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Cracked Floor Slabs

Cracked floor slabs are a very serious issue that can indicate problems with your property’s structure. Acting quickly could save you time and money.

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If you have concrete slab flooring in certain parts of your home, then it is likely that they have been covered by wood, vinyl flooring, or even carpets (unless they are in the garage or basement). This means that it can be hard to see signs of cracking and damage unless you are lifting or replacing the flooring over the slabs. As such, it is important to check your concrete floor slabs properly whenever you get the chance to. Even small cracks and shifts in position can be problem signs of real and considerable damage at work around your home. 

For homeowners in Knoxville, TN, cracked floor slabs can seem like a small issue in the grand scheme of things. Taking care of a home can feel like an uphill battle from time to time. Seasonal maintenance work alone can pose a remarkable burden, depending on the size of the home itself. 

Of course, cracks in your concrete flooring can be a very serious problem and should not be ignored.

slab pier
Concrete slab piers being used underneath a floor to help stabilize the floor permanently.

Notice how the piers can extend deep below the floor, extending until they reach competent supporting soils.

Why Worry About Cracked Floor Slabs? 

A few cracks in your concrete floor slabs may not seem like a huge issue, but there are several reasons as to why you should be concerned about cracked floor slabs around your home. Primarily, spreading cracks are a sign of damage and instability no matter what surface you find them in. As such, you should worry about cracked floor slabs because they could be just the beginning; there is no telling what could be going on beneath the surface and out of sight. 

Secondly, if the underlying issues that are causing your floor to crack are structural in nature, then they will only get worse over time, even if the cracks are stable. Structural problems are notorious for developing and spreading in unexpected and worrisome ways. 

Finally, any damage to your flooring or the foundation beneath it poses a significant risk of causing sinking and unevenness. These issues, in turn, cause tripping and falling hazards for you and anyone in your home. In fact, even cracks can present a tripping hazard if they are large enough. As such, you should not consider cracked floor slabs a benign issue. There are dangers associated with failing to fix them. 

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Problem Signs: What Concrete Floor Slabs Can Signify 

Above and beyond all else, cracked floor slabs are problem signs that indicate that there are deeper issues at work in your home. It takes a significant amount of pressure to cause concrete to crack in this way. At its most basic level, this is an issue that is caused by damage to the property’s foundation. There are many different issues that cracked floor slabs can feasibly be a warning sign for, but these are the most common: 

Expansive Soil 

Expansive soils are quite common in and around Knoxville, TN; this is a real problem considering how damaging and destructive they can be. Made up of soils that contain mostly absorbent and water-reactive soils like clay, these kinds of soil swell and shrink depending on how saturated they are. If a property has good moisture management and drainage capabilities, then the changes in volume should be slight, but this is not always the case. 

If extreme weather leads to severe saturation or dehydration, or a heavy spring thaw is followed by a snap freeze, then the soil can shift dramatically. This is what most often causes severe damage to a property and its foundation, due to the sudden application of pressure or removal of support. 

Saturated soil, for example, will swell. This causes it to exert pressure, of course, but it also leads to the texture becoming soft and marshy. As such, this issue can cause cracking either through excessive pressure or by allowing the property to start sinking. By contrast, dehydration causes expansive soil to shrink and crack. This can lead to large voids opening and removing support from sections of your foundation. When this happens, sections of a foundation may break away and sink as a part of a process known as settlement. 

Soil Washout and Erosion 

If you have loose or weak soil, your property may be more vulnerable to damage because of soil washout and erosion. These processes are, at their core, processes of soil removal caused by extreme weather or powerful force exerted either by wind or running water. Erosion is caused by high winds and, as such, tends to be limited to the topsoil. 

Soil washout, by contrast, can be caused by underground water sources and flooding. As such, it can wash away soil from below the surface. This is a common cause of sinkholes. Both processes are most likely to affect soil that is already unhealthy and will make it less healthy over time. If left to grow unchecked, then washout and erosion can lead to land becoming fallow. 

Of course, a more immediate issue for homeowners is how soil washout and erosion can cause voids to open under a property. This can cause foundation settlement and, by extension, lead to cracked and sinking floor slabs inside a home. 

Poorly Compacted Backfill Soil 

Building a property requires the excavation of a much larger area than most people are aware of. Once the foundation and foundation walls have been built, there is a lot of space left to fill in; the soil that was excavated is put back in place to ensure that the foundation is not exposed to the elements. 

The problem is that backfilled soil is much more loosely-packed than virgin soil, no matter how hard contractors try to compact it once more. As such, this area around a home is more likely to collect water at a rate that the soil around it cannot cope with, leading to the creation of a clay-bowl. 

This issue can lead to many problems, but foundation movement and subsidence are the most common. While these are serious issues on their own, they are also some of the most common causes of sinking or cracked floor slabs in a home. 

In Chattanooga, TN, cracked floor slabs can be a problem sign for each of these issues. The only way to figure it out is by contacting a professional to assess your home. To do this in a prompt and timely manner, you will need to learn to recognize the other problem signs associated with these issues (and cracked or damaged floor slabs in general). 

Cracked Floor Slabs


Cracks in your property’s floor slabs can come about for several reasons, but when you break it down to the simplest level, it is all about pressure and support. If you have too much of one or not enough of the other, then your floors will become damaged. 

Hydrostatic Pressure 

Excessively strong hydrostatic pressure is a huge problem for any home and is connected to an extensive number of issues and forms of damage. Cracked, uneven, or sinking floor slabs are just one example of the issues that can come about because of excessively strong hydrostatic pressure. Of course, all homes deal with some level of hydrostatic pressure because this is merely the weight of the water in the soil around a home. 

However, all structures have a level of pressure at which they can no longer withstand the weight and pressure. Additional sources that can add to this include heavy rainfall, flooding, and underground water sources. Anything that impacts the level of the water table, too, will cause sharp increases in hydrostatic pressure and could damage the walls of a property as well as its foundation and flooring. 

Lack of Support 

Floor slabs that are sinking as well as cracking are more likely to be caused by some downward movement in a property’s foundation. This can be caused by several things but really comes down to a lack of support from the soil beneath your home. Issues like settlement are most often caused by wash out, erosion, and shrinking in soil, but there are other possibilities. 

A sudden and strong flood can cause a property to move laterally. This occurs because of the force of the flood water but is most likely to affect homes that also sit on loose or weak soil. Lateral movement can cause many kinds of damage, including rupturing water and sewage mains. Leaving certain sections of foundation without support is just one possibility. 

Sinking and cracked floor slabs can be lifted, set, and repaired with the right tools and skills. In most cases, the SettleStop Slab Pier system will be recommended by professionals. This is the go-to solution for several reasons. 

Longevity and Durability 

Dealing with damaged or sinking floor slabs can seem quite daunting, especially when the underlying causes are structural in nature. Professionals commonly suggest slab piers as a solution for this kind of damage because slab piers offer a permanent solution to the problem. They can do this because they are designed to address the root cause of the issue. 

When cracked floor slabs are caused by structural damage to the property’s foundation, the issue is often based in the soil underneath the home. Slab piers lift, set, and hold damaged slabs in place by transferring their weight to competent, load-bearing soil below the frost line. This gives them stability and you peace of mind. 

Cost Effectiveness 

Another good reason to choose slab piers as a replacement method for your cracked or sinking floor slabs is that they are a far more cost-effective solution than simply replacing the floor slabs. While replacement can seem tempting because of the ‘like-new’ finish that it offers, it is a far less effective choice on all fronts. 

After all, replacing the slabs that have cracked will be time consuming and expensive. Beyond that, replacement is ineffective unless paired with a solution that addresses the underlying cause of the damage. If it is not dealt with, then the cracks and unevenness will simply reoccur at a later date and cost more money in the long run. 

No, we do not recommend that you try to install slab piers alone. As well as being difficult and requiring specialist skills, slab pier installation can be dangerous to those who do not know what they are doing. Choosing professional services, by contrast, ensures that you get the right results every time. 

The Dangers of DIY 

Trying to deal with any structural damage by yourself is something that we would never recommend for several reasons. First, you must keep in mind that structural damage of any kind is complex and tends to have a number of underlying factors that must be considered. If you do not account for all of them, then any solution that you deploy will be fundamentally flawed and ineffective overall. What’s worse, is if the structure of your property is also damaged, trying to undertake DIY repairs could well lead to collapse in certain areas of flooring. This is not just damaging but actively dangerous as well. 

Assuming you are able to accurately diagnose the cause of your cracked floor slabs and identify all the underlying causes, you will still need to have the skills, tools, and equipment to deploy an effective solution. Non-professionals are unlikely to have everything that they need to do this for a number of reasons. Trying to do the work alone could lead to a bad result or even injury to your person. As such, it is best to contact a professional if you want to get effective, long-term results that also look good. 

Why Professional Services are Best 

If you choose to hire a professional, then you are far more likely to get high quality, durable results that prevent the recurrence of damage. This is because professionals are professionally trained and have experience, but also because they have the right tools and equipment to deal with whatever underlying issues are at work in your home. This ability helps them react to whatever secondary and tertiary issues that arise because of, or in connection with, your cracked floor slabs. 

Not only do professionals have the skills and experience to react, but also, they have access to the best products on the market. You see, while a DIY enthusiast will have to make do with what they can find over the counter in their local hardware store (or online), professionals can buy from industry supply stores and even direct from the manufacturers where necessary. As such, they can guarantee a durable and high quality result every single time. This is a guarantee that no DIY enthusiast can offer, no matter how skilled they are.  

Other Problem Signs to Watch Out For 

Learning to spot additional problem signs may help you to better understand just where the cracked floor slabs in your home are coming from. These problem signs are not the only signs that can be connected to cracked floor slabs and their underlying causes, but also, they are the most common and easy to spot: 

Visible Sinking or Unevenness 

If your damaged floor slabs are also visibly uneven or sunken, then this is a strong sign that there are voids beneath the slabs. If this is the case, then the unevenness will only get worse over time, and the slabs could eventually split and sink entirely. If this happens, then the floor around the area could become damaged even if it were stable before. 

Sunken or uneven slabs also present a heightened risk of accidental injury, especially to those who have issues with mobility already. As such, it is best to act quickly when you see this kind of damage in your home. 


If your property’s flooring becomes overtly cracked, then it may start to fragment. This happens when cracks effectively separate a chunk of stone from a slab, leading to it breaking away from the main surface. 

This is not only a sign of advanced damage and degradation in a floor slab, but also it will create a serious tripping hazard by making the surface of the floor unstable and uneven. This could result in severe injury to anyone who happens to fall. 

Floor and Wall Gaps 

Your flooring should be firm, stable, and flush with the walls that they are attached to. If you see gaps forming between the floor and the walls, then you should act very quickly. This is a sign that your flooring is sinking or sagging. 

If your floor slabs are sinking or sagging as well as cracking, it is time to contact a professional. Once the flooring has cracked and started to sink, the problem will only get worse, and it is highly likely that it will do so at an exponential rate. 

Pooling Water 

Pools of water or patches of dampness around cracks in your floor slabs are a sign that the cracks in question go all the way through the slab and may originate in the foundation of the property. This will allow groundwater to seep through and into the property, which can cause a lot of secondary damage. 

For example, pooling water can cause water damage to organic surfaces and furnishings as well as create a higher level of relative humidity. This will make the environment in your home uncomfortable, certainly, but unhealthy as well. 

Mold and Mildew Formation 

A damp and humid environment will make the formation of fungal growths like mold and mildew far more likely. While most forms of mold are harmless and will not cause damage to the structure of your home, there are some that can be actively toxic and have health implications for you and your family. 

Black mold, in your home, is a seriously toxic form that can cause rashes, infections, dizziness, respiratory problems, and even seizures. If you already have conditions that affect your lungs and immune system, then exposure to black mold could be potentially lethal and lead to hospitalization. 

If you see any of these signs, please do not hesitate to contact a professional. Acting quickly could make all the difference when it comes to protecting your home from avoidable secondary and tertiary damage. Getting professional help from a team with the right skills and experience will ensure that you also get the right results. 

Expert Slab Lifting and Repair From AFS Foundation & Waterproofing Specialists 

Have you seen cracked floor slabs around your home? Are there uneven patches on your floor? If so, then it is time to contact AFS Foundation & Waterproofing Specialists to arrange a free inspection appointment. These appointments are designed to ensure that our team really understands what is happening in your home before they suggest how to fix it. There is no obligation to book repairs with us after your inspection appointment. We are pleased to service Birmingham, AL, Huntsville, AL, Mobile, AL, Nashville, TN, Chattanooga, TN, and Knoxville, TN. 

Of course, there are some benefits to these appointments for you, as a homeowner. Firstly, they allow you to speak with a professional about your home and the causes of the cracks in your flooring slabs. Secondly, this appointment comes with a written estimate for the cost of repairs. This means that you can count on having a better understanding of your home’s situation and what it will cost to rectify it. This will enable you to make an educated choice about how to proceed. 


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