- Published: January 9, 2026
Nico Barbieri
Nico was the first person hired for the position of estimator and project manager for our growing company. He has over 25 years of experience in the water proofing industry. More About Nico
You’ve decided you want more headroom in your basement. Maybe you’re planning a legal rental suite, a home gym, or simply a space where you can actually stand upright without ducking under ductwork. Whatever the goal, you’ve probably come across two options: bench footing and underpinning.
They both lower your basement floor. They both require professional installation. But they work differently, cost differently, and produce different results — and choosing the wrong one for your home can cost you thousands of dollars or leave you with a basement that doesn’t meet your actual needs.
What Is Underpinning?
Underpinning is a structural process that extends the depth of your existing foundation by excavating beneath the current footings and pouring new, deeper concrete footings below them. This allows the entire basement floor to be lowered uniformly — typically by 24 to 36 inches — without reducing the usable floor area of the space.
It is a complex, engineered process. The excavation happens in carefully sequenced sections — typically 3 to 5 feet at a time — so the house remains structurally supported throughout. Jumping from one section to an adjacent one before the concrete has cured is one of the most dangerous mistakes in basement lowering, which is why professional engineering oversight is mandatory.
How Underpinning Works — Step by Step
- Structural engineering assessment — A licensed professional engineer assesses your foundation, soil conditions, and the depth of excavation needed. Sealed drawings are prepared and submitted with your permit application.
- Building permit obtained — Work cannot legally begin before the permit is issued.
- Basement floor removed — The existing concrete slab is broken up and removed.
- Staged excavation beneath footings — Sections of soil under the existing footings are removed, one small section at a time, in a specific sequence to maintain structural stability.
- New footings poured — New concrete footings are poured at the greater depth, extending the foundation vertically.
- Process repeated — This continues around the entire perimeter until all sections are complete.
- New concrete floor installed — Once all footings are set and inspected, a new floor slab is poured across the full basement area.
- Waterproofing and drainage — Strongly recommended at this stage, since the foundation walls are already exposed. Interior waterproofing and a new sump pump or weeping tile system should be installed before the new floor is poured.
- Inspections — The City requires professional engineer field reviews at the first and last stages of construction at minimum.
What Is Bench Footing?
Bench footing (also called benching or bench pinning) lowers your basement floor without modifying the existing foundation footings at all. Instead, the floor is excavated inward from the existing walls, and a concrete “bench” or ledge is constructed around the perimeter of the basement to support the original footings at their current depth. The new, lower floor is poured in the central area, while the bench provides the structural support the existing foundation requires.
The result is a lower floor — but with a step-down bench running along all four walls, typically 18 to 24 inches wide depending on the depth of the excavation.
How Bench Footing Works — Step by Step
- Assessment — Structural engineer or experienced contractor assesses foundation condition and determines whether bench footing is appropriate for the depth of lowering needed.
- Permit obtained — A building permit is required in Toronto, along with engineering drawings. Both methods require this step.
- Basement floor removed — Existing slab is broken up and removed.
- Interior excavation — The floor area is dug down to the new lower level. Unlike underpinning, excavation stays away from the existing footings.
- Perimeter bench constructed — A concrete bench is built along all walls, extending from the base of the existing footings down to the new floor level.
- New floor poured — The lower central floor is poured, with the perimeter bench forming the structural border.
- Waterproofing and drainage — As with underpinning, this is the right moment to address waterproofing. Foundation crack repair and interior drainage systems should be installed before the new floor is poured.
- Inspections
Bench Footing Vs Underpinning Side-by-Side Comparison
| Feature | Underpinning | Bench Footing |
|---|---|---|
| How it works | New footings poured below existing ones | Concrete bench supports existing footings |
| Excavation location | Beneath foundation walls | Inside basement only |
| Depth possible | 24–36 inches typically | Best for 6–12 inches |
| Floor space result | Full usable floor area | Reduced — bench takes 18–24″ per wall |
| Cost (structural work) | $80–$150 per sq. ft. | $40–$70 per sq. ft. |
| Typical full project cost | $60,000–$100,000+ | $30,000–$60,000 |
| Permit required (Toronto)? | Yes — always | Yes — in Toronto |
| Engineering drawings required? | Yes — mandatory | Yes — required in Toronto |
| Timeline (structural phase) | 4–8 weeks | 3–5 weeks |
| Permit approval (City of Toronto) | 6–12 weeks | 4–8 weeks |
| Legal suite eligible? | Yes — if target height achieved | Possible but less likely |
| Resale value impact | High — 80–90% ROI with finished suite | Moderate |
| Best suited for | Legal suites, full renovations, maximum headroom | Budget-conscious height gain, stable foundations |
2026 Cost Breakdown: What You'll Actually Pay in Toronto
The current blog pricing is outdated. Here are the accurate 2026 figures based on current market rates and City of Toronto data.
Underpinning — Full Cost Breakdown
| Cost Item | 2026 Toronto Range |
|---|---|
| Structural underpinning work | $80–$150 per sq. ft. |
| Typical 600 sq. ft. basement (structural only) | $48,000–$90,000 |
| Structural engineering drawings | $2,000–$7,000 |
| City of Toronto building permit | $400–$900 (city fees) + engineering = ~$2,000–$3,000 total |
| New concrete floor | $2–$6 per sq. ft. |
| Waterproofing (recommended at same time) | $3,000–$10,000 |
| Full project including engineering, permit, floor | $60,000–$100,000+ |
| With full basement renovation (suite, finishes) | $120,000–$200,000+ |
Bench Footing — Full Cost Breakdown
| Cost Item | 2026 Toronto Range |
|---|---|
| Bench footing work | $40–$70 per sq. ft. |
| Typical 600 sq. ft. basement | $24,000–$42,000 |
| Engineering drawings | $1,500–$4,000 |
| City of Toronto building permit | $400–$900 (city fees) |
| New concrete floor | $2–$6 per sq. ft. |
| Waterproofing (recommended) | $3,000–$10,000 |
| Full project including engineering, permit, floor | $30,000–$60,000 |
Which Method Is Right for Your Home?
Work through these questions honestly before deciding:
What is your primary goal?
Creating a legal basement apartment or rental suite? You need full ceiling height — a minimum of 1.95m (approximately 6’5″) per Ontario Building Code for habitable rooms. If your current basement is under 6’5″, bench footing may not get you there. Underpinning is almost certainly the right method.
Adding headroom for a gym, playroom, or storage upgrade? If you only need 6–12 inches of additional height and the bench won’t significantly impact your planned use, bench footing is a practical and cost-effective choice.
Maximising floor space for an open-plan living area or home theatre? The perimeter bench from bench footing can frustrate furniture placement and design options. Underpinning gives you an unobstructed rectangular floor.
What is your realistic budget?
Underpinning is a meaningful investment — $60,000–$100,000 for the structural phase of a standard Toronto home, before any finishing work. If you’re planning to fully renovate and create a legal suite, the return on investment is strong. If your goal is modest, bench footing at $30,000–$60,000 may serve you better.
What condition is your foundation in?
If your foundation shows signs of structural issues — horizontal cracking, bowing walls, settlement — underpinning may actually be necessary regardless of your headroom goals, because the process allows for structural reinforcement at the same time.
If your foundation is in sound condition, bench footing carries lower structural risk by leaving the existing footings undisturbed.
Are you combining this project with waterproofing?
This is something many homeowners miss — and it’s important. Since both underpinning and bench footing expose your foundation walls and floor, this is the optimal time to install or upgrade your interior waterproofing system, replace failed weeping tile, and upgrade your sump pump. Doing it later means reopening the finished floor — a far more expensive disruption.
At Aquatech, we include waterproofing as part of our basement lowering projects precisely because this is when it makes the most economic sense.
Ready to explore your options?
Contact us today for a free consultation and let our specialists help you determine the best solution for your foundation—and your budget.
Frequently Asked Questions
In most cases, yes. The basement is inaccessible during the structural phase, but the rest of the home remains habitable. If you have young children or pets, the dust and vibration may be disruptive — some families choose to stay elsewhere for the first week or two of heavy excavation.
Yes. Both underpinning and bench footing require a building permit and engineering drawings in the City of Toronto. Working without a permit risks fines, mandatory demolition orders, and serious complications when you try to sell your home. Never start either project without a permit in hand.
For underpinning: allow 6–12 weeks for permit approval, plus 4–8 weeks for structural work. Total: 3–5 months from contract to structural completion, before any interior finishing begins. For bench footing: 4–8 weeks for permit, plus 3–5 weeks for structural work.
Clay soil is found throughout the GTA and affects both methods — but underpinning in clay soil specifically requires a professional engineer’s sealed drawings and field reviews under City of Toronto requirements. This adds to the cost and timeline but is non-negotiable. An experienced contractor who works in Toronto clay soil regularly is essential.
Bench footing works best for modest height gains (6–12 inches) on sound, stable foundations. If your foundation has structural issues, if you need more than 12 inches of depth, or if you’re creating a legal suite where usable floor space matters, underpinning is typically the better choice.
A finished basement with a legal secondary suite typically recovers 80–90% of the total investment in property value. In high-demand Toronto neighbourhoods — particularly semi-detached and detached homes — the rental income alone can significantly offset the project cost over time. Underpinning without finishing is an investment in potential; underpinning combined with a legal suite conversion is an investment in both livable space and income.
Yes. Aquatech manages the full scope — structural assessment, permit coordination, underpinning or bench footing, interior waterproofing, sump pump installation, and concrete floor installation. Doing everything with one licensed contractor eliminates coordination risk and ensures the waterproofing is properly integrated with the structural work. Every project is backed by our 25-year transferable warranty.
Underground surprises are part of any basement lowering project — old buried debris, unexpected soil conditions, or foundation issues that weren’t visible before excavation. A transparent contractor will identify these early and discuss scope and cost adjustments before proceeding. Be cautious of any contractor who won’t discuss what happens when unexpected conditions arise.
