Underpinning vs Benching in Toronto: Costs, Space and Choosing the Right Option

What are underpinning, benching and bench footing?

Your foundation walls sit on footings. Digging the basement floor below the underside of those footings would remove the soil holding them up, which is why lowering a floor almost always needs either underpinning or benching (K.H. Davis Engineering (opens in a new tab)).

Underpinning increases the depth of the existing foundation by constructing new footings beneath the existing ones (City of Toronto (opens in a new tab)). The work is done in short sections, in stages, because the wall is still carrying the house while it happens.

Benching lowers the floor without extending the footings. A slope of undisturbed soil is left in front of each footing and covered with a concrete bench, reinforced and tied into the new floor so the footings cannot slide inward (K.H. Davis Engineering (opens in a new tab)). The bench stays in the finished basement as a ledge along the walls.

Bench footing is used inconsistently. Most Toronto contractors use it as another name for benching; some use it for a new footing poured beside, rather than under, the existing wall. No City guidance defines it, so ask the contractor to show exactly what they mean on the drawings.

Underpinning vs benching cost: what changes the price?

Contractors generally publish lower rates for benching than for underpinning, though an engineered bench can cost as much. The two Toronto-area contractors below each price both methods per linear foot. These published rates show how each contractor prices the methods. Compare the stated depth and included work before using them to plan your budget.

Each contractor’s own published rates, not a Toronto market average or a quote. Do not add the separately listed items together: they overlap differently in each quote.

The same company can also price different kinds of bench differently: Strong Basements lists an engineered bench at a higher starting rate than a regular bench. And some quotes split the work between trades. OCM Excavation (opens in a new tab) (May 25, 2026) prices the excavation portion and leaves concrete forming and pouring to a separate crew, so its per-foot rate describes less work than a structural quote.

What moves the total most:

• Length of wall. Both contractors price per linear foot, so the length of foundation wall being lowered drives the structural cost.
• Depth. A deeper lowering means more excavation, and with benching a wider bench.
• What sits outside the structural price. A new slab, drainage and waterproofing, interior posts and beams, stairs, plumbing changes and finishing are often separate lines.
• Engineering and permits. The City’s permit fee for underpinning is $12.37 per linear metre, with a $214.79 minimum (2026 fee schedule (opens in a new tab)). Engineering design and field reviews are priced by the engineer or included by the contractor.

Kildrin’s Toronto underpinning permit data shows historical construction values applicants declared at filing for permits that mention underpinning or basement lowering. The category does not separate methods, so it cannot show what benching costs or how much it saves.

How does each option affect usable basement space?

Underpinning keeps nearly the full floor area. Benching gives up a band along every benched wall, and the band widens with depth because the soil slope under the bench has to stay stable. In one Toronto structural engineer’s example, lowering a floor by 6 inches needed a bench about 12 inches wide, and lowering it by 18 inches needed about 27 inches (K.H. Davis (opens in a new tab)). Your bench depends on your soil and design, so use the drawings, not a rule of thumb.

Where the difference shows up:

• Furniture and storage. Beds, sofas, desks and cabinets usually go against walls. A bench pushes them into the room or needs built-ins designed around it.
• Stairs and circulation. Lowering the floor means extending the stairs. An underpinned or benched wall base can interfere with a stair beside it; the engineer’s options include a landing or a short section of underpinning flush with the wall (K.H. Davis (opens in a new tab)).
• Bathrooms and bedrooms. Toilets, vanities, showers, closets and beds all need wall space. Check that each fits in the room that remains beside the bench.
• Planned use. Storage or a mechanical room can live with a bench. It is common to leave the furnace and water heater in place and bench around that room while other areas are treated differently (K.H. Davis (opens in a new tab)).

Headroom matters as much as floor area. The new floor needs a gravel layer and concrete on top, and ceiling finishes and bulkheads take height back (K.H. Davis (opens in a new tab)). Ask each contractor for a plan and section showing the finished clear floor dimensions between walls or bench faces, the finished ceiling height and the stair layout. Toronto underpinning permit drawings already have to show floor-to-ceiling heights and the depth of underpinning (City guide (opens in a new tab)), so this is a reasonable request.

Which option fits your Toronto basement?

A qualified professional decides this after looking at your house. These are the conditions they assess, and why each matters:

• Existing foundation. The depth, width and condition of the current footings and walls set how much lowering either method can achieve.
• Soil. The City requires professional design and field review when the soil is clay or silt, or when underpinning exceeds 1,200 mm of laterally unsupported height (City guide (opens in a new tab)). The engineer K.H. Davis advises caution with benching in loose granular or soft wet clay soils, and engineer direction once the wall retains more than about 5 feet of soil.
• Groundwater and sewer depth. Lowering the floor can put it below the water table, and a shallow sewer drain may mean pumping wastewater up. An engineer may recommend test pits before work starts (K.H. Davis (opens in a new tab)).
• Neighbouring foundations. If the new foundation goes below an adjacent building’s footing within the soil’s angle of repose, a Professional Engineer must design and review it on site (City guide (opens in a new tab)). Benching is sometimes chosen to avoid undermining a close neighbour, and with less than about 48 inches between houses the method needs careful thought (K.H. Davis (opens in a new tab)). Semi-detached houses share a wall, so this applies directly.
• Depth and layout. The deeper you go, the wider a bench becomes. If the bench would take the space you are lowering the floor to gain, benching may not suit.

Questions to ask the engineer or contractor:

• Which method do you recommend for each wall, and why?
• How will you check the soil, groundwater and sewer depth before pricing?
• How close is the neighbouring foundation, and how deep is its footing?
• What finished ceiling height and floor dimensions will I get?

More ceiling height is not the same as a legal apartment. A second unit needs its own building permit and must meet the Building Code for dwelling units (Ontario (opens in a new tab), City secondary suites guide (opens in a new tab)). If a rental suite is the goal, design for it before choosing a lowering method, and see the basement apartment conversion permit data as a separate sample.

What permits and drawings should you check in Toronto?

• A permit is required. Toronto lists basement underpinning, and excavating or constructing foundations, as basement work that needs a building permit (City (opens in a new tab)). The list does not name benching. Some contractors say benching needs fewer or no permits; no City source says so, so confirm with Toronto Building before relying on it.
• Engineering is part of every underpinning job. Even when a Professional Engineer is not required to design it, the City requires engineer testing and reports during the first and last stages of construction to pass inspections (City guide (opens in a new tab)).
• The drawings show the plan. The foundation plan must show the numbered stages and the linear metres of underpinning, and, where applicable, the distance to and footing depth of adjacent buildings (City guide (opens in a new tab)).
• Review time. Underpinning on a house with no more than two units can qualify for the City’s Express Services, where an examiner reviews the application within 3 days (City (opens in a new tab)). That covers review, not design or construction.

What should both contractor quotations include?

Two prices only compare if they describe the same basement. Ask both contractors to state, in writing:

• The method for each wall, including any mixed sections (for example, benching around the furnace room).
• The lowering depth, the finished ceiling height and the finished clear floor dimensions, on drawings.
• The linear footage priced, and the per-foot rate if quoted that way.
• Who provides engineering design, the required field reviews and testing, and who applies for the permit and pays the fee.
• Excavation, soil removal and access: how soil leaves the site and what that costs.
• The new slab and gravel base, and any interior posts and beams that need new footings.
• Drainage and waterproofing: weeping tile, sump pump and backwater valve, and whether they are included.
• Stair extension, plumbing and sewer changes, and whether any finishing is included.
• HST, and proof that the contractor’s insurance covers underpinning, which many policies exclude (K.H. Davis (opens in a new tab)).

A benching quote that leaves out drainage, or an underpinning quote that excludes the new slab, can look cheaper without being cheaper. If a backwater valve or sump pump is part of the work, the City’s Basement Flooding Protection Subsidy (opens in a new tab) covers up to 80 per cent of the invoiced cost of eligible work, to a maximum of $1,600 per backwater valve and $2,250 for a sump pump, subject to its conditions (page modified June 18, 2026). For deposits, allowances and change orders, use the quote comparison guide.

Other common questions

Can one basement use both methods?

Yes. A short section of underpinning can be used where a bench would block the stairs, and benching around a furnace room is common (K.H. Davis (opens in a new tab)). Ask for each wall’s method on the drawings.

Will lowering the floor fix a damp basement?

Not by itself. A lower floor can sit closer to, or below, the water table (K.H. Davis (opens in a new tab)), so drainage and waterproofing need their own line in the quote whichever method you choose.