Why Does Concrete Sink?

There are typically three things that may happen to the soil underneath your concrete that can cause concrete slab sinking.

Soil Washout

Water is great at finding its way into places it’s not supposed to be. Even if there’s the tiniest leak in a concrete surface, water from the rain, plumbing leaks and even just condensation can make its way underneath that surface.

Over time, this water will start to wash away the soil piece by piece. This typically doesn’t happen overnight unless there’s an extreme weather or plumbing condition. However, no matter how slowly it erodes, you’ll start to notice at some point.

Eventually, there will be less soil underneath the concrete supporting it. As the amount of soil diminishes, the slab will start to sink into the empty space underneath. That’s why you’ll start to see concrete slab sinking.

Poorly Compacted Soil 

During construction, the construction crew pours the concrete over the soil. To prepare the ground for the concrete, the crew needs to pack the soil down tightly. This forms a good base for the soil to hold onto and stay stable on.

However, if the crew didn’t compact the soil tightly enough, it can start to compress because of the weight on top of it. The concrete is essentially sinking because of its own weight and any weight you’ve placed on it.

This is especially dangerous if it’s happening in your basement. A sinking basement floor typically signifies that there’s something wrong with your home’s foundation, and that can lead to many problems throughout your home.

Moisture Content Changes

The weather moves through cycles of wet and dry naturally. It’s normal for soil to be wetter, then drier, and to repeat that process. Unfortunately, while it’s natural, it’s not great for the concrete resting on top of it.

When soil absorbs moisture, it becomes bigger. When it dries out, it becomes smaller. This expanding and contracting process exerts pressure on the concrete above it, and that can lead to sunken concrete over time.

This can be especially obvious if the concrete is on a type of soil that expands or contracts more significantly than other types of moisture. It should rest on a more solid type of soil if you want to make sure it lasts a long time.

It’s easy to see why issues like mold and foundation cracks need immediate intervention, but some homeowners can be confused regarding why they need to fix sunken concrete. If it’s just an aesthetic problem, why invest money into fixing it?

The reality is, it’s not just an aesthetic problem. This is how sinking concrete can impact your home in three of the most common places to find concrete.

On Your Patio 

If you have a patio that rests on the soil, chances are you’ve poured some kind of concrete on it. That might be a significant amount of the area, small pieces of the lawn, or a walkway leading up to the door.

The thing is, you probably walk on that concrete every day. Concrete patio sinking can lead to trips and falls as the different pieces of concrete slowly become more out of place with each other. The last thing you want is for someone to take an unexpected spill while carrying something important.

Additionally, entropy happens very slowly, and there’s no real way to know when something’s going to break. If a thin layer of sunken concrete gets to a specific point, you may find that one day, stepping on it causes it to crack pretty dramatically underneath your feet.

In Your Garage and Driveway

Sunken concrete can also cause problems in the garage and driveway. That’s because it’s traditionally able to withstand a lot of weight, especially if it’s poured more thickly. However, problems can arise when it starts sinking.

Although your car’s tires can probably handle a limited amount of bumps, they’re not meant to drive over cracks and sharp bumps every day. Even the small bumps that the unaligned concrete can create may cause tire issues.

The sunken concrete may also have sharp edges. If your car drives into a piece of sunken concrete with abnormally sharp edges that stick out just a little too much, you can end up with an unexpected flat tire.

In Your Basement 

If your crawl space or basement doesn’t have an exposed dirt floor, it likely has a concrete floor. Older homes may have stone foundations, but most modern homes have concrete foundations because they’re less prone to cracking.

However, if you’re starting to see a sinking basement floor, that can indicate trouble. It may mean that your actual foundation is having issues. Homes set up for foundation trouble can have problems strewn throughout the entire structure.

If you don’t fix a sinking basement floor, you’re opening yourself up to other problems that foundation issues tend to cause. In the worst-case scenario, home walls may even end up falling down if you don’t fix these foundation problems.

What can you do to fix these problems? Sinking concrete can be concerning, but many homeowners don’t take action because they aren’t even sure what a professional would be able to do for sinking concrete repair.

There are a few things an expert can do to help bolster your sinking concrete. They have various levels of success.

Replacement

In some situations, the only fix may be to fully replace the concrete. This might happen if the concrete already has extensive cracks and breaks, or if the soil underneath was so poorly prepared that there’s no way for the concrete to retain its shape.

This typically isn’t the first thing an expert will recommend. Not only is it unwieldy and expensive, but it also may not address the actual problem. The problem might come back, depending on the reason for it.

If a JES expert believes that replacement is the only way to fix your sunken concrete, they’ll let you know. However, typically, there are more cost-efficient and labor-efficient options when it comes to sinking concrete repair.

Pressure Grouting

This option, also called “mudjacking,” is an old-fashioned method of concrete leveling. Essentially, pressure grouting requires drilling soda can-sized holes across the concrete slab, then pumping in cement grout and waiting for it to dry.

Although this was the preferred option for a long time, it’s falling out of use as more accessible options come into play. Pressure grouting is very invasive, and it can take several days for it to cure, during which you can’t walk or drive on the concrete surface.

Many professionals no longer use pressure grouting because of its inefficient nature. If you draw on the expertise of a JES professional, you’ll be able to find a better solution that will more effectively meet your needs.

Polyurethane Foam Injection

With a polyurethane foam injection, an expert will drill a few penny-sized holes into the concrete, then inject a polyurethane mixture into it. The mixture will dry in roughly 15 minutes, and it can even seal the slabs from future water damage.

This is the preferred JES method because it’s non-invasive, quick to cure and lightweight. No matter what surface you’re leveling, a polyurethane foam injection may be able to bring it back up to its previous levels.

When you request a free inspection from JES, a JES professional will let you know whether your sunken concrete may be able to benefit from a polyurethane foam injection. This is typically the most effective solution for sunken concrete.

If you’re worried about spending the money necessary to truly fix your sunken concrete problems, you may be wondering why you need to fix it now. After all, why fix something if it’s not actively causing you problems?

There are a lot of reasons to perform home repairs before they become unmanageable. Performing sinking concrete repair early will provide a host of benefits.

No Replacement Required

If your sunken concrete gets to a point where it has substantial cracks throughout, you might not be able to use polyurethane foam injections to re-level it. Even if you don’t see the cracks, they might show up upon leveling.

At this point, the only option might be to completely replace the concrete. Replacement can be extremely expensive, very time-consuming and annoyingly invasive. It’s cheaper and easier to just fix it now.

When you contact a JES expert to perform a free inspection, you’ll be able to learn whether your sunken concrete can still benefit from polyurethane foam injections. If you get in contact early, it almost certainly can.

No Tripping or Balance Concerns 

You might not have tripped on your sinking concrete yet, but what’s going to happen as it continues to sink? Even if you don’t have existing tripping or balance problems, you never know what’s going to happen if your shoe catches on an unfortunate edge.

This is also a big problem for individuals with balance-related issues, including people who use canes or walkers and people with poor balance. You probably want to make sure your home is an inviting place, and that’s a problem you need to address.

It’s better to deal with this problem before you trip and break something. A JES expert can help you level your sunken concrete back to the place where it used to be. That’ll help you ease your fears regarding the potential for tripping.

Avoiding Structural Issues

If you have a sinking basement floor, you’re at high risk for foundation problems. Whether you’ve noticed foundation issues or not, you need to make sure you’re not leaving those problems until it’s much too late to fix it.

Tackling these problems as early as possible will make sure that your foundation stays intact throughout the years. If there are any problems, it’s much easier to handle those problems if you find them very early.

It’s tough to know whether you have foundation problems without an inspection. You can schedule a free inspection through JES today, which will make it easier to determine exactly what problems you’re facing and how you can fix them.