Vertical Crack In My Foundation Wall

Vertical Foundation Wall Cracks

A foundation is the structure on which a home or other building rests. It may be a simple trench filled with concrete on which the brick walls stand. It could also be a concrete-reinforced sheet under the entire building. Where the ground slopes, there may be foundation walls as well, to make up the height difference.

Where a basement is constructed beneath a dwelling, these foundation walls go up to full room height, and receive immense pressure from the weight above them. Unfortunately not all builders make good engineers. If the forces bearing down on foundation walls are incorrectly calculated – or they are inadequately supported by their footings – then the walls will inevitably crack.  Cracks in the foundation can also be a result of shifting of the earth around the foundation, causing enough movement and stress for it to crack.

Toronto home with vertical crack in foundation

Warning Signs

Vertical foundation cracks usually develop during the first few years after construction finishes, as the building settles and the concrete finally cures. They typically start as hairline cracks that progressively open up. A structural engineer is able to measure their movement, and to determine whether the cracks are new developments, or older history.

It is also possible for basement wall cracks to develop when peripheral events affect an existing structure. These could include alterations to the property, blasting in the neighborhood, or even an earth tremor. It’s important to monitor for basement cracking during events like these, so that an insurance or other claim may be lodged before the opportunity expires.

Consequential Problems

Most times a mildly cracked foundation wall is more of an irritation, because it admits moisture and even drops of water through it. Nonetheless, homeowners are strongly advised to consult an a qualified contractor or engineer if in any doubt. The more serious consequence is often a reduction in the value of their home, since buyers often run a mile from the sight of cracks.

“Solutions” That Don’t Always Work

The only sure-fire way to seal a leak is at its source (unless it’s a hairline crack that may be filled with polyurethane). As a professional foundation contractor in Toronto, we get hundreds of calls a year for foundation cracks, including following up on poor attempts to fix them.  The following are examples of botched jobs we often come across:

  • Amateurish attempts like papering over basement wall cracks or filling them with commercial caulking seal. These are inevitably bound to fail as efflorescence builds up behind the sealant causing it to peel away. It’s also almost impossible to obtain a dirt-free, perfectly dry surface with which to bond.


  • Commercial filling with hydraulic cement or other rigid substances is also bound to fail, because the structure will still shift with seasons, while the hydrostatic pressure from outside continues unabated. The same applies to epoxy seals to a lesser extent. They may sometimes work for years though – provided they are attached to a perfectly clean dry surface

Flexible, expandable urethane sealants may work where a crack has stabilised. However their elasticity is limited, while cracks can expand by up to 100% quite quickly. For this reason they are not ideal.

The Real Solution

Where vertical foundation wall cracks are serious, or there’s water pouring through them in the rainy season, the only viable solution is to remove the outside soil, to install a french drain or other soak-away system, and to apply a flexible waterproofing sealant or membrane from the outside.

Repairing and/or waterproofing a foundation  can be expensive for the homeowner, it’s also alot of work. If you’re going to do it, be sure it’s being done by a professional that will offer a guarantee on their work and has experience working with foundations.



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NuSite Group is a Toronto based basement waterproofing and foundation repair company that specializes in Basement Waterproofing, Basement Lowering, and Foundation Repairs. Call us today at 416-622-7000 or 905-731-1228 for a free in-home estimate and inspection.

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Customer Testimonials

Interested in working with us? Check out some of our customer testimonials below and find more on Homestars. We are one of the highest rated basement waterproofing companies in Toronto

Mark Lipton - Homestars Review

Basement Waterproofing

Our basement leaked! Of course . . . we bought a 100 year old house! But my office needed to be in the basement permanently. I interviewed 10 different companies until we decided on the Steinbergs and their crew at Nu-Site! They are professional, reliable, courteous, honest, and they really make an effort to communicate with the client about every step of the process.

Sara Jack - Homestars Review

Foundation and Waterproofing Repairs

After several years of chronic leaks, we decided to have our basement waterproofed once and for all. The team over at Nusite was professional, answered my questions during the project and stayed within their quoted price....which is always a concern for me when working with contractors. Great job overall

Joshua Persaud - Yellowpages Review

Basement Waterproofing

Had several cracks in my basement wall and they would leak whenever we had a heavy rain. It started about a year and a half ago and seems to have gotten worse over the past 6 months. I tried having my neighbor seal it, but it started leaking again within a few weeks. Called several waterproofing companies and got several quotes. Finally went with Nusite contractors for the job. They gave a reasonable quote and I liked the guy that came by for the estimate. They stayed within budget and cleaned up before they left. It's been almost 3 months now and it seems to be working great.