Comparing Concrete Leveling Methods

Over time, concrete can become uneven when the subgrade beneath the slab loosens or shifts, leaving it unsupported. The slab may loosen or shift for several reasons, including soil erosion, poor compaction during initial installation, freeze-thaw cycles, tree roots, heavy vehicle use, and more.

When concrete becomes uneven, you need to fix it wherever it is because it’s a safety hazard. The longer you let problems fester, the more expensive the fix will likely be.

In most cases, uneven areas on a slab can be fixed via concrete leveling, a cost-effective alternative to a replacement. There are four primary ways to level concrete: polyjacking, mudjacking, slurrying, and self-leveling concrete.

Polyjacking

Also known as “foam jacking” or “concrete lifting,” this minimally invasive method involves drilling small holes into the concrete slab, then injecting liquid polyurethane so it reaches beneath the slab. The liquid expands into a high-density foam that fills voids in the soil and gently lifts the concrete to its proper level. To finish the process, the holes are filled, and the concrete is generally safe to walk on again after about an hour of cure time.

Benefits

• It’s a minimally invasive and effective method.
• It’s fast-acting; the foam dries in about an hour.
• It’s long-lasting. The polymer foam won’t degrade or wash away over time.

Disadvantages

• Polyjacking typically costs more than other methods, but it’s still up to 1/3 of the cost of a full replacement.
• Foam expansion can be difficult to control, so it’s important to work with a credible contractor.

Best Use Cases

Like all concrete leveling methods, the primary use case is for lifting or stabilizing sunken concrete that remains in good condition, but it can be particularly advantageous in situations where:

• The soil is weak, soft, or poorly compacted (especially clay soil and sandy soils common in Michigan) because the injected foam adds less load than other methods.
• There are underlying water and erosion issues because polyurethane is waterproof and won’t wash out, shrink, or soften.
• When time is of the essence, such as in commercial or industrial applications like loading docks or warehouse floors where downtime needs to be minimal.
• Decorative concrete, since the injection holes are relatively small compared to mudjacking.
• Interior leveling, since it’s a cleaner process.

Mudjacking

Mudjacking is the traditional leveling method. The process involves drilling larger holes and pumping a slurry, usually a mix of water, sand, soil, and cement, beneath uneven areas. The concrete lifts as the slurry fills the space.

Benefits

• It is more cost-effective than other leveling methods.
• It uses natural, sustainable materials.

Disadvantages

• It’s not as fast-acting as polyjacking.
• It’s more invasive and requires larger drill holes.
• The slurry’s weight can add load to the subgrade.

Best Use Cases

Mudjacking may be better than polyjacking and stonejacking when the voids causing uneven concrete are larger, the subgrade is already stable and can handle extra weight, and traditional slabs (non-decorative) allow a few patched holes.

Stonejacking/Limestone Leveling

Limestone slurry jacking, sometimes called stonejacking or limestone leveling, works similarly to polyjacking and mudjacking because it involves drilling holes into the concrete. The difference is in the material used to fill the voids. In stonejacking, the lifting material consists of water and limestone.

Benefits

• It shrinks less than traditional mudjacking.
• It’s made from natural, sustainable materials.

Disadvantages

• Drilled holes are usually larger than those used in polyjacking.
• Like mudjacking, stonejacking adds weight to the subgrade.

Best Use Cases

Limestone leveling works well for heavy or large-scale concrete leveling jobs that need maximum support and better void filling.

Self-Leveling

Self-leveling is a modified cement mixture that flows like a liquid and creates a level surface once applied. Unlike other concrete leveling methods in this article, it isn’t invasive. Instead, you apply it on top of the concrete, where it smooths out to correct surface variations. It’s best for leveling a concrete underlayment so you can apply flooring or another material on top.

Benefits

• It quickly and easily fills in minor dips or irregularities in the concrete surface.
• It dries quickly, usually within 1-2 hours.
• It’s strong and resists cracks and breakage.

Disadvantages

• It’s not suitable for most concrete applications; it works best as a prep underlayment or as a finisher on a floor topping.
• It has a limited thickness range.
• It dries quickly, which is also a disadvantage. In most cases, workers have only 10-20 minutes to place the mix correctly before it begins to cure.

Best Use Cases

You can’t use self-leveling concrete to fix uneven areas of a concrete slab. Its primary use case is for preparing an underlayment before finished flooring is installed.

Schedule an Inspection Today

If your concrete is uneven, contact Detroit Concrete Leveling today for a free inspection. Our team can help you determine whether concrete leveling is the right solution for you based on the condition of your existing concrete, and which method, polyjacking or limestone leveling, will be most effective.