How Much Does Underpinning Cost in Ontario?
Underpinning costs in Ontario range from $500 – $800 per lin. ft. Prices vary by scope, city, and site conditions.
$500
Starting price
6-12 weeks
Timeline
15%
Recommended contingency
Written by Pavel Vysotckii
BCIN-certified building designer & Quantity Surveyor · Updated June 2026
Underpinning Cost Breakdown
| Scope | Low | High | Unit | Labour | Material |
|---|---|---|---|---|---|
| Excavation + underpinning piers (per linear foot) | $500 | $800 | per lin. ft | 65% | 35% |
| Full basement lowering, all-in (typical Toronto semi) | $75,000 | $150,000 | per project | 60% | 40% |
| Per-square-foot equivalent (basement floor area, same scope) | $80 | $160 | per sq ft | 60% | 40% |
| Geotechnical investigation + soil report (borehole) | $2,500 | $5,000 | per project | 85% | 15% |
| Structural engineering (design, stamped drawings, field reviews) | $3,500 | $8,000 | per project | 85% | 15% |
| Building permit fees | $1,500 | $4,000 | per project | 80% | 20% |
| Backwater valve (supply + install) | $2,000 | $4,000 | per valve | 60% | 40% |
| Sump pit + pump with battery backup | $1,500 | $3,500 | per system | 55% | 45% |
| Interior weeping tile (full perimeter) | $2,500 | $6,000 | per project | 55% | 45% |
| Foundation waterproofing on new walls | $3,000 | $8,000 | per project | 60% | 40% |
| New concrete floor slab (vapour barrier + reinforcement) | $6,000 | $12,000 | per project | 55% | 45% |
| Helical pile underpinning (per pile, 8-12 needed) | $1,200 | $2,000 | per pile | 55% | 45% |
| Optional: basement walkout entrance | $15,000 | $30,000 | per walkout | 60% | 40% |
| Optional: egress window + well (cut-in) | $2,500 | $6,000 | per window | 60% | 40% |
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Depth gained
Method
Common add-ons
Estimated total
$77,800 – $108,200
$560–$740 per lin ft × 130 ft
Engineering & permits (~$5,000–$12,000 combined) are included in these totals.
Book your walkthroughIllustrative estimate — soil, access, and scope move the number; book a free walkthrough for a fixed milestone price.
Price Ranges at a Glance
Excavation + underpinning piers (per linear foot)
Full basement lowering, all-in (typical Toronto semi)
Per-square-foot equivalent (basement floor area, same scope)
Geotechnical investigation + soil report (borehole)
Structural engineering (design, stamped drawings, field reviews)
Building permit fees
Backwater valve (supply + install)
Sump pit + pump with battery backup
Interior weeping tile (full perimeter)
Foundation waterproofing on new walls
New concrete floor slab (vapour barrier + reinforcement)
Helical pile underpinning (per pile, 8-12 needed)
Optional: basement walkout entrance
Optional: egress window + well (cut-in)
What's Included vs Not Included
Typically Included
- Structural engineer design and stamped drawings
- Building permit application and fees
- Temporary shoring and bracing
- Excavation in alternating 4-ft sections
- Concrete footings (25-32 MPa) with #15M rebar
- New basement floor slab with vapor barrier
- Interior weeping tile and sump pump
- Basic exterior waterproofing
- Building inspections at key stages
Not Included (Extra Cost)
- Basement finishing (framing, drywall, flooring)
- HVAC relocation and ductwork modifications
- Electrical panel relocation
- Plumbing rough-in for new bathroom
- Exterior landscaping restoration
- Window well installation and enlargement
- Geotechnical soil report ($2,500-$5,000)
- Heated enclosures for winter work
Underpinning Cost by City
Prices adjusted for local labour rates and material costs across 15 GTA cities.
| City | Low | High | vs Toronto | Details |
|---|---|---|---|---|
Toronto City of Toronto | $500 | $800 | 0% | View |
Mississauga Peel Region | $474 | $758 | -5% | View |
Brampton Peel Region | $461 | $737 | -8% | View |
Vaughan York Region | $485 | $776 | -3% | View |
Markham York Region | $482 | $771 | -3% | View |
Richmond Hill York Region | $480 | $768 | -4% | View |
Aurora York Region | $469 | $750 | -6% | View |
Oakville Halton Region | $510 | $816 | +2% | View |
Burlington Halton Region | $478 | $766 | -4% | View |
Milton Halton Region | $461 | $737 | -8% | View |
Ajax Durham Region | $452 | $724 | -9% | View |
Pickering Durham Region | $461 | $737 | -8% | View |
Oshawa Durham Region | $441 | $705 | -12% | View |
Whitby Durham Region | $449 | $718 | -10% | View |
Hamilton City of Hamilton | $447 | $716 | -10% | View |
Permit & Engineering Costs
Building Permit (Foundation Alteration)
City of Toronto or local municipality
Requires structural engineer drawings and stamped underpinning plan. Permit cost is based on project value (typically 0.5-1% of construction cost).
$800-$2,500
Engineered Drawings
Professional Engineer (P.Eng) licensed in Ontario
Engineer specifies concrete strength, rebar schedule, excavation sequence, shoring requirements, and soil bearing assumptions. Site visits during construction are often included.
$3,500-$8,000
Plumbing Permit (if relocating drains)
City plumbing inspector
Required if you're lowering floor drains, relocating the sump pit, or tying into the main sewer stack.
$150-$400
Money-Saving Tips
Full lowering works out to roughly $80-$160 per square foot of basement area on a typical Toronto semi — beware quotes using a different scope, because per-square-foot numbers only compare if they cover the same work.
As a Quantity Surveyor, the first thing I check on a quote is the scope line. Published Toronto underpinning prices run anywhere from $50 to $450 per square foot because some figures are a dig-and-pour structural shell while others include a fully finished, rentable basement — the two are not comparable.
Depth and access drive the spread: every extra foot of lowering means more excavation, deeper piers, and more soil out the door — and a zero-lot-line semi where soil leaves by conveyor through the house costs more per foot than a detached home with side-yard machine access.
Soil conditions move the price too. Dense Toronto clay holds an excavation face better than sandy fill or a high water table, which can force shorter pier sequences, dewatering, and design changes — this is what the geotechnical report prices out before you commit.
If one bid is $30,000 lighter, read the exclusions before celebrating — slab, weeping tile, waterproofing, engineering, and HST are the lines most often missing from a low quote.
Get the geotechnical report — at $2,500-$5,000 it's cheap insurance for a $100K+ project.
Bundle waterproofing with underpinning to save 30-40% vs doing them separately.
Avoid winter work if possible — heated enclosures add $3,000-$8,000.
Plan all mechanical relocations before starting — mid-project changes during underpinning are extremely expensive.
Compare bench underpinning vs helical piles — piles are faster but limit future foundation modifications.
Related Cost Guides
Underpinning Cost FAQs
Can I underpin just one wall instead of the whole perimeter?
Yes, but only if that wall is structurally independent (e.g., an addition with its own footing). If it's part of the main foundation, underpinning one wall deeper than the others creates differential settlement — the deeper wall is now on stiffer soil, so the house rotates toward the shallow walls. You'll get cracks at the corners where the two elevations meet. If you're lowering the basement floor, you have to underpin the full perimeter because the interior slab bears on the soil and ties into all four walls.
How much basement height can I actually gain?
Most basement lowering projects gain 18-30 inches of headroom. You're limited by the depth of the joists above (you can't lower the floor into the joists) and the cost curve (every additional foot of depth adds $100-150 per linear foot). Going from 6'6" ceilings to 8'0" is common and makes the space livable for most people. Going to 9'0" is possible but expensive — you're excavating an extra 12 inches of soil and pouring thicker walls to handle the increased lateral pressure.
What's the difference between underpinning and benching?
"Benching" is just another name for bench underpinning — the method where you excavate alternating 4-ft sections, pour footings, cure, then do the skipped sections. Some contractors say "benching" to distinguish it from helical pile underpinning (which doesn't involve concrete pours). They're describing the same process.
Can I live in the house during underpinning?
Yes, but it's loud, dusty, and disruptive. Excavation happens in the basement, so you'll have workers, equipment, and concrete trucks on site for 6-12 weeks. If you have young kids or work from home, many homeowners move out for the duration. The main floor is safe to occupy (the shoring beams carry the load), but you'll have limited access to the basement and you may lose water/power for a day or two when they relocate plumbing and electrical.
Do I need a geotechnical report if I'm in Toronto (clay soil)?
Most of Toronto sits on Halton Till clay with a bearing capacity of 75-100 kPa, so many engineers design underpinning footings based on that assumption without a geotech report. BUT: if your property is near a ravine, on a hill, or was previously industrial land, you could have fill, sand lenses, or contaminated soil. A geotech report costs $2,500-$5,000 and eliminates the guesswork. If you're spending $100,000 on underpinning, spending 2.5-5% on soil testing is cheap insurance.
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