Why Is My Concrete Failing? The Top 5 Most Common Reasons
Whether by cracking, sinking, or flaking, it's very typical for concrete to fail. Concrete is the most common material used for driveways and sidewalks around the world. It's known for its durability and longevity. So, this begs the question- If concrete is so strong and long-lasting, why does it fail? Before we get into the "why", let's take a look at how concrete failure might appear.
How to identify concrete failure
Concrete failure can show up in a variety of ways. Let’s get into some of the most common signs of concrete failure.
A common sign of concrete failure is cracks. A few small hairline cracks that aren’t actively growing and spreading are not necessarily a big problem. But larger, growing cracks are an issue that can affect your home's water drainage, affect the aesthetics, and damage your concrete's structural integrity.
2. Water pooling
If you notice that water is collecting and pooling in areas following heavy rain, you may also see concrete failure. The soil around your home should be able to deal with moisture and drain large amounts of water at a reasonable pace, but if water is pooling you might have a serious problem with your soil.
3. Pitting, flaking, staining
Pitting, flaking, and staining are also signs of damaged concrete. Concrete is very porous, so any spills of oil, grease, or other substances can penetrate the concrete, leading to unsightly stains. In addition, the freeze-thaw cycle can be very hard on your concrete. Water can seep into the concrete and expand during freezing temperatures. This repeated expansion and contraction can cause the surface to crack and flake.
And if your concrete isn't sealed, water intrusion and harsh chemicals can wear down the surface and cause it to pit.
4. Uneven surfaces and sinking
A serious sign that your concrete slabs are being undermined is unevenness and sinking. A fully intact slab that is moving is most likely struggling with external factors that need to be addressed.
Why does concrete fail?
Weather, water, and earth. These natural elements have a big say in if your concrete will fail. Hot and cold weather can be harsh on your concrete, creating pressure and cracks. Water can be pesky, going where it shouldn’t. And the soil it is sitting on can be damaging from the start.
On top of issues that weather creates, man-made mistakes can also cause concrete failure. Below are the top 5 reasons concrete can fail.
1. Poorly compacted soil
When your home was built, a lot of soil was moved around and then put back. This caused loose, poorly compacted soil to surround your home. Even if the replaced soil was compacted well, it will never be as stable as the original, untouched soil.
When you have loose soil around structures, like a driveway or even your home, water seeps in. And that water saturates the soil and then that soil eventually dries out. This constant expansion and contraction can create voids beneath your concrete slabs that they then sink into.
The weather has a huge impact on the condition of your concrete. These are a few different issues concrete can face due to weather and why it happens.
- Flooding: When it's dry for a long time, cracks and crevices form in the soil surrounding your concrete. And when it rains after a dry period, the water has an easy pathway to enter beneath your concrete. As a result, this wet, soft soil is just too weak to support the concrete above it. In the worst case, the soil erodes and washes away completely, leaving behind large voids that cannot support the weight of the concrete above.
- Hot weather expansion cracks: During hot weather, concrete heats up and expands. This is like running a tight metal lid under hot water to expand the lid and help you open the jar. The metal lid has all the room it needs to expand, but when concrete expands, it usually doesn't have much room to budge. This will cause pressure throughout the concrete slab, and cause cracks to appear.
- Cold weather heaving cracks: During cold weather months, the moisture in the ground under the slab will freeze, and the slab itself can shrink, causing the concrete to lift and heave. This puts pressure on the concrete and causes it to crack.
3. Excessive weight
Concrete is very strong, but it's not indestructible. Anything excessively heavy on top of the concrete can cause cracking. In residential areas, this usually isn't a major concern. But if you live in a colder climate, heavy snow can be a problem. The softened ground, coupled with the added weight on the concrete slab, may cause it to crack under pressure.
Imagine a sponge. When it is filled with water, it gets larger, and over time the water evaporates, dries the sponge out, and shrinks. Concrete behaves similarly. When concrete is being installed, water is used to facilitate mixing and pouring. As the concrete cures, the excess water gradually evaporates, just like that sponge. This evaporation causes the concrete to undergo a reduction in volume, resulting in shrinkage. This process of shrinkage exerts pressure on the concrete, potentially leading to cracking.
5. Concrete defects
Your concrete can crack due to improper installation or a poorly prepared concrete mix. Concrete is made up of three major components: water, aggregate, and cement. Water is the key ingredient to bind the aggregate and cement into a paste. But when the concrete mix is not prepared correctly, it may have the wrong water-to-cement ratio, leading to weak concrete that's more prone to cracking.
If your concrete has the perfect mix but is still damaged, bad installation could be the cause. Proper curing is essential for concrete to gain its full strength and durability. If it is not accurately cured or the curing process is interrupted, it can cause premature drying and shrinkage, leading to cracks.
Why you should worry about failing concrete
Failing concrete may not seem super important, but it can actually lead to a range of safety, structural, and financial issues.
First and foremost, cracked or deteriorating concrete can be a tripping hazard, especially in high traffic areas like driveways or sidewalks. Uneven and unstable surfaces pose a risk to you, your loved ones, and anyone who visits your property and could result in serious injury.
Secondly, failing concrete can significantly impact your property value. Whether it's a cracked driveway or a crumbling patio, damaged concrete can reduce the value and visual appeal of your home.
Lastly, failing concrete is a degenerative issue. Once the issues begin, there is no way that they will reverse and will only get worse. Addressing concrete failure early can help prevent minor issues from turning into major repair projects. Delaying repairs can lead to more extensive damage and a higher repair bill.
What to do if your concrete is already failing
If you're noticing early signs of concrete failure, it's essential to take proactive action and involve a professional as soon as possible. Ignoring these issues won't lead to self-repair; on the contrary, concrete problems tend to worsen over time. By engaging an expert, you can address the problem at its root, prevent further deterioration and ensure a safe and lasting solution.
Here at Thrasher Foundation Repair, we offer multiple services to fix your failing concrete, including concrete lifting, joint and crack caulking, and surface sealing. These services are included in our 3-Part Concrete Protection Systems: PolyLevel, NexusPro, and SealantPro.
PolyLevel is a high-density polyurethane foam that's waterproof, environmentally friendly, and long-lasting. This helps to lift and level concrete by injecting the foam beneath the slab through penny-sized holes. The foam will start to expand and harden, lifting the slab into place while also compressing the surrounding soil. Compared to traditional mudjacking, PolyLevel addresses the stability of the slab, allowing a more permanent solution. After PolyLevel is installed, we use NexusPro.
NexusPro is our UV-resistant silicone-based crack and joint sealer. It applies like caulk, but it works better than the traditional big-box brands. NexusPro won't crack, bubble, or dry out, and can also prevent water from flowing under the slab, creating weaker soil and washout. The best thing about these two products is that they both have a very quick curing process. Within a matter of hours, you can use your concrete as you normally would.
The last product of our Concrete Protection System is SealantPro. This is applied as a topcoat to protect your concrete against the elements and permanently bonds to your concrete. These big 3 also come with a big warranty of 5 years!