Basement Underpinning vs Bench Footing: Cost and Process

A basement too low to live in has two ways down. Underpinning digs under the house's footings in short sections and pours new, deeper ones. Bench footing reaches the same depth for less money by pouring a concrete step along the inside of each wall, and that step takes floor space. Which one suits your house comes down to how much floor you can give up.

Underpinning or bench footing: how each one lowers the floor

Both methods dig the floor below the old footings while keeping the house from moving. The difference is where the new concrete goes, under the old footings or beside them.

How underpinning works

Underpinning extends the foundation down. The crew digs out a short length under the existing footing, pours a new footing and wall section beneath it, and opens the next length only once that one holds. The lengths are dug out of order so that no long run of wall is left unsupported, and Toronto's underpinning permit guide asks for the stages on the drawings to be “numbered to show sequence of work”.

The new section is poured in one of three ways. A non-shrink pour leaves a gap of about 2 inches under the old footing that is packed with non-shrink grout; an overpour lets the new concrete overlap the old wall; a flush-with-the-wall pour forms an L-shaped section that widens at the bottom.

How bench footing works

Bench footing leaves the old footings where they are. The floor is dug down in the middle of the room, and a new footing and a concrete bench are poured along the inside of each wall, set back far enough not to disturb the soil carrying the old footing. The bench is the price of the saving: a Toronto firm's 2026 figures put the floor lost at 12 to 24 inches along each wall, and the deeper the dig, the further the bench reaches into the room.

What underpinning costs in 2026

Toronto basement firms price underpinning by the linear foot of wall lowered or by the square foot of floor, and one firm's 2026 per-square-foot figure includes the engineering, permits, waterproofing and new slab. That firm puts a full perimeter on a detached or semi-detached house at $60,000 to $120,000, and a second firm puts underpinning a 1,000 square foot basement at $60,000 to $100,000.

Depth, soil and water, access, the municipality's fees and what is bundled in move a quote within that range. A basement of 6 feet 2 inches taken to 8 feet costs more than one gaining six inches, and a detached house with side-yard access is cheaper to dig than a semi whose soil leaves through the front door.

Underpinning buys height, not finished space. Finishing the basement is priced on top, and a luxury Toronto firm puts underpinning plus finishing at $180,000 to $250,000 for 1,000 square feet.

Payments follow the stages, and an Ontario owner holds back 10% of the work's value as it is supplied, under the Construction Act, until the lien period has passed, so $9,000 of a $90,000 job stays back; BC and Alberta set the same 10%.

The ceiling height a basement suite needs

When underpinning is done for height, the number that counts is the code's minimum for a basement suite. Ontario's second-unit guide, BC's 2024 code and Calgary's suite rules land on the same 1.95 m for a basement suite in an existing house.

Ontario's guide to adding a second unit and Calgary's secondary suite rules both use 1.95 m, while BC's 2024 code allows its lower figures only where a suite is added to an existing house.

Height is only the first of the rules for a legal basement suite; fire separation, linked alarms, exits and bedroom windows follow once the floor is low enough. Underpinning can cost as much as building the suite itself, so price the two together. Many older Toronto basements are only 5 to 6.5 feet high, on one firm's 2025 figures, which is why underpinning comes up so often in basement renovations in Toronto.

Permits, engineers and inspections for underpinning

Toronto lists basement underpinning among the basement work that needs a building permit. Its underpinning guide requires a Professional Engineer to design the work and review it on site where the new foundation goes below a neighbouring building's footing within the soil's angle of repose, where the underpinning exceeds 1,200 mm of laterally unsupported height, or where the soil is clay or silt. In every case, an engineer tests and reports at the first and last stages before the work can pass inspection.

The drawings show the stages in digging order, the lineal metres and depth of underpinning, any support columns, and the distance to and depth of neighbouring footings. For a house with no more than two units, underpinning is on the list for Toronto's Express Services, which aim to review eligible applications within 3 business days of intake.

Out west, Calgary requires a building permit for structural changes and for a basement developed for the first time, and Edmonton asks for engineer-stamped drawings where structural changes are included. Vancouver's renovation fast track excludes projects that need structural alterations, so underpinning there takes the regular permit path.

Finishing afterwards is a separate question. Toronto needs no permit for finishing a basement that makes no structural or material alterations, adds no second unit and installs no new plumbing, so whether you need a permit to finish the space depends on the plan for it, not on the underpinning.

Underpinning step by step, and how long it takes

Toronto underpinning firms describe the same order, and one notes that the City inspects each stage before the next section is opened.

1. Assess the house. A site visit, soil tests where needed and a check of the foundation and plans.
2. Draw and stamp the plans. The engineer sets the depth and the sequence of sections.
3. Get the permit. Nothing is dug until it is issued.
4. Shore and set up. Temporary supports for the floor above, plus a conveyor and bins for the soil.
5. Dig and pour in sections. Each numbered section is excavated and poured before its neighbours are opened.
6. Replace posts and beams. Load posts and beams are replaced or added for the new floor level.
7. Drain and waterproof. Drains, membrane, sump pump and backwater valve go in while the floor is open, and Toronto requires a permit to install a backwater valve.
8. Pour the new slab. The floor goes down over a gravel bed about 4 to 5 inches deep.
9. Close the permit. The final inspection passes, and finishing can start.

A Toronto firm's 2026 figure for the digging and the new floor is 6 to 10 weeks from construction start to the final pour, before any finishing, and another firm's 2025 estimate gives the same 6 to 10 weeks, with 4 to 6 for bench footing. Structure comes first in the order of any renovation, so framing, wiring and drywall wait for the new slab.

When comparing the quotes, line them up on the depth gained, the linear footage and the drainage list before comparing the totals.