A secondary suite is the most reliable way to add income to an island house, and it is also the renovation with the most ways to go wrong on paper. The good news is that the requirements are knowable, and most of them can be checked in an afternoon before you spend a dollar on design.
Work through this list in order. If you fail at step one or two, stop — the rest doesn't matter yet.
1. Zoning: is a suite permitted at all?
Most single-family zones in Victoria, Saanich, Langford, Colwood and Esquimalt now permit one secondary suite. But "permitted" comes with conditions that vary by municipality and sometimes by lot:
- Only one secondary suite per lot, and generally not alongside a garden suite
- Minimum lot area in some zones
- Maximum suite floor area — commonly 40% of the house's floor area or 90 m², whichever is less
- The property owner may be required to live on site in some municipalities
- Strata bylaws override everything if you are in a strata
Call your municipal planning counter with your address, or check the zoning map online. It is a fifteen-minute phone call and it answers the only question that can kill the project outright.
2. Ceiling height: the deal-breaker
The BC Building Code requires a minimum 1.98 m (6'6") clear ceiling height over the required floor area of a secondary suite, measured to the lowest projection — which means under ducts, beams and pipes, not to the underside of the joists.
Measure at the worst point in each room, not in the middle. If you are at 6'8" you have room to work. At 6'4", the first move is re-routing ductwork and relocating a beam pocket, which is usually cheaper than anyone expects. Below 6'2", you are looking at lowering the slab:
| Method | Height gained | Typical cost |
|---|---|---|
| Re-routing ducts and plumbing | 50–200 mm | $3,000 – $9,000 |
| Bench footing (interior ledge) | 300–600 mm | $28,000 – $55,000 |
| Full underpinning | 600 mm+ | $55,000 – $95,000 |
3. Egress: a way out of every bedroom
Every sleeping room needs an openable window providing an unobstructed clear opening of at least 0.35 m², with no dimension less than 380 mm, openable from the inside without tools or special knowledge. If the window is below grade, the well in front of it must give at least 550 mm of clear projection and must drain.
Cutting a new egress opening through a concrete foundation wall means saw-cutting, a lintel, waterproofing the new opening and building a drained well: budget $6,500 to $11,000 per window installed. It is one of the most common line items on a suite quote and it is not optional.
4. Fire separation between the units
The suite and the principal dwelling must be separated by a fire separation with a one-hour fire-resistance rating — floor/ceiling assembly and any shared walls, with penetrations firestopped and the door between units rated and self-closing where one exists.
In practice this means 5/8" Type X gypsum board on the ceiling of the suite, insulation in the joist space, sealed penetrations at every pipe, duct and wire, and firestopping at the top of shared walls. It has to be inspected before you cover it, which is why fire separation is its own inspection stage.
Sound is not the same as fire
A one-hour fire separation is not automatically a good sound separation. The code target is STC 50, and the difference between a suite that rents easily and one that doesn't is often footfall noise. Resilient channel on the ceiling, sound-attenuating batts in the joist space and, ideally, an acoustic underlay upstairs will get you there. It costs perhaps $3,500 more on a typical suite and it is the upgrade tenants notice most.
5. A separate entrance
The suite needs its own exterior entrance that does not pass through the principal dwelling. On an island lot this is usually an exterior stair to a below-grade door, or a door on a walk-out elevation. The path to it must be lit and, in most municipalities, hard-surfaced and at least a metre wide.
6. Smoke and CO alarms, interconnected
Hard-wired, interconnected smoke alarms in both dwelling units — so a fire in the suite wakes the family upstairs — plus carbon monoxide alarms where there is any fuel-burning appliance or an attached garage. This is a small line item and it is the one an inspector will absolutely check.
7. Independent heating and ventilation
The suite needs its own controllable heat source and continuous mechanical ventilation. The default answer on the island is a ductless heat pump: independent control, quiet, efficient, and it dehumidifies through our damp shoulder seasons. Sharing the main house furnace across the fire separation creates a duct penetration problem and a billing problem, and we advise against it.
8. Parking
Most island municipalities require one additional off-street parking space for a secondary suite, though several have relaxed this near frequent-transit corridors. Check before you design, because a required space can eat the garden you were planning to keep and occasionally decides where the entrance goes.
9. Electrical capacity and metering
A 100 amp service will not comfortably carry a main house plus a suite with electric heat, a range and a hot water tank. Plan on a 200 amp upgrade ($4,500–$9,000 including BC Hydro coordination). Separate metering is optional and rarely worth the $3,000 to $5,000 unless the suite's consumption is likely to be unusual; most owners fold utilities into the rent.
10. What it costs, what it returns
| Line item | Typical range |
|---|---|
| Design, drawings, permit fees | $8,000 – $14,000 |
| Egress windows (2) | $13,000 – $20,000 |
| Framing, insulation, drywall | $26,000 – $38,000 |
| Fire separation and sound package | $9,000 – $15,000 |
| Electrical incl. service upgrade | $18,000 – $28,000 |
| Plumbing, kitchen and bathroom | $28,000 – $42,000 |
| Heat pump and ventilation | $7,500 – $12,000 |
| Flooring, doors, trim, paint | $14,000 – $22,000 |
| Total, one-bedroom suite | $123,500 – $191,000 |
Against that, a one-bedroom suite in Greater Victoria was renting in the $1,500–$1,900 range through the first half of 2026. Run your own numbers with your own vacancy and maintenance assumptions, and talk to an accountant about the tax treatment of rental income and the capital-gains implications of using part of your principal residence to earn income. Those consequences are real and they are outside our lane.
11. What being a landlord actually involves
The build is the easy part. Before you commit, read the Residential Tenancy Act, understand that you cannot end a tenancy simply because you'd like your basement back, and be honest about whether you want someone living below your floor. Plenty of island homeowners are delighted; a few discover after a year that they would rather have the storage.
The half-day feasibility check
Before design: call planning about zoning, measure your lowest ceiling point in four rooms, look at where an egress window could go on each elevation, and open your electrical panel and photograph the label. Those four answers tell an experienced builder about 80% of what a suite will cost you.
Talk it through with someone who builds these
We give straight answers on the phone whether or not you hire us. If this guide raised a question about your own house, get in touch — or read about our basements & legal suites service.
Written by Priya Raghunathan, Permits & compliance lead at Island Home Renovations.
