A bench footing gets the floor lower without ever going below the existing footing. An angled concrete bench is poured against the inside of the wall, and the floor is dug down in the middle of the room. It is faster and cheaper than underpinning — and it costs you a strip of floor around the entire perimeter, permanently.
Soil under a footing does not carry load straight down in a narrow column. It spreads outward at an angle. As long as you stay outside that spread, you can dig lower next to a footing without taking away the ground that is holding it up.
That is all a bench is: a concrete wedge that keeps the excavation outside the load path, holds back the soil under the footing, and gives the new slab something to stop against. Nothing goes underneath the existing footing, so there is no sequencing, no dry-packing and no curing schedule between rounds. It is a much shorter job.
The bench is permanent, it runs around every wall you lower against, and it is roughly as wide as it is tall. The deeper you go, the further into the room it comes. In a wide rec room that strip is a place to put a sofa back against. In a narrow basement bedroom, it is the difference between a room that works and a room that does not.
It also means the finished wall is not flat to the floor. Framing, baseboard, flooring and any built-in furniture all have to deal with a ledge that is not going anywhere.
The honest test is not budget first. It is whether the perimeter of that basement is space you were going to use.
Yes, and on a lot of houses that is the sensible answer. A wall that a bathroom or a stair is going against can be benched while the walls of a bedroom are underpinned. It has to be drawn that way from the start, because the two details meet at the corners.
It comes out of the drawings, and it is driven by the angle the designer uses and by how far down you are going. As a rule of thumb it is in the same ballpark as the depth you gain, which is why deep lowering and benching are usually a poor pair.
It is structural work on the foundation and on the floor, so yes — drawings and a building permit, the same as underpinning. The cheaper method is not the unpermitted one.
Technically yes, and it is an expensive way to arrive at underpinning. If there is any chance the basement becomes a second unit later, that decision is worth making before the first pour rather than after.
Send the height from your floor to the underside of the joists and a photo of the wall. We will tell you what is possible before anyone quotes anything.