A garage is a small house without plumbing: foundation, framing, roof, electrical and a very large door. In Ontario in 2026, a detached double garage typically costs $40,000–$80,000 built by a contractor, while an attached double garage runs $60,000–$120,000 because it must meet fire-separation and tie-in requirements.
Prefab and kit garages cut 15–30% off those figures if you can manage the project yourself. Figures below are NorthPeak planning estimates including foundation, framing, roofing, siding, electrical and doors.
Cost by garage type
| Type | Typical size | Budget range |
|---|---|---|
| Detached single | 12x20 ft | $25,000–$50,000 |
| Detached double | 24x24 ft | $40,000–$80,000 |
| Attached single | 14x22 ft | $35,000–$70,000 |
| Attached double | 24x24 ft | $60,000–$120,000 |
| Detached double with loft/apartment | 24x28 ft | $90,000–$160,000+ |
Where the money goes
- Foundation ($8,000–$20,000): monolithic slab is cheapest; full frost-wall foundation costs more but allows a loft or future apartment.
- Framing and roof ($12,000–$30,000): trusses vs. stick-framing; a loft-ready roof costs more upfront.
- Garage doors ($1,500–$5,000 each): insulated 16x7 ft doors with openers; carriage-style and glass cost more.
- Electrical ($2,000–$5,000): subpanel, lighting, outlets — and a 240V circuit now if an EV charger is in your future.
- Siding and finishing ($5,000–$15,000): matching the house siding costs more than basic vinyl but protects resale.
Permits and setback rules
Detached garages need building permits in Ontario, and zoning by-laws dictate setbacks from lot lines (commonly 1–1.2 m from side/rear lines), maximum accessory-building size and lot coverage. Attached garages additionally require fire separation (drywall and sealed penetrations) between garage and house. Check zoning first — a garage that violates setbacks is a non-starter no contractor can fix.
Future-proofing tip: run a 240V/60A circuit and insulate the garage during construction even if you do not need them today. Retrofitting either later costs triple.
Frequently asked questions
How much does it cost to build a garage in Ontario in 2026?
Detached double: $40,000–$80,000. Attached double: $60,000–$120,000. Single-car detached: $25,000–$50,000. Kit/prefab options save 15–30%.
Is it cheaper to build a detached or attached garage?
Detached is cheaper to build — attached garages require fire separation, tie-in to the house structure and matching finishes, adding roughly 30–50%.
Do I need a permit for a garage in Ontario?
Yes, building permits are required. Zoning sets side/rear setbacks, max accessory building size and lot coverage — verify before designing.
Does a garage add value to a home in Ontario?
Yes, particularly in winter cities — appraisers and buyers consistently value garage parking. A well-built double garage typically recovers 60–80% of its cost at resale.
Sources and methodology
- Vista Builders: Home Renovation Cost in Ontario (2026 Guide)
- Canada Mortgage and Housing Corporation (CMHC)
- HomeStars
This article provides general information for planning purposes, not professional advice or a quote. Cost figures are NorthPeak planning estimates unless a source is named; confirm current prices with licensed local contractors and professionals before making decisions.