Concrete Lifting

It is impossible to prevent concrete deterioration. All concrete experiences some sort of damage over time, especially in areas where it is frequently exposed to water, like a foundation, driveway, or pool deck. As a matter of fact, even when it’s only a few days old, concrete still develops micro-tears because of the material it’s made from. 

Given the fact that soil shrinkage and displacement is also inevitable, you shouldn’t be surprised if your concrete slab settles and breaks. Is there any way to avoid this?  

• Soil 

When soil shrinks and compacts, the particles become displaced and loosen up. As the soil disperses, it’s no longer able to support the slab. When the slab is put under pressure, more than it can withstand, it breaks apart and settles against the displaced soil. 

Soil displacement is inevitable, but there are things you can do to discourage it. Grand Junction’s soil is incredibly dry, but it’s coarse and sandy. This means that soil expansion and shrinkage is not common, but displacement due to erosion is likely. Having proper yard drainage and making sure your soil stays as dry as possible can help deter this natural process.  

• Concrete 

Making sure your concrete is structurally sound is the best way to avoid cracks and breakage. If there is soil erosion, you can prevent your slab from breaking by limiting exposure to weakening substances. Protect your concrete from water, snow, and salts to make sure it doesn’t slowly deteriorate. 

Driveways, patios, and pool decks should be covered to limit climate exposure. You should also avoid placing heavy objects on the concrete, and if you must, make sure the weight is distributed as evenly as possible. This means that cars should be parked in the middle of the driveway and no heavy furniture should be placed on one side of the patio. 

In short: the answer depends on whether or not the concrete has already been poured and cured.  

• During the Production Process 

If a new house that you’ll move into is being built, there is one thing you can do to strengthen the concrete slabs on the property. Adding steel rods, or rebar, is the best way to increase the tensile limits of concrete. Rebar has excellent tensile distribution and can bend a lot before snapping in half. By adding rebar through the concrete, whenever the slab has to withstand pressure, the energy gets released and distributed through the slab, but a lot of the tensile load is handled by the rebar itself. With rebar, concrete slabs are less likely to break from tensile pressure. 

There is no material that can be mixed into the concrete in order to reinforce it. Concrete needs to be firm enough to withstand a large amount of weight. If you add anything that makes it more elastic, you run the risk of weakening its compression properties. Making structurally sound concrete is all about mixing the right amount of the right materials. Experimenting with different materials might actually be more detrimental to the health of the slab.  

• After the Curing Process 

Once concrete has been poured and cured, there’s nothing you can do to strengthen it. Concrete slabs strengthen on their own over time. For a small slab, it can take about a month to fully finish strengthening while large slabs can take up to a year. You may have heard that pouring water on the slab will strengthen it, but this is only true if the slab is in the curing process, not after. 

If you have a slab that has cracked and settled due to pressure, there is a way to fix it and reinforce it so that it doesn’t break again. It can be lifted using polyurethane foam, which is the best material to lift settled concrete slabs. The foam creates an even foundation for the slab to rest on, so that even when pressure is applied, it doesn’t break. 

When looking at the deterioration the slabs around your home experience, you might notice that your slabs are not reinforced with rebar. Typically, concrete slabs used for walkways, driveways, pool decks, and other areas of your home are only four inches tall and are not reinforced. 

If your concrete is sinking, then you might be wondering if you should replace your settled slab with one that has rebar. Unfortunately, rebar does not stop a concrete slab from settling. Replacing and repouring a brand-new slab is a lot more expensive than simply leveling it. It’s also a waste of time because you’ll be dealing with the same settling issues in a few years despite the addition of rebar.  

• What It Does 

Rebar is used to reinforce concrete because it has great compression strength but poor tensile strength. Compression strength means that concrete does not lose despite supporting a lot of weight. Tensile strength measures a material’s ability to resist breaking under pressure. Poor tensile strength is the reason concrete breaks so easily when hit with a hammer: Because the pressure is concentrated in one spot, the concrete cannot take the hit and breaks in half. 

Rebar is meant to increase concrete’s tensile strength by absorbing pressure. The rebar redistributes pressure evenly throughout the slab so that it’s not concentrated on one point. This way, the concrete can take on heavier loads and withstand a lot more.  

• What It Doesn’t Do 

The reason rebar does not help in preventing concrete settling is because settling has nothing to do with a slab’s tensile strength. Regardless of how much pressure it’s able to withstand, if it doesn’t have a solid foundation, it will sink. Therefore, it’s futile to try to add rebar to the slabs around your house just to avoid settling. If there’s soil displacement, there will be settling. 

What rebar can help with is concrete cracks after there has been settling. If the slab has settled, then there’s a chance it will break apart because it cannot distribute pressure properly on an uneven base. Rebar can help the slab stay strong and not crack. Still, adding reinforced concrete to your home’s pavement is not worth it when you can just use polyurethane foam injections. 

Whether you live in a new home or an old one, you might want to know how soon it will be until one of your slabs settle. The truth is, it’s difficult to tell how much the soil will shift about until it leads to concrete settling. Part of what’s so difficult about it is the fact that the soil remains underground where you cannot see it very easily. 

Still, there are certain events that accelerate the settling process. If you’re able to recognize these factors, then you might be able to prevent settling.  

The Concrete 

Something you should factor in when trying to tell when your concrete will settle is the concrete slab itself. The age of the concrete plays a significant role in settling because the stronger the concrete is, the less likely it is to settle. Over time, all concrete begins to crack no matter how much you take care of it. These cracks make it easier for water to reach the soil and displace it. The way the concrete was mixed also plays a part since certain materials used for the mixture will have an effect on the concrete’s psi (pound per square inch), which in turn will affect how the slab reacts to the loss of soil. 

If the concrete isn’t strong enough it will settle considerably. After settling, weak concrete is more likely to break apart because it cannot handle any pressure. As a homeowner, you need to be extra vigilant about concrete settling if you live in an older home. If you’re not careful, then the slab can break apart to the point where it cannot be repaired.  

Other Things to Consider 

Other things you should consider are the external factors that accelerate concrete settling. Having an uncovered driveway will increase your chances of seeing settling around your home. Above-ground pools can often erode nearby soil as well because of all the splashing and spilling, especially if you have children. 

Your sidewalk is more likely to settle first before your actual driveway simply because it is used more. Daily usage contributes to settling, so even something seemingly insignificant as people walking on the sidewalk does have an impact if the concrete is already failing. While the slab is stable, it will be able to support excessive use. However, once the soil begins to loosen up, every step brings the slab closer to settling. 

Knowing what concrete lifting method you need for your driveway or sidewalk is just as important as knowing that you need it in the first place. The two main repair methods experts may recommend are mudjacking and polyurethane foam injections. Mudjacking is the old-fashioned way of lifting a slab. It’s highly inconvenient and doesn’t last exceptionally long because it relies on a cement mixture to even out the slab. Cement can make settling worse because of its rough texture and weight. 

A much better solution would be a polyurethane foam solution, like PolyRenewal™. Unlike mudjacking, PolyRenewal™ doesn’t only focus on lifting the concrete. It effectively solves the settling problem by using a material that is guaranteed to put a stop to soil erosion. 

What Are PolyRenewal™ Foam Injections?  

PolyRenewal™ is a modern solution to the concrete settling problem. It’s an innovative method that uses polyurethane foam to lift and stabilize sunken concrete. If you hear the words “polyurethane foam”, then you might think about a soft material used to make sponges. The material used for concrete lifting is closed-cell polyurethane, which is denser than the open-cell polyurethane you’re probably thinking of. Closed-cell polyurethane foam is incredibly strong and is capable of lifting concrete over thousands of pounds. 

Still, it’s light enough that it doesn’t put any pressure on the soil under the slab. This is important since heavy weight causes even more soil displacement. Polyurethane foam is also impermeable, so it blocks water from seeping through to the soil and further eroding it. Because it’s waterproof, it doesn’t erode with time since water cannot solute the molecules and displace them. The same cannot be said for the cement used for mudjacking.  

How Is PolyRenewal™ Installed? 

Part of what makes PolyRenewal™ so great for concrete lifting is how easy the entire process is. Small holes the size of a penny are drilled into the slab. The polyurethane foam is injected through these holes and it expands until it fills the void and lifts the concrete. The holes drilled are then covered up, and because they are so small, your concrete looks untampered with by the time it’s all done. Depending on the size of the job, concrete lifting with PolyRenewal™ can take between a few hours to a day. 

After the foam is injected, it takes 15 to cure, after which the concrete slab can be used as normal. With mudjacking, it takes 24 to 48 hours, which can be inconvenient. A quick curing time is incredibly important if you must repair your sidewalk as well. If you live in a heavily populated neighborhood, then pedestrians can step on a recently repaired slab and weaken the lifting material. By using polyurethane foam, you can be at peace no more than 30 minutes after the job is done knowing that your slab can finally be used normally. 

There are two main methods of concrete lifting used today: mudjacking and polyurethane foam injections. Polyurethane foam has many advantages over mudjacking. It lasts longer and the material not only discourages further settling, but it also discourages tensile pressure.  

• Mudjacking 

Mudjacking involves pumping a cement slurry underneath a settled concrete slab until it lifts it up. The cement then hardens and supports the slab after a few hours. With mudjacking, the cement slurry has a rough texture that has the potential to create complications for the slab. The slurry is so rough and heavy that it’s not able to evenly distribute itself underneath the concrete and many gaps are left. Because there are gaps, it creates an uneven foundation that affects the way the slab reacts to tension. With mudjacking, there’s always a risk that the slab will be unable to withstand pressure and cracks again. 

Cement is also very heavy, so it compresses the soil below. Soil compression is responsible for concrete settling, so you definitely don’t want to set the soil under a material that will only make things worse. Like the slab above it, the cement slurry is also permeable, so water can get through it, reach the soil, and cause more settling.  

• Polyurethane Foam 

Polyurethane foam injections are similar to mudjacking, except instead of a cement slurry, polyurethane foam is used to fill the gap under the slab. It’s light enough to not press down on the soil underneath it, effectively reducing soil compression. It’s also impermeable, meaning that no moisture will make its way through to the soil. Polyurethane foam is initially very soft as it’s distributed under the slab. It expands and is able to fill the gap under the concrete completely. 

Because it leaves no gaps, when the slab experiences pressure, it is less likely to crack because the tension is distributed evenly. This is because the slab is being supported by an even foundation, the foam, leaving no room for the pressure to overwhelm a specific part of the slab.