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6 Causes of Concrete Damage and How to Spot Them

sinking concrete steps

Concrete is the single most popular construction material in the world for a number of reasons. First and foremost, it is strong, resistant to extreme temperatures, and resistant to fire. It is also incredibly durable in the face of weather events like high wind and flooding. Properties that have a heavily concrete-based structure will be less likely to take damage as a result of freak weather, but there are some very simple issues that can undermine them. 

Concrete is very heavy, it is porous, and once set, can become brittle. It cannot bend or stretch in any considerable way. This makes it susceptible to a number of issues that will result in cracks forming and spreading through a concrete structure with alarming speed. As a homeowner, it can be daunting to notice cracks in concrete surfaces of any kind for just this reason. Depending on the underlying problems, the repair bills could be incredibly costly. 

Common Causes of Damage to Concrete 

The precise causes and nature of damage to concrete depend largely on the type of structure it is a part of. However, there is one common factor in most serious forms of concrete damage, and that is problems in the soil that supports a structure. For structures that are particularly exposed, extreme weather might also cause damage, at least on a superficial level. 

1. Soil Washout and Erosion 

Soil washout and erosion are common problems around Raleigh and Winston-Salem, NC, because of the high levels of loose sandy and loamy soil in this area. When loamy, sandy, or otherwise light soil that is minimally absorbent and expansive becomes unhealthy, it is prone to being swept away by water or wind. Erosion and washout can affect soil both from above and below, but it is most common for soil to be swept or washed away from the top. Topsoil is far more exposed, after all. However, soil that is very saturated can also be washed away from beneath. 

No matter how erosion and soil washout take place, they pose a real risk of damage to the concrete around a property. This is because of the way in which they leave voids underneath a concrete structure. When this happens the pressure and weight of the concrete will slowly overwhelm its tensile strength and result in it cracking and sinking into the ground. This can happen to a property’s foundation, but also to concrete driveways and sidewalks. For exposed structures like this, however, erosion is fairly visible and can be recognized by gaps forming under the edges of the driveway or concrete slabs. 

2. Expansive Soil 

Expansive soil is a huge issue for any property that rests on it. Expansive soil can take many forms, but it is at its heart a heavy, absorbent soil that reacts dramatically to the presence or absence of water. Generally clay or peat-based, these soils swell and become soft when they are saturated. This can exert a huge amount of lateral pressure on a property’s foundation walls and lead to issues like bowing walls. It will also become marshy and lose some of its ability to bear weight when saturated. This leads to concrete surfaces and structures sinking. 

When dehydrated, however, expansive soils can shrink dramatically and form huge cracks and chasms. This process will leave any properties and structures that rely on support from the soil without the base that they need and result in damage. Properties that find themselves over voids created by shrinking soil will quickly undergo a process of settlement that is incredibly damaging. 

3. Weak Soil 

Weak soil is more prone to issues like soil washout and erosion, of course, but it can cause problems all on its own as well. Heavily sandy soils, in particular, can cause a huge amount of damage to a property simply by shifting when put under certain kinds of pressure. You see, loose, non-absorbent soils that are excellent at draining water are also less adept at sticking together when large amounts of water run through them. 

So, while you will rarely have to deal with perimeter saturation in sandy or very light loam-based soil, you may find that your property starts to shift during intense periods of rainfall or thaws after heavy snowfall. Another possibility is that a property will begin to sink into the ground as the soil underneath it shifts. 

4. Repeated Freeze/Thaw Cycles 

Repeated and sudden freeze/thaw cycles are incredibly damaging to most structures, but exposed concrete surfaces like driveways and sidewalks are particularly vulnerable to this. Concrete is resistant to fire, flooding, and extreme temperatures, but it has a few vulnerabilities. As well as lacking tensile strength, concrete is porous. When faced with persistent dampness, it will absorb water. 

When sudden snap freezes and thaws repeat over and over, the water inside concrete expands and shrinks over and over. This can cause damage to the surface. The damage tends to be cosmetic at first; pitting, flaking, scaling, and cracking are common. However, when left unaddressed, these problems can quickly snowball into more serious issues. 

5. Tree Root Incursion 

Trees create huge and powerful root networks that are incredibly beneficial to the health of the soil around them. However, these strong and persistent roots can also cause huge problems for any structure that they encounter. Tree roots are known to invade sewage lines, damage water mains, and even cause damage to property foundations. 

As such, concrete driveways and sidewalks are incredibly vulnerable to damage from invading tree roots. When tree roots cause concrete to crack and heave, it will be necessary to first remove the offending roots before repairs can be undertaken. 

6. Frost Heave 

Frost heave is a rather unique issue that is caused by a combination of expansive soil and sudden cold snaps. When a snap freeze hits saturated soil, the water will quickly expand. However, if the cold snap is severe enough, the top layers of soil will freeze solid before the lower layers of soil are affected. The result is that this shelf of frozen soil is forced upward in chunks as the lower layers freeze, exerting pressure on surfaces above. If the surface or structure is particularly light, it could heave upward and crack, forming unsightly bulges. 

This is easy to spot but relatively difficult to fix unless you have the experience, skills, and special tools that are required. 

When you notice sunken, cracked, or otherwise damaged concrete around your property, it is important that you contact a professional to assess the situation properly. There are many different warning signs of damage that an expert will be able to read effectively. 

Recognizing Problem Signs 

If you as a homeowner are able to recognize early warning signs of concrete damage, however, you will save yourself a lot of stress, mess, and money in the long run. Of course, there are dozens of warning signs, many of which only display themselves in particular scenarios or environments. As such, it is far more effective to focus on recognizing general signs of unhealthiness or damage in and around your home. 

Red flags you should not ignore include, but are not limited to: 

1. Perimeter Saturation 

While all properties are designed to withstand hydrostatic pressure and moisture to some degree, there is always a breaking point. If you can see visible saturation around your property perimeter, this is an early warning sign that you should not ignore. In fact, if you can deal with it early you might avoid damage altogether. 

2. Bald Spots in Your Yard 

If you see bald spots in your lawn forming for seemingly no reason, you should contact a professional as soon as possible. This is a sign that the soil is becoming unhealthy as a result of erosion or washout. If left to grow, this will result in more serious erosion and impact your property as a whole. 

3. Spreading Cracks 

Cracks that are visibly growing and spreading are a serious warning sign no matter what surface you see them in. You should never ignore spreading cracks, even if they seem relatively limited at first. 

4. Sunken Concrete Sidewalks or an Uneven Driveway 

Unevenness, sinking, tilting, or sagging in any concrete floor, sidewalk, or driveway is a warning sign that the soil underneath it is seriously unstable. These visible signs of damage, therefore, are not likely to be the only issues at work. Having the problem investigated quickly will minimize damage. 

5. Sinking Foundation 

If your property begins to look visibly uneven or tilted at any point, you should prioritize a full investigation of the foundation immediately. This is never a good sign. 

These are just some of the many warning signs of damage to concrete surfaces and structures, but they are also the most obvious and serious. If you see even one of these red flags, do not hesitate to call in an expert. 

Is Concrete Actually Weak? 

Concrete is, at its heart, an engineering material that simulates the main properties of rock, while offering more flexibility and malleability when still in liquid or paste form. Made from a blend of aggregates, cement, and water, concrete can be molded into almost any shape when it is still wet, but it loses this flexibility when fully set. 

While concrete is incredibly strong and durable when it comes to bearing weight, dealing with strong winds, and even coping with extreme temperatures, it has two serious weaknesses.

  • Firstly, concrete is incredibly heavy, which makes it particularly vulnerable to sinking and settlement when the soil under it is overly wet or loose. 
  • Secondly, and perhaps most importantly, concrete simply cannot stretch. While concrete has huge compressive strength and will actually gain load-bearing capabilities over time, it has almost no tensile strength. This is because its tension-compression ratio, at about 10 to 15%, is very skewed. This means that concrete can withstand roughly 10 times more pushing or compression force than pulling force or tension. This makes it perfect for rigid structures, but prone to cracking when forced to bend. 

Concrete Cannot Stretch FAQs

If you have noticed damage, cracking, or sinking in your driveway or the concrete sidewalks around your home, it is time to consider a professional inspection. There are many things that can cause uneven concrete; all require intervention. 

Defects in the Concrete 

Concrete is, in essence, just a mix of cement, water, and sand. The precise makeup of the soil aggregate used in making cement may change, but other than that concrete can only be tailored by changing the ratios of each material. This makes concrete uniquely easy to tailor to the needs of a specific project, but it also renders it vulnerable to defects as a result of miscalculations. 

Miscalculations in the ratios of water to cement, for example, can result in a concrete mix that is weak and prone to crumbling. This is not the only potential issue, however. Concrete can also be damaged when it is being laid. Certain methods of compaction, like hard troweling, can lead to an inconsistent density across the surface of a concrete structure. Likewise, improper or insufficient curing can lead to serious damage in the long run. 

Unstable Soil 

Assuming the concrete itself was properly formulated, mixed, and deployed, the damage is most likely to be caused by issues in the soil beneath a structure. This is true for internal and external concrete surfaces. Concrete damage that is caused by issues in the soil is very common around Raleigh and Winston-Salem, NC, largely due to the nature of the soil in this area. 

While more coastal areas might see loose and unstable soil that is sand-based (and therefore prone to washout), this area has soil that is more expansive and absorbent. This can lead to concrete surfaces sinking or settling as a result of soil saturation and expansion or dehydration and sinking. Concrete lifting services will need to be tailored to suit the soil in order to be successful.

Protecting your concrete surfaces, whether inside or outside of your home, requires careful moisture management and seasonal maintenance. 

Keep Your Drains and Gutters Clear 

Performing basic, seasonal and annual maintenance tasks, both inside your home and in your yard, is one of the best things that you can do to protect concrete surfaces and sidewalks all around your property. Internal and external concrete surfaces, floors, sidewalks, and driveways alike are most likely to be affected by extreme soil saturation around your property’s perimeter. As such, doing what you can to keep your drainage systems in good repair is important. 

In this endeavor, you should take time to clear your drains and gutters of debris and buildup every fall and spring. This will ensure your gutters and drains are in the best possible condition and prevent overspill in all but the most extreme of circumstances. Secondly, you should make sure your downspouts are properly placed to direct water away from your foundation. Finally, make sure any interior drainage systems you have in place do not dump water directly outside your home. 

Improve Yard Drainage 

If you are completing all necessary maintenance and cleaning tasks, but you are still noticing heavy saturation around your property, it may be time to update your waterproofing measures. Even gutters and drain systems have a usable lifespan, after all. When you notice that your gutters and drains are experiencing a lot of overspill, or you see particular areas that are saturated, it is time to think about upgrades. 

There are a number of things that you can do to improve drainage around your home that go beyond installing new drains. In fact, planting the right kind of flora around your yard could seriously improve soil drainage and even prevent erosion and washout. Whatever you decide to do, however, we urge you to contact a professional to talk about your options beforehand. This will ensure you get a solution that is actually tailored to your situation. 

To put it simply: no, you cannot lift damaged or sunken concrete alone. This is a specialist and potentially dangerous task that can go wrong very easily. 

DIY Doesn’t Work 

DIY skills are incredibly useful in many cases, but there are times when it is far better to step back and let the specialists step in. Sunken or damaged concrete surfaces represent one such time. Concrete lifting and repair are specialist tasks that require professional experience, skill sets, and tools for quality completion. This is absolutely key if you want to maintain generally low repair costs for your home. 

If you try to undertake these repairs alone, you run the risk of either covering up the true cause of the damage, which will result in recurrence or causing more damage. This will not only mean you have to address the same problem more than once, but it will actually raise the overall cost of your repairs. Finally, the equipment and tools used to lift concrete can actually be dangerous to your health and well-being if used incorrectly. 

The Benefits of Professional Help 

One of the largest benefits of getting professional help when it comes to concrete lifting is the fact that it is far safer than undertaking DIY repairs. Of course, there are other benefits to professional work that should not be overlooked. At the top of the list is the quality of the result that professional concrete lifting services will give you; experience yields unparalleled results. 

This is made possible by the fact that professionals have access to the very best products and tools. Certain concrete lifting products may not be readily available through hardware stores but instead sold through wholesalers or direct from the manufacturer. Professionals will have access to these products as well as the knowledge and skills required to provide you with a permanent solution the first time around. This makes professional help a solid investment. 

Choose Tar Heel Basement Systems for Expert Concrete Lifting Near You! 

Tar Heel Basement Systems has been serving Raleigh and Winston-Salem, NC, since 2003. Over the years, we have helped thousands of homeowners identify and address the underlying causes of concrete damage in and around their homes. From foundation repair to concrete lifting, our team has the skill and expertise to deal with problems of all sizes. If you have concerns about concrete around your home, please do not hesitate to contact our team today to schedule a free inspection and repair quote.

Michael Wilcher

Michael Wilcher

Michael Wilcher is the Content Lead at Groundworks, helping us to answer all of our customers biggest questions about foundation repair, basement waterproofing, crawl space encapsulation, and concrete lifting. In his free time, Michael enjoys collecting vinyl records, watching Formula 1 Racing, and reading philosophy. He holds an MPhil from the University of Cambridge.

*Disclaimer: “Concrete leveling” means the process by which cracked, uneven concrete is stabilized, and in many cases lifted, by means of PolyRenewal™ polyurethane foam. Tar Heel Basement Systems does not guarantee that PolyRenewal™ can make your concrete perfectly level.

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