As a contracting group specializing in basement underpinning in Ottawa, we often get asked this simple question, “what is underpinning?” Below is a brief answer to that question.

“Underpinning” is an industry term that’s generally used to describe reinforcing an existing foundation. This may be to shore-up a structure that was poorly built originally or has degraded over time, is subject to subsidence or land-slippage, or is being prepared to carry extra weight.  Underpinning is also performed when a homeowner wants to have their basement foundation dug out to increase the ceiling height of their basement.  This is also known as basement lowering.

What’s That Got to Do with Basements?

Contractors usually become involved with underpinning basement walls because a homeowner decides to deepen them to create a full height basement. In this instance, they are sometimes originally little more than crawlspace below a floor. At other times, the plan may be to deepen a basement built for storage, so as to create living space with livable head-height.

Simply excavating out the floor could upset the balance of the foundations, as they slide inwards and crack the walls above. That’s why it’s necessary to dig under them to create a new foundation. Basement underpinning solves the problem of “which comes first, the chicken or the egg?”

Cost-Benefit Analysis

Houses are valued in terms of living space. A new basement could, therefore, increase the value of your home by up to 10% – and you get more living space too. Basements are especially popular when it comes to extending homes, because they retain existing footprints, and seldom affect the neighbors.

Foundation underpinning

Foundation underpinning process

Foundation underpinning digging