Benching vs Underpinning: Which One’s Right in Toronto?
If you’ve got a basement that’s too short to stand up in, or you want to turn it into livable space, you’ve probably heard two terms thrown around: underpinning and benching.
Both can help you lower your basement floor and gain ceiling height, but they’re very different methods, with different costs, uses, and risks.
In this article, we’ll break them both down in plain English, so you can understand exactly what each one does, when to use it, and how to avoid a basement renovation disaster.
The Short Answer
- Underpinning digs under your existing footings and pours new, deeper ones. You keep the full floor area and can go deeper. It costs more and takes longer.
- Benching (bench footing) leaves the old footings alone and pours a concrete ledge inside the walls. It’s cheaper and simpler, but the ledge takes floor space and limits how deep you can go.
- In Toronto, both are permit jobs. The City’s permit list covers basement work that excavates or builds foundations, and it names underpinning outright.
- Planning a legal basement unit? Ontario requires a 1.95 m (6′ 4¾”) ceiling over the unit’s whole required floor area. That usually decides the method for you.
Basement Underpinning
Underpinning is the process of digging below your existing foundation to extend it deeper into the ground.
Basically, you’re lowering the basement floor by lifting the whole house’s support system further down.
It’s like giving your home new, longer legs—but without moving it.
Here’s how it works:
- Contractors dig sections beneath the footing
- Pour new concrete below the old base
- Repeat the process around the entire perimeter.
- Once complete, the basement floor can be dug out several feet lower, giving you more headroom.
This method is often used when you want to maximize ceiling height and increase the value of your home by turning a crawl space or low basement into a fully finished space.
Pros of Basement Underpinning
- More Height, More Space: You can often get a full 8- to 9-foot ceiling height, making your basement feel like a main floor.
- Stronger Foundation: If done right, it strengthens the home’s structure and may fix existing settlement issues.
- Increases Home Value: More livable space means more resale value, especially in cities like Toronto where square footage is gold.
- Allows for Walkouts: You can create basement walkouts or secondary suites more easily.
Cons of Basement Underpinning
- More Expensive: It’s usually the most costly option due to labour, engineering, and permits.
- Takes Longer: Because the process is more invasive and done in stages, it can take several weeks to complete.
- Requires Engineering: You’ll need drawings, permits, and inspections from the city—and a professional structural engineer.
Basement Benching
Benching, also called a bench footing, is a way to lower the basement floor without touching the original foundation. Instead of digging under the existing footings, contractors create new concrete walls inside the old ones, sloped out like a bench—hence the name.
Picture it like this: you dig down inside your basement, but instead of undermining the old footing, you pour an angled concrete ledge around the inside perimeter. The original foundation stays put. The bench becomes the new support wall.
This method is often used when underpinning is too expensive, too risky, or simply not necessary.
Pros of Basement Benching
- More Affordable: No digging under your home’s foundation means less labour and lower risk, so the cost is usually much lower than underpinning.
- Faster Project Timeline: Because it’s simpler, jobs can often be completed in half the time.
- No Need to Disturb Footings: Great for older homes with fragile foundations, or when engineering limitations prevent underpinning.
Cons of Basement Benching
- Takes Up Space: The bench itself is bulky and sticks out from the walls, taking up precious square footage—sometimes 12 to 24 inches around the perimeter.
- Less Headroom Gain: You’re limited in how far down you can go, since you have to stay above existing footing depth.
- May Affect Resale Value: Some buyers may see benches as a downside, especially if the goal is a clean, open basement layout.
What Is Right For You?
So how do you decide between underpinning and benching? It depends on your goals, your budget, and your house.
Here’s a quick breakdown:
| Goal | Best Option |
|---|---|
| Maximize ceiling height | Underpinning |
| Keep project affordable | Benching |
| Add a legal rental suite | Underpinning (usually required by code) |
| Avoid touching the foundation | Benching |
| Increase home resale value | Underpinning |
| Work around old/cracked foundations | Benching |
Also, keep in mind: local building codes matter. In places like Toronto, basement apartments require minimum ceiling heights, separate entrances, and sometimes fireproofing—all of which are easier to achieve with underpinning.
Still unsure? This isn’t a decision you want to guess on. A structural engineer or licensed contractor can inspect your foundation and tell you what’s realistic, safe, and legal.
Underpinning vs Benching Side by Side
| Underpinning | Benching (bench footing) | |
|---|---|---|
| What changes | New footings poured below the old ones, in stages | Concrete ledge poured inside the old walls; old footings untouched |
| Floor area | Kept. Walls go straight down | Lost around the edge, often 12 to 24 inches deep |
| How deep you can go | Deeper. Set by the engineer’s design | Limited, because the bench has to protect the old footing |
| Engineering | Toronto requires engineer testing at the first and last stages on every underpinning job | Plan on engineered drawings too, since you’re building a new foundation element |
| Building permit | Yes | Yes (excavating or building foundations) |
| Best fit | Legal basement units, full-height living space, walkouts | Storage, rec rooms, budgets where floor space matters less |
How Much Floor Space Does a Bench Take?
People underestimate this. A bench runs around the whole perimeter, so a strip that looks small on one wall adds up.
Take a basement that’s 25 by 40 feet inside the walls, or 1,000 square feet. An 18-inch bench on every wall leaves you 22 by 37 feet, or 814 square feet. That’s 186 square feet gone, close to a fifth of the room. You can stand on a bench, but you can’t put a couch against the wall where it is.
Underpinning keeps the walls where they are, so the 1,000 square feet stay usable from edge to edge.
The Ceiling Height Rule for a Legal Basement Unit
If the goal is a rental unit or in-law suite, start here.
Ontario’s guide to second units says a basement unit can have a ceiling of 1.95 m (6′ 4¾”) over the entire required floor area, including the route inside the unit to the exit (Building Code, Division B, Table 11.5.1.1.C). Measure from the finished floor to the finished ceiling, after flooring, insulation and any drop ceiling are in.
So a basement that measures 6 feet 6 inches today, bare concrete to joists, can still come up short once it’s finished. Lowering the floor is how most older Toronto houses get there. Underpinning keeps the full floor area at that height. With a bench, the floor area next to the walls is the ledge, so check with your designer whether the remaining space still meets the unit’s required room sizes.
What Toronto Asks For Before You Dig
For underpinning, the City of Toronto’s application guide asks for:
- A site plan from a current survey, showing property lines and the distance to neighbouring buildings
- Foundation plans showing where you’ll underpin, the numbered stages of the work, and the lineal metres of underpinning
- Cross sections showing the footings, the depth of underpinning, and floor-to-ceiling heights
- Floor plans of every level, including smoke and carbon monoxide alarms and plumbing fixtures
When an engineer must design it. If your new footing goes below the level of a neighbouring building’s footing, and inside what the City calls the angle of repose (the slope at which the soil stays stable), a Professional Engineer has to design the work and review it on site. That’s common in semi-detached houses and row houses, where the neighbour’s foundation sits right next to yours.
Testing on every job. Even when an engineer doesn’t have to design it, Toronto requires testing and reports by a Professional Engineer at the first and last stages of construction before the work passes inspection.
Faster permits for simple jobs. Basement walkouts and underpinning go through the City’s Express Services stream for houses with no more than two units and no active permit for a new building or addition. The City says an examiner reviews a complete application within 3 days, and the permit is usually issued within one business day after you pay the fee. Missing documents send the application back, so a complete package saves the most time.
For permits beyond the basement, see our guide to Toronto demolition permits.
Is Underpinning Risky?
It can be, if it’s rushed. Underpinning removes soil from under a wall that’s carrying the house, so the risks are real:
- Digging too much at once. That’s why the work is done in short sections, one stage at a time, and why the City wants the stages numbered on the drawings.
- Undermining the neighbour. Digging below a neighbour’s footing inside the angle of repose can move their foundation as well as yours. That’s where the engineer rule comes from.
- Water. A deeper floor sits closer to the water table, so drainage, waterproofing and the sump need planning before the floor is poured.
Benching carries less of this risk because it never goes under the old footing. That’s the main reason people choose it for older houses with fragile foundations.
Can You Use Both in One Basement?
Yes. Some projects underpin one or two walls and bench the rest. For example, you might underpin the wall where a walkout or bedroom needs full height and bench a wall that will end up behind storage. The engineer decides wall by wall, based on the footings, the soil and what’s next door.
Will Lowering the Floor Fix a Damp Basement?
Not by itself. A lower floor can be a wetter floor if water isn’t handled. The good news is that the floor is open anyway, so it’s the cheapest moment to add or replace weeping tile, a sump pit and a backwater valve, and to waterproof the walls you’ve just exposed. Ask for these as line items in the quote, so you can see what’s included.
Is Underpinning the Same as Piling?
No. Piles (including helical piles) are driven or screwed deep into the ground to carry a foundation’s load. They’re used more for repairing settlement and for new additions than for lowering a basement floor. Lowering a floor in a Toronto house is normally done with staged concrete underpinning or a bench footing.
What Drives the Cost
We don’t publish one price, because two basements on the same street can be very different jobs. These are the factors that move a quote:
- Lineal metres of wall being underpinned (the City asks for this figure on the drawings)
- How deep you’re going
- Soil and water found once digging starts
- Access: every bucket of soil has to come out, and a tight side yard is slower than a walkout
- Neighbouring foundations: work inside the angle of repose needs an engineered design
- What’s bundled: permits, engineering, waterproofing, drainage, new slab, and any asbestos or old insulation that has to come out first
Benching usually costs less for the same basement because the digging is shallower and nothing goes under the footing.
How to Choose the Right Contractor
Lowering a basement is not a DIY job. Get the wrong crew, and you could end up with:
- Cracked foundation
- Leaking basement
- Lawsuit from your insurance company
- Failed city inspection
Here’s what to look for in a contractor:
- Structural Insurance: Most demo or reno companies don’t carry it. If something goes wrong, you could be paying out of pocket. Don’t take the risk.
- Proper Licensing & Permits: They should be registered to do basement lowering in your city or region.
- Experience with Both Methods: A contractor who only does benching might steer you in that direction, even if it’s not best for your home.
- Hazard Material Certification: If there’s any chance of asbestos or mold (common in older basements), your contractor should be certified to deal with it safely.
- References and Finished Projects: Always ask to see completed jobs and talk to past customers.
What both quotes should spell out
Get two or three quotes, and make sure each one lists:
- The method (underpinning, benching or a mix) and the planned new floor depth
- Who prepares the drawings and who pays for the engineer’s site reviews and testing
- Who applies for the building permit
- The number of stages, and roughly how long each takes
- Drainage, sump, backwater valve and waterproofing: included or extra
- Soil removal and disposal
- What happens if they find something unexpected, like water, rock or asbestos
- Proof of insurance
If two quotes are far apart, it’s usually because one of them leaves out items on this list.
Older basements often have asbestos in pipe wrap, tile or insulation. If testing finds it, it has to come out properly before anyone cuts or digs. See our abatement service.
Benching and Underpinning: Common Questions
Do I need a permit for a bench footing in Toronto?
Yes. Toronto’s permit list covers basement work that excavates or builds foundations, and a bench footing is a new foundation element. Underpinning is named on the list directly.
Do I need an engineer?
For underpinning, Toronto always requires engineer testing and reports at the first and last stages. A full engineered design is required when the new footing goes below a neighbour’s footing within the angle of repose.
How high does a legal basement unit’s ceiling need to be?
Ontario’s guide for second units says 1.95 m (6′ 4¾”) over the unit’s entire required floor area, including the route to the exit.
Which adds more value?
Underpinning, in most cases, because you keep the whole floor and can reach legal unit height. Benching gives you height without that full-width floor.
Can benching be changed to underpinning later?
It means removing the bench and doing the underpinning work you skipped, so it’s rarely worth planning that way. Decide what the basement is for before you choose.
Is a bench as strong as underpinning?
When it’s designed and built correctly, both support the house. They do it differently: underpinning extends the foundation down, while a bench braces the existing footing from the inside.
To see how we run these projects, visit our basement underpinning service.
Underpinning Experts in Toronto
If you think underpinning might be the right solution for your basement, we’re here to help.
We offer free consultations to assess your foundation, ceiling height, and structural conditions. No pressure, no guesswork—just straight answers from trained professionals.
If underpinning is the right choice, we’ll take care of it from start to finish. We’re fully licensed, structurally insured, and carry all required certifications to work with complex foundations and hazardous materials.
We’ve done underpinning jobs all over Toronto and the GTA—from single-family homes to multi-unit conversions. Whether you’re trying to gain more space, build a rental suite, or fix a failing foundation, we’ll make sure the job is done safely, legally, and cleanly.