The cost to underpin a basement in Toronto is$350 to $800 per linear foot of foundation wall for the underpinning itself, and $75,000 to $150,000 for a complete basement lowering once everything else is included.
Underpinning a basement in Toronto costs $350 to $800 per linear foot of foundation wall. A full basement lowering on a Toronto semi runs$75,000 to $150,000 including geotechnical work, structural engineering, permits, excavation, soil disposal, the new slab and plumbing. A 600 square foot basement lowered two feet lands at approximately$62,900 all in.
The line items
| Work | Toronto 2026 range |
|---|---|
| Geotechnical investigation | $2,500 to $5,000 |
| Structural engineering and stamped drawings | $3,500 to $8,000 |
| Permits and permit management | $1,500 to $4,000 |
| Underpinning, per linear foot | $350 to $800 per linear foot |
| New concrete slab | $6,000 to $12,000 |
| Helical piles, where soil requires them, per pile | $1,200 to $2,000 per pile |
Note how much of this is not concrete work. Engineering, geotechnical investigation and permits alone come to roughly $7,500 to $17,000 before anyone picks up a shovel, and those costs are largely fixed regardless of basement size.
Which means a small underpinning job is disproportionately expensive per square foot. Halving the basement does not halve the price.
A worked example
A Toronto semi with a 600 square foot basement, 20 feet by 30 feet, 100 linear feet of foundation wall, lowered two feet.
| Work | Toronto 2026 range |
|---|---|
| Underpinning, 100 lin ft at mid-range | about $40,000 |
| Engineering, geotechnical and permits | about $9,000 |
| Excavation, soil removal and disposal | about $6,000 |
| New slab and reinstated plumbing | about $8,000 |
| Total, 600 sq ft lowered 2 ft | $62,900 |
Around $62,900 all in. Note that the underpinning itself is roughly 60% of the total — everything else is the work around it.
The permit, which costs less than you think
The City of Toronto's underpinning permit fee is$11.89 per linear metre plus a $206.53 minimum. On a typical house that comes to under $400.
Contractors generally bill $2,000 to $3,000 for permits. That is not the City taking $3,000 — it is the cost of preparing the application, coordinating with the engineer, and attending inspections. Worth knowing so you can read the line item correctly rather than assuming it is a municipal charge.
Why quotes are so hard to compare
Contractors in this market quote against different denominators — linear feet of wall, square feet of finished floor, or square feet of excavated face. Applied to one identical basement those produce totals differing by more than $100,000.
Before you compare any two underpinning quotes, readhow underpinning is priced per linear foot. It is the single most useful thing on this site for someone holding two quotes.
The cheaper alternative
Bench footing typically costs 20 to 40 percent less, often $15,000 to $30,000 less on a full basement, because the original footing is never undermined.
The trade is permanent floor area: one to two feet along every exterior wall. In a wide basement that is a good deal. In a narrow Toronto semi it can eliminate the reason you were lowering the floor. The comparison is onbench footing.
And the method itself, including sequencing, permits and party-wall issues on semis, is onbasement underpinning in Toronto.