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Causes of Concrete Cracks & Sinking

Cracked and sinking concrete surfaces can be a real pain to deal with, perhaps because there are so many potential causes.


Concrete is one of the most versatile and accessible construction materials in use today; it can be shaped, poured, and made into almost anything that you could want. Concrete does have a few weaknesses, however. For example, despite being very strong and durable, it can also be brittle and susceptible to water damage. So, when you notice cracks spreading, slabs sinking, or pitted, flaked, and stained sections of concrete in your home, you may start to worry as there could be so many potential causes. Thankfully, there are many different solutions. With the right tools, materials, and knowledge, the experienced team at Innovative Basement Authority could make concrete damage a thing of the past. 

sinking concrete

What Causes Concrete Damage and Sinking

Damage to concrete structures in, under, or around your home can come from many sources. The causes of damage either begin in the soil under your home and other structures on your property, or in the climate itself. 

  • Soil-Based Problems  

The soil underneath a property is just as important as the strength of its foundation. It could be argued that it is more important. After all, your foundation rests on this soil and relies on its stability just as the structure of your property relies on its foundation. 

Soil-based problems come in the forms of instability and erosion. Poorly compacted soil is a fairly common problem that starts when a property is being constructed. The movement of soil around the site during construction disturbs it. Though construction companies take the time to replace and compact the soil, it is never as stable as it was before excavation. If soil is poorly compacted, it can begin to shift and settle, leaving voids between your home and the ground. 

Erosion is often connected to poorly compacted soil and climate-based factors and issues. Heavy rainfall, for example, can wash away exposed soil that is poorly compacted and has nothing to hold it in place. As the soil washes or blows away in periods of intense dehydration, it leaves concrete structures under-supported. This can lead to settlement, cracking, and sinking. 

  • Climate-Based Issues  

Climate-based issues can affect your property either from below, through the soil, or from above by direct contact with concrete structures. The main climate factors that affect soil are excess moisture, extreme dehydration, and frost heave. 

If the climate you live in is very wet or humid, the amount of water in the soil can vary drastically. Rainfall can increase saturation levels, but there are also some areas that simply have very marshy soil. Incredibly wet, loose soil can lead to subsidence in all kinds of structures. This process of sinking can cause cracking and further sinking. Excessive dehydration, by contrast, shrinks and cracks. When it does this, it leaves large gaps which your foundation can fall, or settle, into. 

Frost heave is what happens when the moisture in the soil freezes and expands quickly. This can cause a hump or bulge in your basement or flooring. If subsequent dehydration causes the soil to shrink, however, this bulge can collapse and become a depression. 

Troubleshooting: Why Is the Concrete Around My Home Cracking?  

There are many potential reasons why poured concrete surfaces in your home are cracking, buckling, flaking, or becoming pitted and brittle. At the very root of it all, however, damaged concrete tends to come down to problems in the soil under your home, or in the climate. Too much pressure, too little support, or too much moisture can cause many problems. Recognizing the causes of such damage around your home can be tricky.  

Cracking and Crumbling 

In the case of cracking and crumbling concrete slabs and surfaces around a home the most likely causes are excessive pressure or the presence of flaws. Telling which is truly to blame is a matter of context.  

If the cracking in a concrete surface is localized to areas of bulging, for example, pressure is most likely to be the cause. By contrast, widespread and intense fragmentation which is accompanied by cosmetic issues like spalling is most likely to be caused by fundamental flaws in the concrete itself.  

Movement and Sinking 

When you see concrete surfaces around your home moving laterally or sinking into the ground, the most likely underlying factors are weakness in the soil, oversaturation, or processes like soil washout and erosion.  

Lateral movement is most likely to be connected to excessive soil saturation and bad weather, while sinking is more likely to be connected to processes which lead to soil displacement. One further possibility is the presence of too much weight on the impacted surface.  

Signs of Damage and Sinking 

While bulges, tilting, and depressions are sure signs of damage to concrete floors, walls, or your property foundation there are other more subtle signs that you can look out for. Learning to recognize these signs will help you to catch damage before it snowballs into a huge, structural problem. Smaller signs of damage or the onset of sinking or settlement in your property’s concrete surfaces within your home. These are: 

  • Gaps 

When gaps form under the edges of concrete slabs and surfaces around your home, you can be certain that they are in danger of becoming damaged in some way. This is a sign of advanced soil displacement, either via erosion or soil washout, and should not be ignored.  

  • Visible Soil Displacement  

Another problem sign for the concrete surfaces around your property is the presence of visibly displaced soil around your property after periods of intense rainfall or high winds. If you see this before the concrete around your property becomes damaged, however, you may be able to avoid damage by acting quickly.  

  • Unevenness and Movement 

Unevenness, sinking, and other forms of movement are all strong problem signs when it comes to the concrete surfaces and slabs around your property as a whole. Sinking, heaving, and lateral movement are all forms of damage in and of themselves, but can also lead to cracking, spalling, pitting, flaking, and crumbling.  

  • Spreading Cracks 

Cracks in concrete are fairly common and can come about as a house settles. If the cracks are static and do not seem to be letting in water, you can relax a little. If, however, the cracks are spreading this is a sign that the structures in question are under continuing strain and may need to be repaired or bolstered. 

Repairing Sinking or Cracked Concrete 

The possible solutions for cracked, sinking, or bulging/bowed concrete are numerous and the best possible repair methods are decided by the underlying causes. Cracks and depressions caused by a damaged foundation, for example, require different solutions than those caused by excessive hydrostatic pressure in the soil around your home. Innovative Basement Authority provides several specialist solutions, including: 

  •  Concrete Lifting with PolyRenewal™ 

Concrete lifting can be undertaken in several ways, but we favor the PolyRenewal™ method because it is lighter, more durable, and more efficient than mudjacking or replacing damaged concrete surfaces. This polyurethane foam is waterproof, durable, and can be tailored to suit almost any situation, and yields high-quality, long-lasting results. 

PolyRenewal™ is a uniquely effective concrete repair method which is capable of lifting, stabilizing, and repairing sunken, damaged, or cracked concrete surfaces and slabs without excessive excavation or disruption. This is done by drilling holes in the damaged concrete, installing injection ports, and injecting the pre-mixed foam into the cavity below a damaged surface where it will expand. 

Contact Innovative Basement Authority for Help with Your Concrete 

Whatever lies at the bottom of your damaged, sinking, or cracked concrete, Innovative Basement Authority is here to help. Our team is expert in finding the best possible solution for even the most complex of cases. All of our inspection appointments are free and come with no obligation to book repairs through us. We ensure that all our staff takes a friendly, customer-led approach when conducting inspections; you will face no pressure sales tactics, and we will provide you with a written estimate on the day of inspection. This will ensure that you have all the information that you need to make the best decision for your property. 

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We service Minnesota, North Dakota, South Dakota and Eastern Montana for basement waterproofing and crawl space repair.

Fargo, ND

1330 41st St. N
Fargo, ND 58102

Minneapolis, MN

6265 Carmen Ave.
Inver Grove Heights, MN 55076

Rush City, MN

1325 S Frandsen Ave
Rush City, MN 55069

Sioux Falls, SD

101 S. Reid Street, Suite 307
Sioux Falls, SD 57103