Underpinning a basement in Toronto requires a building permit, and the permit will not be issued without stamped structural drawings from a licensed Ontario engineer. The City fee is $11.89 per linear metre of wall being underpinned with a minimum charge, which puts most houses between $400 and $900. Engineering typically adds $1,500 to $2,500.
The part that surprises people is not the cost. It is the wait: permit approval currently takes 6 to 12 weeks before a crew can start.
Get a real range
Not a brochure. Tell us the basics and we will come back with numbers that reflect your actual foundation.
Plan the permit timeline before you plan the renovation. A homeowner who books a contractor for next month, without a permit in hand, is booking a delay.
What the permit package must contain
Stamped structural drawings. Prepared and sealed by a professional engineer licensed in Ontario. This is a design document, not a contractor sketch. It specifies footing depths, section widths and reinforcement.
The underpinning sequence plan. The specific order in which sections are excavated and poured, so the house is continuously supported. This sequence is the engineering, and it is why the work takes weeks rather than days.
Site and structural details showing existing conditions and proposed depths.
Agreement to staged inspections. Inspections happen during the work at defined stages, not only at completion.
The realistic timeline, end to end
| Stage | Typical duration |
|---|---|
| Engineer site visit and drawings | 1 - 3 weeks |
| Permit application review by the City | 6 - 12 weeks |
| Underpinning work on site | 4 - 6 weeks |
| Slab cure before finishing | 1 - 2 weeks |
| Total, first call to finished basement | 3 - 6 months |
Most quotes describe only the 4-6 week middle row. That is not dishonest, it is just the part the contractor controls, but it is why homeowners are repeatedly caught out by the real calendar.
Why the sequencing rule exists
The house does not stop being supported while its foundation is rebuilt. Underpinning works by excavating alternating sections, typically three to four feet wide, pouring each one, letting it cure, and only then moving to the adjacent section. The undisturbed sections carry the load while their neighbours are open.
Skipping or compressing that sequence is the failure mode that causes settlement, cracking and worse. It is also invisible to a homeowner watching from the top of the stairs, which is precisely why the sequence is specified on stamped drawings and verified by inspection.
What we do and do not do
We coordinate the permit process and work with licensed structural engineers who prepare and seal the drawings. We do not perform structural engineering ourselves and do not hold a professional engineering licence. The engineer's seal comes from the engineer, and their independence is a protection for you, not a formality.
Common questions
Do I need a permit to underpin my basement in Toronto?
Yes. Underpinning alters the structural foundation, so a building permit is required, and it will not be issued without stamped drawings from a licensed Ontario structural engineer.
How much is the underpinning permit fee in Toronto?
The City charges $11.89 per linear metre of wall being underpinned, subject to a minimum. In practice most homeowners pay $400 to $900 to the City. Contractors commonly quote permits and engineering together as a $2,000 to $3,000 combined line item.
How long does permit approval take?
Currently 6 to 12 weeks in Toronto. Add 1 to 3 weeks before that for the engineer's site visit and drawings, so plan on 2 to 4 months before work begins.
Can I underpin without a permit?
No. Beyond the safety issue, unpermitted structural work surfaces at resale, can void insurance coverage, and can trigger orders to remedy. It also removes the inspection process that protects you from a crew cutting corners on sequencing.
Who hires the engineer, me or the contractor?
Either arrangement is common. What matters is that the engineer is licensed in Ontario, seals the drawings, and is available for the staged inspections.
What happens during inspections?
A City inspector, and often the engineer, verifies the work at defined stages, checking that the sequence, depths and reinforcement match the approved drawings. Failing an inspection stops work until it is corrected.
Does benching need a permit too?
Yes. Bench footing is also structural work requiring a permit and stamped drawings, even though the original footing is left undisturbed.
Get a real range
Not a brochure. Tell us the basics and we will come back with numbers that reflect your actual foundation.