How Much Does a Home Addition Cost in Ontario?
Need more space but don't want to move? A home addition in Ontario typically costs $150 to $400+ per square foot, depending on the type of addition and complexity. Here's what homeowners in Brantford, Kitchener, Hamilton, Cambridge, Guelph, Brampton, and Mississauga can expect.
Cost by Addition Type
- Single Room Addition (200-400 sqft): $40,000–$120,000
- Second Storey Addition: $150,000–$350,000+
- Sunroom / 3-Season Room: $20,000–$60,000
- Garage Conversion: $25,000–$60,000
- In-Law Suite Addition: $80,000–$200,000
- Bump-Out (50-100 sqft): $15,000–$40,000
What Affects the Price?
The biggest cost factors are: foundation work (slab vs crawlspace vs full basement), whether you need structural engineering, roofline changes, plumbing and electrical additions, and your choice of finishes. Second storey additions cost more because they require structural reinforcement of existing walls and foundation.
Permits for Home Additions
Every home addition in Ontario requires a building permit. You'll also need engineering drawings and possibly a site plan. In Brantford and the Region of Waterloo, the permit process takes 2-6 weeks. Build My Home Ltd handles everything — drawings, permit applications, and all inspections.
Addition vs Moving
When you factor in realtor fees (5%), land transfer tax (1-2%), moving costs, and the price difference between your current home and a larger one, an addition is often more cost-effective — especially in today's Ontario housing market. Plus, you stay in your neighborhood and keep your current mortgage rate.
Get a Free Addition Quote
Build My Home Ltd builds room additions, second stories, sunrooms, and in-law suites across Brantford, Kitchener, Waterloo, Cambridge, Hamilton, and Guelph. Call 204-205-2064 for a free consultation.