Edmonton allows four kinds of secondary suite on most residential lots: a basement suite inside the main house, a garage suite above a detached garage, a garden suite as its own small building, and, if you already have a duplex, a second unit inside it. For a homeowner looking at rental income, mortgage helper, aging-parent housing, or an adult child moving back, this is the single largest zoning shift of the last decade in this city.
We build all four. Here is what each one means in practice, roughly what each costs, what makes each legal, and the incentive programs most owners do not know about until we mention them in the first site walk.
What "legal" actually means
A legal secondary suite in Edmonton has, at minimum, four things. Its own separate entrance from the outside. A full second kitchen. A bathroom. And a code-compliant fire separation from the main dwelling, which usually means a one-hour rated ceiling assembly and mineral-wool insulation in the shared wall or ceiling. It also has to satisfy egress out of every bedroom, meaning a window big enough and low enough to climb out of, or a walk-out door.
That is the short list. The full list includes ceiling height minimums (usually 1.95 metres over most of the floor area for a basement suite), a separate heating source or a shared system that meets specific code language, a sound-transmission rating between units, and hardwired interconnected smoke and carbon monoxide detectors on both sides.
A suite without any one of those is not legal. It might rent. It will not close cleanly on resale, insure honestly, or qualify for the grant program below.
Basement suites
The most common conversion, and the one most Edmonton homes can support. If you own a 1960s bungalow with a walk-out or a full-height basement, adding a legal basement suite is often a $60,000 to $110,000 project depending on how much demo is needed, whether egress windows have to be cut into the foundation wall, and how far the plumbing has to be re-run.
Two flavours matter. A conversion of an existing partly-finished basement is one project. A retrofit of a house whose basement was never intended for occupancy is another one entirely. On the latter you are often digging window wells, cutting new concrete, and moving the furnace and hot water tank to make room for a proper suite kitchen and a second bathroom. That is where the number climbs.
The rent number in the mature core in 2026 is $1,300 to $1,900 per month for a decent one-bedroom basement suite, higher for a two-bedroom or a fully separate entry with a proper backyard access.
Garage suites
A garage suite sits above a detached garage. The garage stays as parking, and the second storey becomes a self-contained one-bedroom or two-bedroom unit. On a typical Edmonton lot with a rear-loading garage, this is a $220,000 to $380,000 project all-in, depending on size, finish level, and how much you spend on the exterior to make it belong to the main house.
The catch is site coverage. The city regulates how much of your lot can be covered by structures, and a garage suite counts against that budget. On a narrow lot with an ambitious main house, you may not have the coverage left to add a garage suite legally, no matter how much you want one. This is the single most common reason we tell an owner they need to pick between a bigger house and a garage suite. It is worth a zoning check before you fall in love with the idea.
Garden suites
A garden suite is a small standalone building on the same lot as your main house, usually in the backyard. Edmonton legalized these city-wide in 2018 and they have quietly become the most flexible option, especially for owners who do not want to share plumbing walls with a tenant.
Cost: $180,000 to $320,000 for a decent one-bedroom garden suite of 500 to 700 square feet, more for a fully finished 900 square foot two-bedroom. That is total install including foundation, utility service, mechanical, and finish. It does not include your landscaping or the deck between the buildings.
The rules that trip owners up: garden suites cannot exceed one storey plus a loft in most residential zones, they have to sit within specific setback distances from all lot lines, and they cannot exceed a fixed floor area (typically 75 square metres). None of these are showstoppers, but they narrow the design space in a way that a $300,000 project deserves to be understood before it starts.
Rowhouse and duplex second units
If you already own a semi-detached or a duplex, you can often add a legal secondary suite in the basement of one or both sides. Same rules as a single-family basement suite, applied to each dwelling unit. The mechanical and separate entry problems are usually easier to solve because the shell was already designed for two households.
The permit path
All four suite types require a Development Permit and a Building Permit from the City of Edmonton. In practice this means:
- Development Permit first, sized to your specific lot and design. This is where the site-coverage, setback, and parking rules get checked. Approval usually takes 4 to 8 weeks and includes a 21-day appeal period any neighbour can file into.
- Building Permit second, which reviews the actual construction plans for code compliance. This is faster, usually 3 to 6 weeks for a suite scope, less if we have submitted a similar package recently and the reviewer is familiar with our detailing.
For the deeper permit timeline, see our Edmonton infill permit timeline post. The permits pillar covers Mature Neighbourhood Overlay rules that can affect suite additions in older neighbourhoods.
The grant program
The City of Edmonton runs a Secondary Suite Incentive Program that pays out real money to eligible homeowners who create a new legal suite. The number moves year to year and is subject to funding, but recent grants have been in the $15,000 to $25,000 range for a suite that meets all program criteria.
Most owners don't know about it going in, and it doesn't apply retroactively to already-completed suites. This is one of those cases where the paperwork order matters: apply before you start, follow the program's specific inspection sequence, and file the closeout paperwork. We cover the specifics in Edmonton's Secondary Suite Incentive Program.
Rent-out reality check
The rent numbers above are current, but the market is not the only thing that determines whether a suite pencils. Insurance for a house with a legal secondary suite runs 15 to 30 percent higher than the same house without one. Utilities may be shared or separated depending on how you built it. Property tax classification does not usually change (it is still your principal residence), but if you rent both units and move out, it does.
Our rough rule for the mature core: a $90,000 basement suite conversion adds roughly $1,600 in gross monthly rent and $6,000 to $9,000 in annual net income after utilities and vacancy. Payback period 10 to 15 years, and the suite improves resale by roughly the same $90,000 or more. A garden suite at $280,000 adds $1,800 to $2,400 in gross rent and pays back over a longer horizon, but adds a full building to the property that stands on its own on resale.
Which one is right
- Own a bungalow with a decent basement and want the fastest return: basement suite.
- Have a rear-loading garage and want to keep parking: garage suite.
- Have a big backyard and want a separate building for a parent or an adult child: garden suite.
- Have a duplex: convert both basements to suites simultaneously, one design permit, one construction mobilization.
Direct cost comparisons for all three are in garage vs garden vs basement suite cost Edmonton. And if you have a specific lot in mind, we do the site walk free. The parking, setback, and coverage rules answer themselves once the tape measure is out.