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A garage, though, is built as an unheated space next to the house, not as living space. Its slab is usually uninsulated and sloped toward the door, often sitting lower than the house floor, its walls and ceiling may have little or no insulation, and the wall it shares with the house is built to keep car exhaust out. Converting it means rethinking all of that, plus the zoning question of where the car goes once the garage is gone.
This page covers what a garage can become, the fire separation and carbon monoxide rules when part of it stays a garage, the slab and floor, zoning and parking, permits, the steps of the work and what a conversion means when you sell. For building a new garage, see our garage builders page.
Converting an attached garage to living space: full, partial or a separate unit
- A full conversion turns the whole garage into rooms connected to the house, with the overhead door replaced by an insulated wall and windows.
- A partial conversion keeps one bay for a car or storage and turns the rest into a room, which leaves a garage wall inside the house that must still meet the garage separation rules.
- A home office, gym or family room is the simplest use, since it needs no plumbing and no bedroom exit window.
- A bedroom brings code requirements for an egress window and alarms, and can't have a door opening straight into a remaining garage.
- A separate rental unit is a second dwelling in law, with its own zoning approval, fire separation and exit rules; our basement renovations page explains the equivalent rules for suites.
Fire separation and carbon monoxide when part of the garage stays a garage
Whenever living space and a garage share a wall or ceiling, the building code treats that boundary as a barrier against fumes. In the National Building Code, as reproduced in British Columbia's code, Article 9.10.9.16 requires an air barrier system between an attached garage and the rest of the building that is an effective barrier to gas and exhaust fumes. Article 9.10.13.15 requires any door between them to be tight-fitting, weather-stripped and self-closing, and doesn't allow that doorway in a room intended for sleeping. A partial conversion therefore has to build a new, fully sealed separation, and a new bedroom can't open onto the remaining bay.
Health Canada's carbon monoxide advice applies directly: don't idle vehicles in the garage even with the overhead door open, keep the door between the house and garage closed, and have at least one carbon monoxide alarm with battery backup, with hallways outside sleeping areas the most important place for it. Your province's code and the municipal inspector confirm what applies to your project.
Insulating the garage slab and raising the floor to meet the house
The garage floor is usually the biggest design decision. A slab poured for cars is sloped for drainage, rarely insulated and often a step or more below the house floor, so most conversions either build a new insulated floor on top of the slab, leveling it and bringing it up toward the house floor, or accept a step down and insulate over the slab with a thinner assembly. Either way, Natural Resources Canada's advice for insulating over concrete applies: put a moisture barrier on the floor or seal it, so moisture can't accumulate between the insulation and the slab.
- Check the headroom after raising the floor, since garage ceilings are not always as high as they look.
- Walls and the ceiling usually need insulation and a continuous air and vapour barrier added, since many garages were left unfinished inside.
- The overhead door opening is framed in with an insulated wall, windows or a door, and cladding outside that matches the house.
- Any floor drain in the slab has to be dealt with by a plumber, since a dry trap in a heated room can let sewer gas in.
Zoning, parking requirements and building permits for a garage conversion
Zoning is often the first obstacle. Ontario's citizen's guide to land use planning notes that zoning bylaws control parking requirements along with setbacks, heights and densities, so a bylaw may require your lot to keep one or more parking spaces, and turning the garage into a room can leave you short. In Ontario, a design that doesn't meet the bylaw may be eligible for a minor variance from the committee of adjustment; elsewhere, ask your municipality's planning department what applies.
A building permit is normally required. Toronto's permit guidance, for example, requires one for structural or material alterations, for new windows or doors where there were none before, and for enlarging or relocating existing ones, all of which a typical conversion includes. A separate unit adds its own requirements: Ontario's guidance on second units says a building permit is needed and a unit can't be added if you can't comply with your municipality's bylaws.
How a garage conversion is done, from permit to finishes
- Confirm zoning and parking with the municipality, then have drawings prepared showing the floor, the new wall and windows, and any fire separation.
- Clear the space, plan what happens to equipment the house relies on, such as a water heater, panel or laundry hookups, and have any gas appliance in the garage assessed by a licensed gas technician.
- Frame in the door opening and install windows and any new exterior door, with flashing tied into the existing wall.
- Build the new floor, then have electrical and any plumbing roughed in by licensed trades and inspected.
- Insulate the walls, ceiling and floor with a continuous air and vapour barrier, and extend heating by adding a ductless heat pump or a ducted zone sized for the room.
- Drywall, flooring and trim, then the final inspection, with smoke and carbon monoxide alarms in place.
Garage conversions and resale: parking, permits and keeping it reversible
A converted garage adds living space, but in a snowy climate many buyers value a garage too, so how a conversion affects resale depends on the neighbourhood, the lot and whether street or driveway parking remains. A permitted, well-built conversion with a floor level with the house and windows that suit the elevation reads as part of the home; a room with a step down, an obvious filled-in door opening and no permit on file raises questions from buyers, appraisers and insurers.
- Keep the permit, the inspection records and the drawings, since buyers and their lawyers may ask for them.
- Keeping the driveway usable for parking softens the loss of the garage for most buyers.
- A design that could be turned back into a garage later, such as a framed-in opening with a removable wall, keeps options open.
- Talk to your insurer before the work, since the change affects how the building is described in your policy.
Garage Conversions: frequently asked questions
Do I need a permit to convert my garage into a room?
Almost certainly. A conversion usually adds windows or doors, changes the floor and walls, and turns unheated space into living space, all of which municipalities review. Check zoning and parking requirements first, since they can block the project before any permit is considered.
Can I turn my garage into a bedroom?
Often, yes, if the room gets an egress window, smoke and carbon monoxide alarms, insulation and heat. If part of the garage stays a garage, the building code doesn't allow the door between the garage and the house to open into a room intended for sleeping.
How do you heat a converted garage?
Usually with a ductless heat pump or by extending the home's ducts if the furnace has capacity, after the walls, ceiling and floor are properly insulated. Unvented fuel-burning heaters don't belong in living space. Have an HVAC contractor size the system for the room.
Does converting a garage hurt resale value?
It depends on the market and the lot. Extra living space can appeal to buyers, but losing covered parking can put some off. A permitted conversion that looks like part of the house, with parking still on the driveway, is far easier to sell than one done without a permit.
Can I make my garage into a rental unit?
Only if your municipality's zoning allows an additional unit on your lot and the unit meets the building and fire code requirements for a separate dwelling. Start with the planning department, then have the unit designed and permitted as a dwelling, not as a spare room.
Sources
- British Columbia Building Code 2018, Division B, Section 9.10: Fire Protection (Articles 9.10.9.16 and 9.10.13.15) — Province of British Columbia
- Health Canada: Preventing carbon monoxide exposure
- Natural Resources Canada: Keeping the Heat In, Section 6: Basement insulation
- Government of Ontario: Citizen's guide to land use planning, Zoning bylaws
- City of Toronto: When do I need a building permit?
- Government of Ontario: Add a second unit in your house
Written by the LokalMatch editorial team. Reviewed by Zubair Afzal on September 10, 2026. How we write and check our guides