Mudjacking and polyurethane injection are common concrete leveling repair techniques, but do they actually work?
Concrete lifting and leveling solutions are popular repair methods for sunken concrete slabs. If this is your first time dealing with a concrete issue like this, it may also be the first time you’ve heard of concrete lifting or leveling solutions and you may be skeptical about whether it really works.
Yes — concrete leveling works, and it has a long enough track record to prove it. Lifting a settled slab back to grade by injecting material underneath is a standard repair, used on everything from residential driveways to airport runways. The two methods you will see quoted are mud jacking, which uses a cement slurry, and polyurethane concrete leveling, which uses expanding foam. Both raise concrete. They differ in weight, cure time, hole size and how long the result lasts. Concrete lifting and leveling, slab leveling and concrete raising all describe the same category of repair.
Mud Jacking vs Polyurethane Concrete Leveling
Mud jacking is the older of the two methods. A contractor drills holes roughly two inches across, pumps a cement-and-soil slurry beneath the slab, and the slurry fills the void and pushes the slab up. Polyurethane concrete leveling does the same job with a different material. The holes are around the diameter of a pencil, the material goes in as a liquid and expands, and it weighs a fraction of what slurry weighs.
The practical differences:
Weight. Slurry is heavy. On soil that was already settling, adding weight can restart the settlement that caused the problem. Polyurethane is light enough that it does not load the ground.
Hole size. Two-inch holes stay visible after patching. Pencil-diameter holes are far less noticeable, which matters on a driveway or a finished floor.
Return to service. Slurry needs time to cure before the slab can take weight. Polyurethane sets quickly, so a driveway is usually back in use the same day.
Longevity. Slurry can wash out or erode over time. Polyurethane does not absorb water and is not broken down by soil chemistry.
Mud jacking is not a bad repair, and it is often cheaper up front. Where it struggles is on weak soil, in visible locations, and on jobs that cannot afford downtime.
Driveway Leveling
Driveway leveling is the most common residential application and the easiest case to judge for yourself. If one slab has dropped below its neighbor and you can feel the lip underfoot or hear it as you drive over, the slab has settled and the soil beneath it has moved.
A driveway leveling job is usually a matter of hours. The contractor drills a small pattern of holes, injects polyurethane until the slab returns to grade, patches the holes, and the driveway is back in use. Replacement, by comparison, means demolition, disposal, new concrete and a cure period measured in days before anything can drive on it.
The repair holds for as long as the soil beneath stays stable. Polyurethane also seals the void it fills, which stops water washing more soil out — one reason a levelled driveway often outlasts the settlement that caused it.
Mud Jacking
Mudjacking is the process of lifting concrete slabs by injecting a mixture of mud, sand, cement, and similar materials beneath the slab. The mixture is injected through a series of small holes in the affected slab. The holes used for mudjacking are slightly larger than the holes used for polyurethane injection. The mudjacking solution fills the voids beneath the slab and compacts soils. Enough material is injected beneath the slab to lift it back to its appropriate grade and then the holes are patched.
It is a time tested and inexpensive solution to concrete repair, but it does have some negatives to consider. The material used in this process is very dense and can cause a new round of settlement to take place, creating a need for additional repair.
Polyurethane Injection (aka Foamjacking)
Polyurethane Injection, also known as foamjacking, is a very similar process to mudjacking. The difference is in the material. Instead of a mixture of mud, sand, and cement, Polyurethane Injection uses a polyurethane foam solution. Its light weight allows it to flow easily through injection sites and fill voids. The lightweight material also means that it will not create an additional round of settlement after the repair is complete. The polyurethane solution combines with loose soils beneath the concrete slab as it fills in voids, resulting in an even stronger product.
Foamjacking requires smaller injection holes as well, making for a more attractive finished product.
So Which Option is Best?
In short, both solutions are effective for concrete lifting and leveling repairs.
Mudjacking is a time tested and effective solution to lift and level concrete slabs, and it can last for long periods. However, it is less reliable and will likely need to be replaced in the future, which means an additional expense down the road.
Polyurethane Injection is a much more reliable and long-lasting solution to concrete leveling needs. In some cases, foamjacking is slightly more expensive than mudjacking solution, but more likely to save money down the road due to its long-term strength and stability.
For the full range of slab lifting applications — residential, commercial and infrastructure — see concrete leveling.
If you have concrete in need of repairs, contact us and we’ll connect you with a qualified contractor in your area.