As a contracting group specializing in basement underpinning in Toronto, 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.

Digging out a Toronto home for underpinning

.What’s That Got to Do with Basements?

Contractors usually become involved with underpinning basement walls because a home owner 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?”

Stages in the Process

If there was a single basement job not recommended for amateurs or the uninsured), then basement underpinning has to be the one. Get it right, and you’ll add significant value to your home. Get it wrong though, and you could end up damaging the fabric of your house.

Appoint a licensed structural engineer with a record of completed jobs, to prepare statutory documents and obtain approval for the job.

Appoint a basement-underpinning contractor who’s similarly experienced to complete the following work:

Toronto home underpinning


  • Remove a small section of the existing foundation to obtain access underground, and replace it with a load-bearing joist.


  • Excavate alternate strips to the required depth, and pour shuttered reinforced concrete beneath the exposed sections of foundation.


  • When the new foundations are completely cured, complete the balance of the basement underpinning.


  • Lay a new floor when everything is stable, and build out the interior of the extended space.

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.

However, you are effectively building your house “upside down” by adding the walls and floor when the roof’s up already. While the job’s in process the structural integrity of the entire building is compromised in the short-run. If it fails, then your new basement could end up costing you a whole lot more than it’s worth.

adding a finished basement in toronto

Insure Yourself

Of course, you should take out extra insurance while the work’s in progress. But no insurer will compensate you for loss caused by an incompetent builder you chose yourself. It’s highly recommended to find an experienced basement under-pinner who is licensed (and insured themselves).


When your about to take on a costly home renovation project, the most important consideration you should make should be the enjoyment and value you’ll receive as a homeowner from this renovation.  If you think you’ll eventually be selling your home in the future, you may want to also consider the increased value this renovation will bring to your home.

Some expensive additions, such as an inground swimming pool, can be very expensive, but could add little value to the asking price for your home in the future. This is dependent on region and locale, here in Toronto, it wouldn’t add much value due to the colder climate and short swimming window….but in a hot climate, an inground pool is a must.

Everyone loves a finished basement or a new kitchen, but not everyone wants a giant swimming pool taking up half their backyard. If you’re wondering which types of renovation add the most re-sale value for you home, check out this infographic courtesy of  While personal enjoyment should be your main concern when investing in a home renovation, it’s also comforting knowing that you’l get most of your investment back if you decide to sell your home one day.

Home renovations that increase the resale value of your home-infographic

These days more and more Canadians are avoiding the cost of unnecessary moves, and upgrading their homes instead. Adding an extra bedroom is a popular project because bedrooms are key factors in property valuations. However it’s important to comply with a number of factors in order to fully reap the benefits of the expense.

The basement is an obvious place to locate a new bedroom. That’s because the walls, floor and ceiling are already there, and that’s a huge cost saving already. Building standards for bedrooms are more demanding than those in basements. This means you’re going to have to consider all the following factors carefully.

toronto finished basement

Caring for Your Health

  • Continuous dampness causes mould that’s bad for you, and can encourage incessant colds and flu. If the water’s actually pooling then your basement project may not even reach the starting blocks. However very minor moisture penetration problems are often cured by applying the appropriate water-lock, after clearing out and correctly sealing cracks.  If you have persistent water problems, you should call in a licensed waterproofing company to fix the problem or else the problems will just resurface again.


  • Aesthetics are important too. We’re warm blooded creatures, and a lack of sunshine makes us feel generally low. Is your basement best described as cold, remote and isolated? It could be better to move the after-hours games room down there instead, and turn the existing one into an extra bedroom.


  • Temperature control is vital. Basements are generally-speaking, cool places that warm up when the central heating furnace comes on. While this may seem an ideal arrangement, the actual temperatures may not be suitable for living space. Speak to an expert. Resolve any concerns before you call the decorators in.
adding a finished basement in toronto

Safety Matters

  • Make sure your electricity supply is installed by a registered electrician who is able to provide you with a compliance certificate afterwards. This is especially critical where there’s any chance of damp returning. While you’re at it, provide an adequate supply of power points. Extra ones don’t cost that much individually, and you never know what lies ahead.


  • Canadian building codes require that every bedroom have at least two exit points. This is especially relevant with a basement-upgrade project. If your home’s on fire how on earth are you going to escape up the stairs? Don’t take the easy way out by pretending you’re creating a workshop, rumble room or sewing room. You need an outside door (or window) that’s equipped for emergency escape.

Be Legal-Wise

  • Don’t take short cuts on these all-important health and safety considerations. The health and welfare of a family member living in your converted basement matters a whole lot more than the money you could otherwise save. Consider the home-insurance implications too, just in case there’s a problem later and the inspector picks the discrepancy up.


  • Go through the due process of local government authority approval before you begin making any alterations. Make sure your contractor understands that you want everything legal too and they have the required permits and certifications to get the job done. Be present every time the inspector calls. Listen and respond to what they say as they have the ability to shut down your project if your not up to code.

Long Term Benefits

When you put a bedroom in your basement correctly and legally, you achieve a lasting benefit that adds genuine value to your property. An illegal or botched alteration can have the exactly opposite effect. You could even end up devaluing your home, especially when a buyer asks to see the approved plans.