Underpinning vs Benching: Which One Fits Your Basement?

You want more headroom in your basement. There are two ways to get it: underpinning and benching. Both lower the floor. They are not the same job, they don’t cost the same, and they don’t leave you with the same room. This guide explains the difference so you can pick the right one for your house.

The short answer

Underpinning builds new footings under your existing footings, one section at a time, and lowers the whole foundation. You keep the full floor area, wall to wall.

Benching leaves the existing footings where they are. The floor is lowered in the middle of the room, and a concrete ledge, called a bench footing, is poured around the inside of the walls to hold the soil under the old footings in place. You get the height, but you lose floor space along every wall.

Benching usually costs less. Underpinning gives you a better room.

How underpinning works

Underpinning a foundation means digging under the existing footing in short sections and pouring new concrete footings and walls below it. The sections are dug in a set order so the house is always supported. Once every section is done, the old floor comes out and a new basement slab goes in at the new depth.

In Toronto, underpinning needs a building permit. A professional engineer has to design it and review it on site when the new footing goes below your neighbour’s footing and within the soil’s angle of repose, when the unsupported height is over 1.2 metres, or when the soil is clay or silt. In every case, the City wants engineer testing and reports at the start and end of the work. You can read how we handle it on our basement underpinning page.

How benching works

With benching, the crew digs the floor down inside the foundation but stops short of the walls. The soil left under the old footings is held in by a sloped or stepped concrete bench, poured against the inside of the foundation walls. How far the bench sticks into the room depends on how deep you go, the soil and what the engineer specifies.

There is less excavation under the house, fewer sections and less engineering, which is why benching is usually the cheaper option. It still needs a permit and the right design for your soil and depth.

Underpinning vs benching, side by side

	Underpinning	Benching
Floor area	Full room, wall to wall	Smaller: a concrete ledge runs along the walls
Cost	Higher	Lower
Work under the existing footings	Yes, in sections	No
Walkout or separate entrance	Works well	Harder: the bench gets in the way of a new opening
Legal basement apartment	Best option: full height and full floor area	Possible, but the lost floor space can make the layout tight
Finishing	Straight walls, easy to frame and insulate	The bench has to be framed over or left as a ledge

When benching makes sense

• You only need a little more height, and the room is large enough to give up some floor along the walls.
• The basement is for storage, a gym or a rec room, not a separate unit.
• You are working to a tight budget and don’t plan a walkout.

When underpinning is the better choice

• You are building a legal second unit and need every square foot.
• You want a walkout or a separate entrance. See our guide on what a walkout basement is and what it takes.
• The basement is small, and a bench would eat too much of it.
• You want straight, full-height walls that are simple to finish.

Questions homeowners ask

Is underpinning or benching cheaper?

Benching is usually cheaper because there is less digging under the house and fewer sections. The real price for either depends on the length of wall, how deep you go, the soil and access. Send us the address and your current ceiling height and we will price both.

Do I need a permit for benching?

Yes. Lowering a basement floor is structural work, and the City expects a permit and a design that suits your soil and depth.

Can I underpin later if I bench now?

It is possible, but you would be paying for the basement twice. If you think you will want a full-height unit or a walkout later, underpinning now is usually the better use of the money.

What is a bench footing?

It is the concrete ledge poured around the inside of the foundation walls when a basement is benched. It holds the soil under the old footings in place so the walls stay supported.

Not sure which one your basement needs?

Tell us the address and your current ceiling height, or send the engineer’s drawings if you have them. We will tell you whether underpinning or benching fits, and give you a clear, line-by-line price. Get a free quote or call (416) 785-7838.