Concrete Lifting

The early signs of concrete settling are difficult to detect because most of it happens underground, at least in the very early stages. It’s not possible to notice the soil erosion that occurs under your Augusta-Aiken slab, both because it’s a process that takes place over a lengthy period of time and because it’s simply not possible to outright observe it because the concrete is in the way. Still, concrete settling signs appear eventually, and it’s up to you to keep an eye on your concrete structures so that you know when it’s time for repairs. If you let the settling advance too much, then you might have to replace the concrete, which is a more expensive procedure than concrete lifting.

The first sign of concrete settling is unevenness, which can easily be spotted in driveways, patios, sidewalks, and walkways. The more advanced the settling becomes, the more it will settle. A wobbly concrete step or slab is another sign of settling, even if there is no unevenness that you can visually detect. Cracks and craters are also common since concrete is more likely to break if it’s settling. This is because it’s not able to distribute weight if it’s not supported by an even base, so it cannot handle the pressure.

Look for gaps that form along the edge of the slab, right where the concrete meets the soil. If the soil next to the slab has eroded enough to form a gap, then the soil will expand in the future, and the slab will settle. This next sign is a bit more of a guess, but it can allow you to predict how much the soil under the concrete is eroding: try to notice how pitted the concrete is. Heavily pitted concrete will be more permeable than solid concrete, so moisture is able to reach the soil easily. The more eroded the soil is, the faster the concrete will settle.

The freeze-thaw effect describes the cycle water goes through as it turns into ice and then melts back into its liquid form. The freeze-thaw effect is part of the reason why it’s so important to protect your concrete from moisture exposure if you want to prevent structural damage. When water turns into ice, it expands by about 9%. It may not seem like it, but expanding ice is fully capable of displacing concrete particles. Every time there’s some sort of displacement, the concrete becomes structurally weaker with time.

The freeze-thaw cycle is capable of creating small craters both inside and along the surface of the concrete. Concrete is already impermeable, but with each new micro-tear, it allows moisture to seep through even more. As more and more water gets past the structure, the freeze-thaw cycle also displaces the soil underneath. Concrete settling advances, and then you have an uneven, structurally weak slab. The more porous concrete is, the worse its tensile strength is, so cracking is inevitable on a slab that has been exposed to moisture during the winter.

How dangerous exposure to the freeze-thaw cycle is depends on the severity of the winter climate. Although Greenville, SC, isn’t exactly a winter wonderland, there are enough nights out of the year where the temperature reaches at or below freezing for it to have an effect. Freeze-thaw is a lot more impactful on concrete with low psi, which is typically the case for slabs made for walkways, since they aren’t considered to be “heavy duty” slabs. Keeping the snow off of your concrete is an integral part of slab protection, so consider covering your concrete during the winter. This way, if your slab does settle, you can avoid having to replace it due to breakage that prevents repairs.

Concrete settling happens to every slab eventually. Settling happens because of two things outside of our control (the weather and the soil), so there’s not much we can do except protect our concrete as much as possible. The truth is, it’s impossible to tell how long it would take for a new concrete slab to settle, since the timeline depends on so many different factors. Even the concrete on your own property will not settle at the same time; your driveway slabs might settle before your patio slabs.

A big part of what causes concrete settling is the soil. In Charleston, SC, the soil is pretty sandy, so the erosion type needs to be considered. Sandy soils get displaced easily by water, so slabs that frequently get exposed to water are more likely to settle than others. This could be your driveway or your pool deck. To protect those areas, you can add a cover so that the concrete and the soil are both better protected from water.

Other outdoor slabs might also be better protected due to vegetation. If the concrete walkways you have around your yard have bushes and vegetation around them, then they might not be the first slabs to settle. Still, you should always be on the lookout for concrete settling, since it’s such an unpredictable thing. Keep in mind that if your brand new slab settles, it’s not a problem with the slab itself, and you can lift and stabilize it with a concrete lifting solution like SettleStop PolyRenewal™.

Steps can sink for quite a few different reasons, but it is typically related to the soil that they sit on in most cases. We have included a couple of the common ones below.  

• Soil Washout 

The primary and most common cause of sinking steps is uneven soil or erosion underneath the steps. As mentioned above, if water continues to flow underneath the steps, it is eroding the soil and creating voids underneath the steps, which they will slowly sink into. The extent of soil washout can vary based on a few factors, but it is not impossible to prevent.  

There are around three primary causes of soil washout. The first of these is the particular type of soil that your home is built on. The second involves the general climate and weather in your area. And the third has to do with the drainage system of your home. Obviously, you cannot change the soil type of your yard and you cannot influence the weather, but you do have control over the efficiency of the drainage system in your home. A proper drainage system can combat the other two factors and help greatly decrease soil washout.  

• Improper Base 

When your house was built, a large hole was dug to put in the foundation and an extra perimeter was dug around this area to allow for working space. When the home is finished, this extra perimeter will be back filled, which simply means that dirt is filled back into it. This dirt needs to be properly compacted down to provide a strong base, but this is not always the case. If the backfill was not compacted or soft soils were used, then it may not be a great base for concrete to be sitting on top of. So, if your steps happen to be above this improperly backfilled area, they may be more likely to start sinking into the loose soil.  

In some cases, this may mean that a more solid base or footings need to be placed under your steps. There are a couple methods that may be used either separately or together for concrete steps. It will typically begin with placing a layer of gravel to help with drainage. Secondly, a proper footing will ideally be installed. A footing is simply a foundation underneath the steps, with rebar or tubes that go down below frost level in the soil to hold for further stability.  

The concrete slabs around your Columbia property aren’t the only structures capable of settling. If you have any concrete steps around your home, then they can also settle. Just like a regular slab, concrete steps settle because the layer of soil that is meant to support them erodes and becomes uneven. Even if your steps have sunken a few inches into the ground, they can be repaired using polyurethane foam injections.

Contracts drill holes in the steps and use a handheld device to inject polyurethane foam. The foam expands and fills the void until there is enough to lift the steps back to their original position. The holes are covered back up, and the polyurethane foam is left to cure for 15 to 30 minutes. Concrete steps that have been cracked can still be repaired with this method, but only if the cracks are minimal. If the steps are significantly broken, then there is a chance you might have to replace them instead.

The only way to properly repair concrete steps is to use polyurethane foam injections. Many DIY blogs will recommend various methods that have nothing to do with solving the actual problem at hand, which is to give the steps a new support since the soil has eroded. Evening out the steps using cement, digging a hole and placing a rock under the steps, and other strange methods will only weaken the structure further and cause the steps to break completely. Without proper support, the steps will remain structurally unsound, which is extremely dangerous for all of those who use the steps. To avoid injuries, you must hire professionals for a proper concrete lifting job.