As homeowners, we’d all love it if our driveways would remain slick, flat, and even forever. However, this is impossible because of the way soil works. As soil gets wet and dries out, it changes its ability to support concrete slabs.
Slight unevenness to a driveway may seem like a minor issue, but it should be solved quickly. The situation will get worse over time and the cost to fix it will rise. The solution to uneven driveways is concrete lifting, but there is much that needs to be understood about the different lifting methods before you grab a phone and contact an expert.
Choosing the best method for your driveway will save you a big headache down the line. Here are the best concrete lifting solutions and how they can improve your driveway.
Solutions for Uneven Driveways
Many homeowners don’t give much thought to the uneven concrete slabs of their driveways. Many only use their driveways as an entryway to their garage. When driving a car, uneven pavement isn’t a very big obstacle. It’s not even all that noticeable, especially for those who drive big cars.
However, driving over uneven concrete may eventually cause damage to the slabs, your car, and even your property. The cracks or uneven slabs will only get more pronounced when they’re put under the strain of a heavy car. Eventually, they can leave fissures that wear down your tires, and raised slabs can harm the undercarriage of your vehicle. They can even increase the chances of tripping and falling for small children, the elderly, or people with disabilities.
As such, uneven driveways need to be looked into. Concrete settling only gets worse with time and the pavement’s functionality is heavily affected. Mild settling can lead to severe cracks and breakage that will force you to replace the entire driveway. Before that happens, here are the solutions you can take to repair uneven concrete driveways.
Mudjacking or Slabjacking
Mudjacking (also called slabjacking) is the oldest form of concrete lifting there is. Contractors drill holes in the sunken pavement and pump in a mixture of cement, sand, and mud. The mixture then fills the void between the sunken soil and the concrete slab, until there’s enough substance to lift the concrete and level it with the rest of the pavement. The holes are then filled and covered up in such a way that the concrete slab looks untampered with.
It depends on how much work needs to be done, but the whole procedure can take a few hours to a few days. After it’s all done, the cement mixture needs some time to harden, so it’ll be a while before you can drive in and out of your driveway.
- Is Mudjacking the Right Method for You?
There are a lot of downsides to choosing mudjacking as a concrete leveling solution. Mudjacking is an old, traditional form of concrete lifting, that actually is quite expensive, invasive, and not effective.
Driveways sink because of soil shrinkage and compaction, which creates a hole between the soil and the concrete slab. Unable to adequately provide support, the concrete slab sinks and settles into the soil. Further soil compression only makes shrinkage worse because the soil gets pushed down further. Compaction can happen naturally, but it can also be caused by mudjacking.
The mixture that’s created to fill the hole is extremely heavy. Once it dries, it presses down on the soil and creates pressure. Over time, this pressure further compacts the soil and causes concrete settling all over again. Depending on how much pressure is placed on the soil, the concrete can sink even more than it did before the mudjacking job.
Obviously, this is not ideal, and it’s a consequence of the mudjacking method. There’s no way around it because the slurry’s primary ingredient is cement. If the contractors don’t add enough cement, the slurry won’t be firm enough to support the concrete. However, more cement makes the slurry thick and heavy.
There’s not much contractors can do to make the cement mixture lighter, which is why mudjacking is a solution that only lasts five to 10 years at best. The mixture is also partially made of mud, which eventually washes away. The driveway would need to get lifted multiple times over the span of a few decades until the concrete’s structure fails due to the constant rework. Don’t let this information discourage you from lifting your driveway. There is another, more modern method of concrete lifting that is a permanent solution to concrete settling.
Using polyurethane foam for concrete lifting is the modern solution to uneven driveways. By and large, it’s a much better method than mudjacking. Like mudjacking, the contractors drill multiple holes in the concrete. They then inject a polyurethane solution into the hole. The polyurethane foam expands and lifts the concrete slab until it’s leveled with the other slabs.
The holes drilled for polyurethane injections are a lot smaller than those drilled for mudjacking, so the procedure is much less invasive. When it’s time to fill them and cover them up, the pavement looks brand new.
- Are Polyurethane Injections the Right Method for You?
There are only two downsides to using polyurethane injections for driveway leveling: Not all contractors offer this method. While it may seem like more of an initial investment, it is a worthwhile one because the results will last a lifetime.
Polyurethane foam is a lot lighter than the cement mixture used for mudjacking. It doesn’t put any pressure on the soil underneath and prevents further soil compaction. You might be wondering how a material so light can hold up heavy concrete, but the polyurethane used for driveway leveling is very different from the polyurethane used for making dishwashing sponges.
The soft, malleable polyurethane foam used to make sponges is known as open-cell polyurethane. Closed-cell polyurethane is a lot firmer because the cells are sealed together. It’s tough enough to support concrete (as well as other added weight), while still alleviating the soil of pressure.
One of the biggest issues with mudjacking is that the cement mixture is too rough to properly fill the gap under the concrete. Since the hole isn’t properly filled, concrete sinking is still a possibility even after the driveway is repaired with mudjacking. This doesn’t happen with polyurethane injections. The expansive, pliable nature of the foam also means that the polyurethane will fill the holes completely. It’s a big part of why the polyurethane foam method is a lifelong solution.
Once the procedure is done, you can use your driveway as you usually would in less than an hour, depending on the scale of the job. It’s fast, convenient, and a much better solution to concrete sinking. Take the time to look for a local contractor that uses polyurethane injections to save yourself from future problems with your driveway’s structure.
Why You Shouldn’t Try to Level Your Driveway Yourself
Many problems a homeowner faces are things they can fix themselves. Driveway leveling is not one of them. It may seem like a smart, frugal idea to try a DIY method to level a driveway, but it’ll end up costing you more in the future.
DIY methods are, more often than not, bandages that temporarily fix surface-level issues. There’s a lot more to construction than one would think, and if you don’t know how it all works, whatever method you use won’t work.
- DIYs Will Not Fix the Problem
There are many DIY methods out there that claim to fix uneven driveways. These methods will never work as well as proper driveway leveling methods like polyurethane injections for multiple reasons. The biggest reason is that they do nothing to slow down soil shrinkage.
A lot of the solutions you find online recommend sand, mud, and gravel to fill the gap between the concrete and soil. These materials are not good foundations for a concrete slab. Mud and sand wash away after a few years, and gravel is too loose, so it easily shifts around.
North Carolina may not get many strong earthquakes, but it is part of the Eastern Tennessee Seismic Zone, so it gets multiple (albeit small) earthquakes a month. If the foundation isn’t dense enough, it will come loose. Settling occurs shortly after, and then you’re back to square one.
Not to mention, concrete slabs are a lot heavier than people think, some weighing more than 600 pounds. Driveway leveling is not a one-man job, so you would need to find multiple people who have the finesse to handle the slab without breaking it or getting themselves injured.
Polyurethane foam spray can be bought at a store, so you might be tempted to level the concrete yourself by replicating professional concrete lifting methods. You would have to drill multiple holes in the concrete, and they’d need to be big enough to allow the polyurethane foam through. You would also need to pump the foam properly, so it doesn’t block the holes. All in all, it’s easier and less time-consuming to call a contractor with the team and tools to do the job properly.
Uneven Driveway: Problem Signs
Being able to tell when your driveway is settling is extremely important. By tackling the issue while the damage is minor, you can save money as well as prevent injuries due to the uneven pavement. Here’s what to look out for in a driveway that’s settling:
- Large Cracks
Large cracks are a good indicator of settling concrete. They usually occur in the middle of the pavement. When multiple cracks appear and form segmented squares, it’s known as “crocodile cracking.” Cracks allow water to seep through the concrete easier. This speeds up the swell-shrink process that causes settling.
- Uneven Concrete
If your concrete looks slightly uneven, it’s starting to shrink. Concrete slabs that weren’t made correctly or have poorly compacted foundations tend to settle very shortly after being created. But if you notice your driveway isn’t as flat as it used to be, observe each slab to determine where the settling is happening and then call a contractor
Most common around the edges of concrete slabs, breakage is another indicator of settling. The edges of the slabs are a lot weaker, so they aren’t able to support as much weight as the rest of the concrete. They tend to crack, then break off when settling onto the sunken soil.
Uneven concrete is all about the soil that’s used as a foundation. When it gives way or shrinks and loses its topsoil volume, a void remains and there’s nothing supporting the concrete. This is something that cannot be prevented, and very little can be done in the face of earthquakes and floods, but certain measures can be taken in order to prevent soil erosion and shrinkage.
- The Kind of Soil
The type of soil used as the foundation for the driveway impacts how severe and how quickly the settling is. Soils with big, grainy particles tend to wash away because water is able to pass through easily. It’s the kind of soil that doesn’t compact well, so it’s loose and shifty. It’s vulnerable to floods, snow, rain, and earthquakes.
Expansive soils (often clay soils) compact well, so they are denser and make for a much better foundation. However, because of the clay content in the soil, expansion occurs at a higher rate. The more the soil is able to expand, the more it’s able to shrink. Despite its swell-shrink capacity, contractors still use clay soils because it compacts easily. This makes it easier to manipulate and saves time when laying down the foundation.
- Soil Shrinkage
Soil shrinkage occurs when the moisture in soil dries out. As the moisture leaves the soil, the individual particles come together since there is nothing between them anymore. The soil becomes denser, but due to shrinkage, it loses surface volume.
Once the soil loses surface volume, there is nothing supporting the concrete. With the added weight of cars, snow, and people walking on the driveway, the concrete gives way and settles on the soil. Soil shrinkage is a naturally occurring process that can’t be controlled or predicted, but placing a canopy over the driveway will limit the concrete’s exposure to the elements and mitigate the damage done by soil shrinkage.
When faced with an uneven driveway, a homeowner’s first thought is that there’s something wrong with their concrete. Most of the time, however, the concrete is not the problem. Settling is caused by the soil under the concrete slab, so replacing the slab is completely unnecessary.
- What Needs to Be Fixed
When wanting to fix uneven concrete, the focus shouldn’t be on the slab itself just because it’s the most apparent part of the problem. Replacing your driveway’s concrete is a much more expensive option than calling a contractor that can use polyurethane injections. You would have to wait for the concrete to fully harden once it’s poured in, and the whole thing can take a few days.
New layers of soil will have to be placed down anyway, so it’s more sensible to simply fill the gap caused by soil shrinkage. If you still think that the concrete is too broken and cracked, call a contractor about it to get an expert opinion. There’s still a chance the original concrete can be saved without having to spend an arm and a leg getting a new slab.
- Replacing the Soil Won’t Work Either
Hearing that the clay soil is the true culprit of concrete settling, you might be wondering if you should also replace the soil before lifting the concrete. However, North Carolina’s state soil is one of the best foundation soils used in construction, called Cecil soil. The reason it’s so good is that it has brown-colored loam topsoil, which has very little clay content but is still firm and perfect for foundation use. Underneath the loam is red-colored clay soil that condenses well and offers great support.
Even Cecil soil will shrink over the course of a few years. Besides, replacing the soil located where the driveway settled doesn’t change the fact that the rest of the driveway will eventually sink. To fully replace the soil, you would have to alter the entire driveway. This is a much more invasive process than polyurethane injections.
Just how much damage can settling do? As it turns out, it can do a lot. The biggest incentive toward fixing uneven concrete as soon as you notice early problem signs is the preservation of your concrete slabs. The longer you wait to lift your driveway’s slabs, the more likely it is that you’ll have to replace them.
- Settling and Breakage
Uneven concrete slabs will break over time. The way they break depends on the size of the slab, where the soil shrinkage occurs, and how much weight the settled concrete has to withstand. Settling is most likely to happen at the edges of the concrete slab. This is because most driveways end where the front yard begins and most front yards have plenty of grass and soil. The front yard absorbs a lot of water, which spreads to the soil under the driveway.
Because the edges are the weakest part of the slab, they are more likely to break off, especially if the slab is very large. Driveway slabs are especially at risk of breaking because of heavy cars. Most cars weigh about 4,000 pounds, which is a lot of weight to put on a slab with poor support.
- Preventing Breakage
There are a few things that can be done to prevent your driveway’s concrete from breaking. You’ll want to try prevention methods because broken concrete can be very difficult to repair, especially if it’s a piece off the edge. Cracks and breakage in the middle of the concrete can be patched up, but the cracks still allow water to seep through.
If you’re able to, avoid driving on the sunken slab or try to drive in such a way that only a small part is driven on. If you’re unable to cover the entire driveway, try to cover the slab that settled, at least until it’s time to lift it. Limiting the amount of moisture the slab is exposed to will prevent further settling and breaking.
Who Should I Call for Driveway Leveling?
Now that you understand the different concrete lifting methods, it’s time for you to make a choice. If the vast majority of your driveway is uneven and a big job needs to be done, you might immediately try to go for the mudjacking solution. However, many contractors offer free inspections, so it wouldn’t hurt to speak to a contractor who works with polyurethane injections. After all, it is the superior solution.
Polyurethane is a newer method, so not many companies offer it. Many only use this method for commercial structures and corporate clients, which not only makes it more expensive but also makes it hard to find an expert who knows how to use this method in residential properties.
However, there are a lot of contractors dedicated to making polyurethane injections an affordable solution to uneven concrete. The good news is, you won’t have to look very far to find the right experts that can help you.
Call Tar Heel Basement Systems If You Have an Uneven Driveway
Tar Heel Basement Systems is a company that serves homeowners in Raleigh and Winston-Salem, NC. Founded in 2003, we’ve been providing groundbreaking, accessible, and affordable solutions for concrete lifting for many years. Contact us today to schedule a free inspection and repair quote! You can trust the experts at Tar Heel Basement Systems to always be there to help. So don’t hesitate to call us if you need your driveway lifted and looking as even as ever.