all three.
Somewhere to actually work
A separate building solves the home office problem in a way a spare bedroom does not. The physical separation from the household is the point: fewer interruptions, a clearer boundary at the end of the day, and no negotiating over the kitchen table.
Most people building one have two of these in mind at once, and that is worth saying at the design stage. A suite planned as an office that might later house a parent is a different building from one planned as either alone.
Garden suite questions
A self-contained dwelling on an existing property, usually with its own bedroom, bathroom, kitchen and living area. It preserves the privacy and independence of everyone involved while keeping them close. The same building is called a laneway house where it fronts a rear lane, a secondary suite, a coach house, or an accessory dwelling unit across most of the United States.
Mostly geography. Accessory dwelling unit is the standard term across the United States, garden suite is common in Ontario and British Columbia, laneway house is used where the unit fronts a rear lane, and coach house or carriage house usually implies living space above a garage. The building is broadly the same; what differs is what your municipality calls it and what it permits.
Check with your municipality before anything else, because the rules have changed substantially in recent years and they decide what is buildable before any plan does. What varies most is whether rezoning is required, rules on rental use, entrance placement, parking, building height and setbacks. British Columbia has legislated province wide on small scale multi-unit housing, which has moved the position considerably from where it stood a few years ago.
It adds living space and a potential income stream, and it is frequently cheaper to build a separate small building than to extend the existing house. Whether that translates into resale value depends on your local market and on what the municipality permits a buyer to do with it.
Most fall between roughly 500 and 1,200 square feet, which is enough for a bedroom, bathroom, kitchen and living area with the proportions still feeling generous. Municipal rules often cap the size relative to the main house or the lot, so the ceiling is usually set by zoning rather than by preference.
Related pages
Tell us what your municipality allows.
Once you know the size, height and setback rules for your lot, we can tell you what fits. Design, estimating and engineering are included in the package rather than billed separately.