Should I Worry About Cracks In My Foundation Floor?

Crack in foundation floor in Toronto homeDo you have cracks in your foundation floor?

Cracks are a common feature in most homes. There are many things that can cause cracks to appear, from poor initial workmanship, to a shifting of the foundation itself.  Cracks can be harmless or can mean serious trouble, what you need to find out is what’s causing the cracks in the first place.

The good news is that foundation floors are seldom structural. That’s because they are concrete poured in between foundation work. There are two reasons why cracks may develop in this. These are:

  • The earth beneath them was inadequately compacted before the concrete pour, and gave a little under the extra weight.


  • The concrete cracked because that is what large concrete areas generally do as they dry out. Some builders keep concrete flooring moist for longer periods of time to avoid this.

Hence your cracked concrete basement floor is not something you need to fret about for safety’s sake. Or is it perhaps? Read on and discover things you may not know.

Gas Intrusion

Undetectable methane and radon gas accumulates in pockets underground which are seldom tested during surveys.  Sometimes a builder may disturb one and cause the gases to gradually escape. While the foundation work is supposed to keep them harmless a cracked basement floor manifestly cannot. Methane gas is violently explosive. Radon gas is the most potent cause of lung cancer after cigarettes.

Insect Infestation

Concrete floor cracks are perfect breeding places for ant and termites, from where they can fan out everywhere in your home. Tackling them upstairs is hardly the right place to start when they’re reproducing themselves constantly in the floor below. In extreme cases wide cracks can even harbor snakes. Thankfully, this is uncommon, especially here in Toronto.

Damp and Mold

There’s always moisture underground. That’s where rainwater naturally ends up, and after that can go almost anywhere. The force of gravity pressing down on the earth above makes ground water surprisingly intrusive. If you ignore non-structural floor cracks, don’t be surprised to find water bubbling up through them after heavy rain.  If your home sits on a high water table, cracks can be an open invitation for a wet basement.

This problem is especially serious in basements underground. That’s because we seldom go down there to inspect. Damp conditions below the earth’s surface are perfect conditions for moss and mold to grow. Especially if the room’s kept tightly closed, and there’s no exchange of fresh air.

Fixing Foundation Floor Cracks

Like most things in life, there’s a right way and a wrong way to seal floor foundation cracks. The wrong way is to conceal the problem with surface filler. The better way is to pour in a polymer compound that forms a bond with both concrete sections. Best of all for wider cracks is to use an epoxy filler to recreate the original monolithic pour. However the stuff is expensive and you may need a concrete flooring specialist with experience and the right injection tools.

If you have any questions about foundation problems in your home and live in the Greater Toronto Area, feel free to contact us for a free consultation.

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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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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.