Basement underpinning is a method of lowering the basement floor that increases the structural strength of a foundation.
In short, your basement floor is excavated, and your walls are reinforced with a new layer of concrete. It’s an extremely oversimplified explanation, but that’s essentially how basement underpinning works, technology-wise.
There are several different types of materials used, including reinforced concrete, steel and sometimes — timber constructions. Depending on each individual case, some installations may also include waterproofing measures to prevent water from entering the foundation walls.
Concrete: Concrete is one of the most commonly used materials for basement underpinning. It’s durable enough and easily adjustable at the same time.
Steel: Another alternative approach is steel underpinning. Steel beams are welded to the existing foundation walls and are then filled with concrete giving the steel greater strength. You won’t see this method often in residential areas in Canada, but it’s still one of the most cost-effective options when pure concrete is not enough.
Timber: Basement underpinning can also be done using timber units. It’s less commonly used because it tends to cost more than other methods and is significantly less reliable.