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Wall Crack

If you have a wall crack that has been giving you concern, call a professional. The nature of the repairs that are needed will depend on the underlying issues at work.

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Foundation Repair

Finding cracks in your foundation walls is always concerning, even when they are small or seem to be stable. However, a wall crack that is deep, wide, or actively growing is another issue altogether. These kinds of cracks are a sign of ongoing pressure and strain that you should never ignore. Acting quickly when you see this problem sign could save you time, money, and a lot of stress in the long run, especially if you have the right help. 

Here at AFS Foundation & Waterproofing Specialists, we have two decades of experience in dealing with issues just like this in Huntsville, Alabama, and surrounding areas. When you have the AFS team on your side, you can expect a swift and effective repair process with optimal results. Here is what you need to know about wall cracks, what they mean, and how they can be addressed. 

Problem Signs: What a Wall Crack Can Mean

At the most basic level, a wall crack (or any kind of crack, really) is a sign that there is pressure at work that the wall (or your home in general) is struggling to cope with. The source of this pressure can take many forms, but the most common are: 

Excessive Hydrostatic Pressure 

All homes are subject to some level of hydrostatic pressure. This is just a measure of the weight of the water in the soil and the amount of pressure it brings to bear on the walls and foundation of a home. If your property has a basement, these walls will endure most of the hydrostatic pressure around your home and are likely to show cracks first. 

You are likely to find a wall crack in your basement wall first because hydrostatic pressure exerts lateral pressure, which puts the already low (proportionally speaking) tensile strength of concrete to the test. That does not mean that properties with crawl spaces are immune to this pressure. 

Incredibly strong hydrostatic pressure can also cause cracking, fragmentation, and damage to a property’s foundation when it is left unchecked. This will lead to serious structural damage to every area of your property over time. 

Defects and Flaws 

Though it is unlikely, there is also a chance that a wall crack in concrete has been caused by a fundamental flaw or defect in the wall itself. Concrete is just a mix of water, aggregate, and cement and if the mix is poorly proportioned, it can lead to the cement being crumbly, weak, or cause the formation of large fault lines throughout the wall. 

Defects in bricks are less common still, so it is more likely that you will find a crack in the mortar between bricks. However, if you do see cracks through one or two bricks, it is likely to be an issue with those individual bricks. If many bricks are cracked in a uniform fashion, however, you should act quickly and call a professional. 

Foundation Damage 

Foundation damage is the one kind of damage that is truly guaranteed to cause serious issues throughout the whole structure of a property. If your foundation is damaged or unstable, you are sure to see wall cracks and flooring issues throughout your property as the issue progresses without intervention. 

The most common kinds of foundation damage are settlement and subsidence. Both are forms of sinking that will cause fragmentation and cracking in the concrete floors at the base of your property. However, over time, they will also lead to cracks in the walls and cause general instability.

Lateral Movement  

Lateral movement in a property’s foundation is uncommon, but there are some cases in which it is likely. Extreme flooding, for example, and saturation of already loose or weak soil can lead to a property shifting laterally. When this happens, it is likely that your walls and flooring will crack. 

There is also a high chance that this kind of movement will cause damage to the electric and plumbing systems in a house. In fact, a sudden plumbing flood or lead may be one of the first signs of lateral movement that you see. 

These are just some of the issues that a wall crack in your home can signify. It is important to note the placement of the crack and how it is presented, as this can tell you a lot about what is going on under the surface. 

Different Types of Wall Cracks 

Broadly speaking, there are two kinds of cracks: active and stable. While the first is a problem sign and a warning for more trouble on the way, the other presents no active danger to the property in question. 

Stable Cracks: Settling, Shrinkage, and Past Damage 

To put it simply, stable cracks are those that are no longer growing or changing in shape, width, or depth. They can form for several reasons, but do not represent active issues within a home. They may have been formed by a significant issue in the past and simply not repaired. 

The probable cause depends on their size. Hairline cracks are most likely to be caused by the natural shrinking of settling concrete and the settling on a newly built structure. Not to be confused with settlement, this is a process of relaxation that is perfectly natural. For reference, hairline cracks tend to be no more than 1/16” wide and should maintain a consistent width.

Active Cracks: Ongoing Pressure and Movement 

Active cracks, sometimes known as spreading cracks, are those that are still actively growing in size. These can vary in size and depth but will change fairly frequently, depending on the nature and severity of the pressure that is being exerted on the property. 

The most common causes of an active or spreading wall crack are hydrostatic pressure, foundation damage, defective materials, poor or insufficient support, and general movement in a property’s structure. Whatever the cause, you should investigate spreading cracks quickly and thoroughly to ensure that they do not have a chance to grow further and cause serious issues throughout your home. 

The process of dealing with cracks like this is complex and can take many forms. It is imperative that the underlying causes of the pressure are dealt with fully before the cosmetic damage (the crack) is repaired.

Problem Signs of Secondary Damage 

A singular wall crack may not seem like a huge issue, even when you consider the underlying issues that it may represent, but you should not underestimate it. Even a small crack can cause secondary damage to form in your home in several ways. These are the problem signs of secondary damage that you should be aware of: 

Humidity and Condensation 

Humidity and condensation are sure signs of damage to your property in Chattanooga, Tennessee, even if you cannot yet see cracks or leaks, but they can also contribute to secondary damage. They do this by creating a vicious cycle of dampness and humidity that will not only allow fungi and bacteria to spread unchecked but also hamper your home’s HVAC. 

Humid air is harder to condition than arid air and means that your HVAC system will have to work harder to produce the same results. As the dampness progresses, it will become more difficult, and your HVAC will produce less consistent results while experiencing accelerated deterioration. This will increase your energy bills too. 


Mold and mildew go hand in hand with dampness and humidity, and while they are benign to the structure of your home, they can be very damaging to your health and well-being. Black mold is toxic to humans and animals. Prolonged exposure can cause infection, irritation, dizziness, fainting, seizures, and respiratory problems. 

You will recognize mold by the smell and patches of discoloration that it causes, but if you think there is mold in your home, you should avoid it and call a professional. 

Floor and Wall Gaps 

If there are gaps between your flooring and walls, this is a sign that there is something serious at work in your home. When paired with cracks in the walls, it is a sign that the walls are moving or being pulled away from the flooring because of a huge amount of pressure. 

If you cannot see wall cracks, it is possible that the damage lies beneath the floor. Damage to the joists and beams that support the floor, for example, can cause gaps to appear between the floor and walls as the floor sags. 

Cracks in an interior wall

Bowing or Leaning Walls 

Bowing walls are a significant issue you should not ignore. Most often caused by hydrostatic pressure or overloading, a buckling or bowing wall is one that is starting to deviate from its intended position. It may start to lean at the top or bottom, or bulge in the middle. The cracks that form and spread because of bowing walls tend to be horizontal. 

If left unchecked and unfixed, a bowing wall will only deviate and, eventually, collapse. If this happens, it will likely cause damage to your floors as well. A more worrying prospect is the danger that this presents to your health and well-being. 

Sagging Flooring 

You might notice that your flooring is uneven or is starting to sag as a result of some kind of damage or deterioration in the floor itself or the joists that support it. If you see this as well as cracks in your walls, it is possible that foundation damage is one of the underlying causes. 

Acting quickly will prevent the collapse of your flooring and save you a huge amount of time, money, and worry in the long run. Call a professional as soon as you feel springiness or sagging underfoot. 

Each of these problem signs can be connected to several secondary issues that might result from having cracks in your property’s walls or flooring. Many of them are connected to dampness because cracks in the structure of a property increase the risk of flooding, dampness, and high relative humidity dramatically.

Wall Cracks


Cracks in your walls are never ideal, but some are more dangerous than others. Knowing how to tell when a crack represents a real danger is vital to protect your home from avoidable damage. 

Depth, Width, Length 

The size of a wall crack is important in determining its potential impact (as well as the most likely cause). Hairline cracks are those that are too small to fit a credit card or business card into. They tend to be less than 1/16” in width no matter their length and should be consistent in width along their full length. These cracks tend to be caused by small movements in a property and represent no immediate risk unless they change in size. 

Cracks that are deeper or wider than hairline cracks are a more serious issue and always represent damage of some kind. This damage or issue could be past or ongoing, but any crack that is wide enough to slide a card into requires some investigation. The bigger the crack, the more pressing the need for attention (unsurprisingly), as the more likely it is to cause destabilization in your property. This accounts for longer and deeper cracks too. 


The second concern is whether the cracks that you have found are stable. A stable crack is one that has formed and settled fully, meaning that it is no longer growing in depth, length, or width and that it will not grow again unless acted on by an outside force. This covers cracks that were formed by issues that have already been resolved and those that formed because of the natural settling of a property. 

Active cracks, by contrast, are those that are still growing because of ongoing issues and pressures. These cracks can be any size, really. They are categorized by the way they grow, more than anything else. However, you should pay attention to the rate at which a crack is growing. The speed of its spread will give you an indication of the severity of the underlying cause of the damage. No matter the speed, however, you should contact a professional quickly. 

There are many homeowners who feel that it is best to wait until a problem becomes hard (or impossible) to ignore. We urge you not to do this, however, as there could be dire consequences for ignoring the needs of your home. 

Delays Are Dangerous 

The problem with waiting until issues like this get worse is that you cannot really be sure what the underlying problems are until an investigation has been completed. So, while the cracks may be caused by defective concrete or general movement in the structure of your property, they could equally be caused by foundation issues. Depending on the issue, you could end up in a lot of trouble. 

Foundation issues, for example, are notoriously damaging and will only get worse over time. In fact, they get worse at an exponential rate. This means that waiting even a short while after you spot the problem signs of damage could be disastrous for your home and even your health. In fact, any structural damage could lead to collapse if you ignore it for long enough. 

Acting Quickly Saves Time and Money 

As well as avoiding collapse and serious structural damage, acting quickly in the face of a wall crack can save you time and money. Any issue (especially a structural issue) is easiest to rectify and repair when it is dealt with quickly. Dealing with a foundation that has only just started to sink, for example, is far easier than trying to deal with a foundation that has already shifted considerably. 

Likewise, the cost of stabilizing or straightening a bowing wall will be lower when the wall has deviated by only a small amount. Secondly, repairs to issues that are still in their infancy tend to be less invasive and complex because there will have been less time for secondary issues to form. This keeps your bottom line low and the damage localized. It is best to deal with a wall crack as soon as you see it.

Whether you have seen just one crack in your property’s walls, or there are many, you should act quickly and call in a professional. We understand the temptation to save money via DIY, but this is rarely the result when non-professionals try to deal with structural issues alone. 

DIY Does Damage 

Whatever has caused your wall cracks, the damage is likely to be structural, at least in part. As such, it is very unwise to try DIY. Here at AFS Foundation & Waterproofing Specialists, we tell our clients that DIY should end where structural repairs begin. This is not just to ensure quality results, but to protect your health and safety. 

Most of the repair methods that are most effective when it comes to dealing with structurally unstable walls or fragmented foundations require some invasive measures. The equipment required to do this is heavy and dangerous, but the real danger lies in the possibility of causing a collapse by putting too much strain on already damaged parts of the structure. This could be lethal to anyone in the vicinity. 

Professional Tools Are the Best 

Professionals know just what it takes to repair a damaged wall or foundation while maintaining structural integrity and ensuring the safety of all people in the house, as well as their own. They can do this because they have the right tools and products, but most importantly, the experience to use them to provide the absolute best results. Better still, they can adapt to new issues where needed while maintaining speed and quality. 

This adaptability is important because the repair of structural issues rarely runs just the way it is expected to. The likelihood of sudden complications is more of a certainty and knowing how to act appropriately is a matter of experience—something that most DIY enthusiasts simply do not have. Add to this the fact that professionals have everything they need on hand already, and there is a high likelihood that a professional repair will cost less in the long run.  

Choose AFS Foundation & Waterproofing Specialists for Foundation Repair 

If you have noticed a wall crack (or many wall cracks) around your home, it is time to act. Even one or two cracks can be a sign of serious issues at work in your home. If they begin to spread, the likelihood of secondary damage will increase exponentially. Getting professional help quickly can make all the difference when it comes to the cost of repairs. 

Here at AFS Foundation & Waterproofing Specialists, we are happy to serve Birmingham, Huntsville, and Mobile, Alabama, and Nashville, Chattanooga, and Knoxville, Tennessee. We help homeowners address damage to their foundation walls (as well as the wider structure of their properties). The process starts with a free inspection appointment and a written estimate of all costs associated with our suggested repairs. Do not worry, however; this appointment comes with no obligation to book work through us. 


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