The word “underpinning” technically means laying a foundation to support or strengthen a building, but it’s regularly referred to in the construction business with a slightly different meaning. When experts talk about underpinning they’re specifically referring to strengthening the support underneath a building or increasing the square footage of that support. No matter the job, the cost of underpinning is not simple to arrive at.
First of all, never approach the idea of underpinning a structure as a DIY project. This is a serious undertaking that requires trained professionals to do right. Luckily, finding out the cost of underpinning in Canada is not too difficult as many companies that provide this service are usually willing to provide free quotes.
However, even before making the decision to get underpinning, many people want to know the ballpark range or average cost for such a project. There are two major reasons as to why people look into getting underpinning done:
Subsidence – This is a scary thing to have to happen to one’s house or one’s business, but there’s no reason to panic in most cases. Yes, the work needs to be done, but it’s only in extreme cases that the building is structurally unsafe. Subsidence is noticed by cracks in the plaster or walls of a building.
Expansion – This is the voluntary end of underpinning and happens when people are adding another floor to an existing building or they’re expanding outward from the current building. In either case, the underlying support for the structures needs to be strengthened.
In either case, the average cost of underpinning a home or business is about the same. What can definitely affect the price is when a basement ceiling height is being raised to make the basement a habitable space. In these cases, the floor needs to be excavated and the cost to do underpinning goes up, considerably.
What affects the price of underpinning the most is what type of underpinning is being done. There are three different kinds of underpinning that can be done, depending on what someone wants to do with their home or business:
The Beam Method – This approach involves digging out a hole at regular intervals underneath the wall, or walls that require underpinning. Those holes are dug on undisturbed earth, which is then filled with concrete. Supporting beams are then placed on those surfaces, forming strong support, or underpinning for load-bearing walls of the building.
Mass Pour – This is the Beam Method, but with existing concrete. What happens is that the existing floor has holes dug beneath it. These are also filled with concrete to obtain the same increase in support. This sounds like a big job, but it can usually be done without the need for heavy equipment.
Piling – This approach is one that most homes will never use. Piling involves deep support for much larger structures, such as high-rises and skyscrapers. This requires building deep foundations of up to 5 meters, or roughly, sixteen and a half feet. Most people don’t have to think about this option and it is also, by far, the most expensive.
So, what does this all mean? What is the average cost to do underpinning in Canada? Isn’t there a simple answer? Well, no! Because of these different types of underpinning and the different reasons as to why people have it done, costs can change.
The short answer, however, is that for a simple underpinning that doesn’t require any major excavation of the basement, the average cost is about eighty dollars per square foot in a major city. For more complex jobs, the cost goes up to about four hundred and fifty dollars per square foot.
There are other considerations, however, that will affect the overall cost to have underpinning is done that goes beyond the actual cost of the underpinning, itself. In Canada, the homeowner or business owner also has to obtain a permit and proper blueprints have to be drawn for the work. The average cost of this in most major metropolitan areas where permits are required is a total of about twenty-five hundred dollars on the high end.
With all of these considerations taken into account, the cost of underpinning a one-story two thousand square foot home would be about one hundred and sixty-three thousand dollars on the low end and as much as over nine hundred thousand on the high end!
Most homes with a thousand square feet to underpin would have an average cost of at least eighty-three thousand dollars and as much as just over four hundred and fifty thousand dollars.
These are, of course, average costs in major cities. The price can vary a great deal from city to city, and more rural areas usually have lower costs associated with them. As always, the best thing to do is to call up a construction company and get a free quote!