Concrete Cannot Stretch

Concrete is one of the oldest construction materials in the history of the world. For example, evidence of concrete or concrete-like substances can be seen in ancient Roman buildings and in buildings in Syria and Jordan at around 6500 B.C. 

The fact that concrete, or some form of it, has been in use for so long is a testament to the incredible versatility, strength, and durability of the material. There is one huge problem with concrete, however. Concrete cannot stretch or bend, and this makes it incredibly susceptible to certain kinds of damage. Cracking, sinking, and crumbling are just some of the main issues that can affect concrete structures in Missouri. 

Concrete 101: What It Is and Why It Cannot Stretch 

Concrete is, at its heart, a type of man-made stone that has been favored for use in construction since roughly 6500 BC. Made from a mix of rock aggregate, sand, and water, concrete is very flexible when wet and can be molded into just about any shape, but loses this flexibility when it hardens. Concrete can easily withstand wind, rain, and even fire (though it is porous and will absorb water over time). That is why it is one of the main components of most large buildings around the world. 

What Concrete is Made of Affects its Durability 

When making concrete, the ratio of water to cement matters, as does the type of aggregate used. The wrong ratio of water and cement, or the presence of certain minerals in the aggregate, can make concrete far more prone to damage and deterioration in a relatively short period of time. This can cause a number of issues including, but not limited to: 

• Flaking 
• Pitting 
• Staining 
• Spalling and Scaling 
• Cracking 
• Efflorescence 

Over time, these issues can of course increase the likelihood of the surface succumbing to more serious structural issues, like subsidence. 

Concrete is Brittle 

The trick to good, durable concrete structures is to figure out just what kind or consistency of concrete is needed, and where it is going to go before it is even mixed. This is key because once the concrete has been mixed it is on a time limit. Once it has been laid, it will start to set, and once it has started to set, it should be disturbed as little as possible to ensure an even distribution and density. Once the concrete is fully cured and set, it is incredibly strong and tough, but the pay-off for this is that it loses its former flexibility and becomes quite brittle. 

This is why most concrete used in construction today is reinforced. Reinforced concrete usually has a skeleton of steel inside of it. This makes it slightly more flexible, as well as adding extra strength and resilience. This is only done in vertical structures, however. Concrete sidewalks, driveways, and flooring are rarely reinforced. 

What Can Damage Concrete Surfaces? 

Because of its unique strengths and weaknesses, there are a specific set of things that can really damage concrete surfaces. When it comes down to it, it’s usually a matter of pressure. Assuming that the concrete in question was mixed and laid well, that is. Concrete is not like wood, after all. Fire, water, and extreme wind do very little to concrete structures unless they are already badly damaged. Temperature and pressure, however, are other matters entirely. 

The main causes of damage to concrete foundations, sidewalks, and driveways tend to originate in the soil underneath the structure. This is not always the case, of course, but it is very prevalent. 

Freeze/Thaw Cycles 

Frequent changes in temperature can cause serious damage to concrete surfaces, especially when a series of snap freezes and thaws hit an area. This is likely to cause at least superficial damage, because of the porous nature of concrete and the way that water expands when it freezes. The repeated swelling and relaxing of concrete that has taken on a lot of water can cause bubbling, spalling, flaking, pitting, and even serious cracks to form. 

The best way to prevent this is to manage the amount of moisture that concrete is exposed to. For basement walls and property foundations, this means having the right drainage options and preventing perimeter flooding, but it can be harder for very exposed concrete surfaces like driveways. 

Expansive Soil 

Expansive soils are very likely to damage concrete structures and surfaces because of the way they expand and shrink, depending on their water content. Heavily clay-based and peaty soils, for example, are considered expansive and can cause damage to concrete surfaces very quickly, especially where a property has poor moisture management. There are three main issues that expansive soil can cause. 

Subsidence is a process of sinking caused by weak or marshy soil, whereby a structure starts to sink into the ground. This will generally affect heavy buildings and may result in concrete cracking because of the unevenness of the sinking process and the inflexible, brittle nature of concrete. As the weight of the property is unevenly distributed, the concrete foundation, floors, and walls will start to crack. Frost heave, by contrast, causes an upward motion that may crack very light structures like garages and concrete sidewalks. This is, of course, most likely to happen during snap freezes. 

Finally, settlement occurs as a result of soil shrinkage during periods of extreme dehydration. When dehydrated, expansive soils recede and can crack, leaving large voids that concrete structures gradually fall into when they fail to support their own weight. 

Weak Soil 

Weak soil can cause damage to concrete in much the same way that marshy or expansive soil does when it is very dry or completely saturated: by failing to provide the right level of support. Weak or unstable soils tend to be loamy or sandy, and they may be affected by underground water sources. This is most likely to cause sinking and subsidence in heavy structures, but almost any kind of concrete structure can be affected by this over time. 

Weak soils can be improved over time with care and effort, but this is a specialist task that will take the involvement of professionals if you get noticeable results with any kind of speed. 

Soil Washout 

Soil washout and erosion are also common causes of damage to concrete structures and buildings, and they are intimately connected to both weak soil and the weather. Loose, sandy soils, for example, are far more prone to washout than heavy, clay-based soils. If this kind of soil becomes unhealthy or fallow, a strong rainstorm or period of gale-force wind can simply wash or blow the topsoil away. 

Over time, this process will expose property foundations and leave voids underneath concrete driveways and sidewalks, leading to their cracking and sinking into the ground. Preventing or managing this process is, once again, all about keeping the soil healthy and ensuring there are good drainage systems in place. 

Any one of these issues can cause concrete surfaces and structures to become cracked, damaged, or sunken. The fundamental inability of concrete to stretch and bend is a factor in this process. When concrete becomes damaged or sunken, concrete lifting services are often the best solutions in both the short and long term. 

Concrete Cannot Stretch

FAQ's

Why Does Concrete Keep Cracking?

If you have noticed that concrete surfaces around your home are becoming cracked, there are many different things that could be causing this damage. This can range from lack of support to excess pressure and even design flaws. 

Concrete is Brittle 

Concrete is very strong and durable, but brittle and non-flexible by nature. This means factors that would cause metal or wood to flex and bend will instead cause concrete to crack or crumble. As such, the concrete surfaces around your home may be cracking as a result of pressure, lack of support, or even changes in temperature. What is most likely to do damage to concrete, however, is consistent change. 

Concrete is a material that likes stability. Consistent pressure, heat, or cold alone are unlikely to do damage to a strong, reinforced concrete structure, but constant changes will. For example, if there is an unseasonably cold fall or spring that causes repeated thaws and freezes, concrete structures will suffer as the water around them (and in them, thanks to concrete’s porous nature) expands and shrinks repeatedly. 

Defects Can Cause Damage 

If the concrete around your property seems to be cracking, flaking, sinking, or staining without obvious reason, it could well be a flaw in the concrete itself. This can take two forms: a defect in the mix or poor construction methods. Defaults in the mix refer to things like there being too much water in the concrete or the wrong type of aggregate. This can cause all kinds of issues, from flaking to efflorescence. 

Secondly, the concrete may have been laid improperly, disturbed after the setting process had started, or even inappropriately cured. This can also cause a wide range of problems, from the purely cosmetic (like staining) to the structurally damaging (like spreading cracks and spalling). Only a professional will be able to diagnose defects in the concrete itself. 

Can I Stop Concrete from Cracking?

As with most issues, it is best to take steps to prevent damage to the concrete surfaces in and around your home where possible. This can be easier said than done, and once damage has started to show, you will need to call someone who is able to do repairs. However, taking protective measures can still prevent an issue from snowballing while you wait for help. 

Moisture Management (Exterior) 

Exterior concrete surfaces are incredibly exposed, so protecting them is a little harder than protecting interior concrete floors and walls. Things like your property’s driveway and sidewalks, for example, are always in the firing line when it comes to climate and weather. As such, the best thing you can do for exterior concrete surfaces is managing the amount of moisture they are subjected to. This means keeping your drains healthy. 

Preventing perimeter saturation and flooding, as well as making sure that your yard has proper drainage, will make issues like frost heave, soil expansion, and flooding far less common. This will also minimize soil washout during heavy thaws and rainstorms. All in all, these measures will ease some of the strain on your property as a whole and minimize the chances of concrete damage. 

Waterproofing and Insulation (Interior) 

When it comes to your foundation and interior concrete surfaces, waterproofing and insulation are your best bets. By ensuring that any water that makes it into your home is expelled quickly (and taken beyond the property perimeter), you will not only prevent damage to your foundation and interior walls. You will help to protect the outside of your property too. 

Likewise, by insulating your pipes and your basement before adding things like a vapor barrier and sump pump, you will prevent extreme temperature fluctuations and minimize the risk of plumbing floods. This will also keep the relative humidity low, and protect your interior walls from mold formation and other forms of cosmetic damage. This actually has benefits for you that go beyond structural protection. A well-insulated and waterproofed basement is healthier and will even make your home more energy-efficient. 

Can I Repair Damaged Concrete?

It is possible to repair damaged concrete surfaces. In fact, it is possible to lift them back into place and even cover signs of cosmetic damage so they look as good as new. All you need are the right tools and skills. 

Concrete Lifting and Resurfacing 

When concrete surfaces are seriously damaged, there are two main things that will need to be addressed: the structural damage and the cosmetic damage. Structural damage will necessitate stabilization and probably lifting. In these cases, it is necessary to identify the underlying cause of the damage and mitigate that pressure before it will be possible to repair the concrete and make it look new once more. 

There are many possible solutions, but the most common are mudjacking and PolyRenewal™ polyurethane injections. If the surface is being damaged by deeper foundation issues, helical or resistance foundation piers may be needed to perform a full repair. Once the surface is stable once more, it will be possible to resurface the concrete to hide the evidence of damage. It is not advisable that you try this alone. 

Do Not Try DIY 

We understand that it is incredibly tempting to try to save money and time by addressing an issue alone, but we urge you to instead call a professional with the Foundation Recovery Systems team. We will attend quickly and guarantee a fair price (as well as a professional standard of repairs). Concrete repair and lifting are specialist tasks that require set tools, skills, and products that are not always available to even the most enthusiastic amateur. 

Trying to take on these repairs without professional help could actually be dangerous, too, thanks to the nature of the equipment and products you will need. PolyRenewal™ foam, for example, is quick, efficient, and cost-effective in the hand of a professional. If you mix it incorrectly, however, it can over-expand and cause irreparable damage to the concrete surface you are trying to fix. What’s more, it could cause damage to your person if not handled correctly. Likewise, foundation piers require heavy, expensive equipment for installation. All in all, it is far better to let us do what we do best. 

What Concrete Lifting Processes are Effective? 

The process for lifting and repairing a damaged concrete structure depends on the nature of the damage and its underlying causes. Broadly speaking, however, the solution changes depending on whether the concrete in question is a foundation or a free-standing concrete slab. 

Lifting a Damaged Foundation 

Lifting a damaged concrete foundation back into place can be undertaken with one of two products and is incredibly intensive. It used to be that serious foundation damage was addressed by lifting and relaying a property’s foundation in sections. This was not only incredibly expensive but very time-consuming and not very effective. Because it does not address the actual causes of foundation damage, this is more of a delay method than a repair solution. 

These days, foundation piers are the favored method of lifting a damaged foundation back into place. They not only lift it effectively but provide a stable and permanent solution by transferring the weight of a property onto competent, load-bearing soil. Helical piers are better for lighter properties because they set themselves in place by “biting” the soil. Meanwhile, push or resistance piers use the weight of a property to set themselves in place. A professional will be able to tell you which is best for your home if you are in need of foundation repair. 

Lifting Sunken Concrete Slabs 

If the concrete that needs to be lifted is an isolated concrete slab, a section of flooring, part of a driveway, or a part of a sidewalk, the process of lifting it back into place is likely to be far easier. In most cases, these structures can be lifted with solutions like mudjacking or polyurethane foam injection. Both use the principle of pressure from below the sunken concrete to lift it back into place, but there are some unique features, benefits, and drawbacks to each. 

Mudjacking is a more traditional method, but that isn’t really suited for use on weak or loose soils that are already struggling to support the weight of the concrete. This process involves using pressure to pump concrete slurry underneath the sunken concrete. When the slurry sets, it will hold the lifted concrete in place. However, this slurry is heavy and porous, which means it could well lead to the recurrence of sinking if the soil underneath it is too weak to bear the extra weight. This is not a permanent or effective solution in the long run. 

Polyurethane foam injection, usually through the PolyRenewal™ system, is more up to date. The two-part system uses the expansive force of the foam to lift concrete surfaces back into place and hold them there. The foam sets far more quickly than concrete, it’s lightweight, and it’s non-porous. This makes it far more useful in situations where the soil is weak or frequently saturated. This is a far better and more permanent alternative to mudjacking. 

There are other concrete lifting measures, of course, like slab piers (which work in the same way as foundation piers). Getting the right concrete lifting measure for you is all about diagnosing the underlying cause effectively. For this, you need professional intervention. 

Why Choose Foundation Recovery Systems for Concrete Lifting? 

If you have noticed damage to concrete surfaces and structures around your property, it is time to call in an expert. Luckily for you, the Foundation Recovery Systems team has been serving homeowners in Kansas City, Moberly, St. Louis, and Springfield for more than 20 years. We know what it takes to lift your concrete surfaces back into place and restore them to the best possible condition. All you need to do to get the process started is to contact us to schedule a free, no-obligation inspection and repair estimate. 

Our inspectors are highly trained to spot warning signs for all kinds of foundation and concrete damage. They will provide you with a same-day, written estimate for all costs associated with our suggested solution. You will not be pressured to book repairs during the inspection, or at any time after. However, if the situation escalates unexpectedly before you have made a decision, please do not hesitate to call us. We are always on hand to help. 

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