If you own an older home in Toronto, you've probably stood in your basement and felt it: ceilings at six feet or so, ductwork grazing your head, a space that's fine for storage and not much else. Most of the city's century homes were built when a basement was a place for the furnace and the coal — not a rec room, a rental suite, or an ADU. The lot is fixed, the zoning is what it is, and you can't easily go up. For many Toronto homeowners, down is the only direction left to gain real living space.
There are two established ways to lower a basement floor: underpinning and bench footings (also called benching). Both are legitimate, both need engineering and a building permit, and they trade off cost against usable space in very different ways. Here's what clients should know before getting quotes.
What underpinning is
Underpinning extends your existing foundation deeper into the ground. Working in short, alternating sections — never the whole wall at once — the contractor excavates beneath the existing footing, pours a new concrete foundation segment below it, and repeats in a staged sequence until the entire perimeter sits on new, deeper footings. Then the floor is excavated to the new level and a new slab is poured, usually with new weeping tile and waterproofing while everything is open.
Pros: You gain the full floor area of your basement at the new, deeper level — wall to wall, no lost space. Finished ceiling heights of eight feet or more are achievable. It's also the natural moment to fix drainage, waterproofing, and old plumbing, and a full-height basement adds real resale value, especially where a legal secondary suite is the goal.
Cons: It's the more expensive option, because the work is structural, staged, and labour-intensive. It takes longer — typically several weeks to a few months depending on the house. And because you are literally rebuilding what the house stands on, the quality of the engineering and the sequencing matters enormously. This is not a place for the lowest bid without checking who designed and reviews the work.
What bench footings are
Bench footings take a different approach: instead of going under the existing foundation, the new lowered floor stops short of the walls, and a sloped or stepped concrete "bench" is poured against the base of the existing foundation around the perimeter. The bench braces the original footing, which stays exactly where it is — the new, deeper floor simply sits inside it.
Pros: It's meaningfully cheaper and faster than underpinning, because nobody is excavating beneath your footings. The structural risk during construction is lower, and it can be a smart choice where a neighbouring structure is very close, where soil conditions make underpinning difficult, or on a shared party wall where full underpinning would need the neighbour's participation.
Cons: The bench eats your floor area. Around the entire perimeter you lose a strip of usable space — commonly a foot or two at the floor, depending on how deep you're going — and the deeper you lower, the wider the bench gets. In a typical narrow Toronto semi, that perimeter strip is a real bite out of an already modest footprint. Benches also complicate framing, built-ins, and furniture placement, and buyers notice them.
Underpinning buys you the whole floor. Benching saves you money by giving some of that floor back. The right answer depends on what the space is for.
The Toronto reality: lowering is often the only option
In much of Toronto's older housing stock — the Victorians, Edwardians, and wartime bungalows — basement ceiling heights simply don't meet what the Ontario Building Code requires for livable space. If your goal is a legal secondary suite, a garden-suite-supporting layout, or just a family room where adults can stand comfortably, raising the house is rarely practical and adding up or out is often blocked by cost or zoning. Lowering the basement is frequently the only realistic path to more livable square footage on your existing lot, which is exactly why underpinning has become such common work across the city.
Which one is right for you?
A rough guide from our practice: if the basement will become a rental suite or primary living space, the lost perimeter area from benching often costs you more in function and value than underpinning costs in dollars — full underpinning usually wins. If you're chasing headroom on a tight budget for your own family room, or site conditions make underpinning risky, bench footings can be the pragmatic answer. Many projects also mix the two: underpin the walls where space matters, bench where it doesn't, or bench along a shared party wall only.
Either way, the process is the same: an engineer assesses your existing foundation and soil, designs the underpinning or bench in a staged sequence, and seals the drawings your contractor submits for the building permit. The City will require engineered drawings for this work — it's not optional, and it protects you.
Thinking about lowering your basement? Send us a few photos and your rough goals, and we'll tell you honestly which approach fits — before you commit to either.