Over 40 years of concrete raising experience!

Slab-Jacking VS. Poly-Jacking

What’s the difference between slab jacking (with soil cement slurry) and poly-jacking (with polyurethane foam)?

Anyone looking to raise a slab of concrete or level a set of concrete steps will no doubt find that there are two popular means of achieving the desired results: the use of a concrete slurry, or the use of a polyurethane foam sometimes referred to as “polyfill” or “poly-leveling.” Both materials are pumped down under the concrete slab through holes drilled into the slab, and the pressure created between the soil and the concrete slab forces the slab to rise. At Jacksonville Contracting Company, we prefer (and only offer) the concrete slurry (slab-jacking) method of raising concrete. This decision has been based on years of research into the polyfill method, and weighing what we consider to be the pros and cons of each method – for our business, employees, and ESPECIALLY our customers.

As a concrete leveling company, we have had many salespeople try to pitch the “polyfill benefits” to us. Every time, they try to entice us with “higher profits”, “less work for more money”, and “it’s so easy, you don’t need much training (seriously – 2 days!)”. It has never been about customer satisfaction or better quality products. After careful consideration, JCCI made the decision to NOT offer polyfill, even though it would allow us to reduce our overhead costs (including manpower, equipment, insurance, time spent on jobsites, etc.). Today, you will find many concrete leveling companies promoting the “benefits” of polyfill, but what they aren’t telling you is that most of the “benefit” is to their bank accounts, not your project!

JCCI firmly stands behind our decision and our work. Here are the reasons why:

Brief History Of Raising Concrete

Raising concrete with pumped concrete slurry – known as slab-jacking – is a method has been used successfully for over a century. The basic idea is that if the concrete has fallen due to soil erosion under the slab, then filling that void and adding more concrete underneath will not only raise the slab back to its original position, but also strengthen the slab to prevent possible further cracking, should the erosion continue. The process uses natural earthen material that is similar to the original poured concrete.

Within the past few decades, a newer method of raising concrete emerged called polyfill, or poly-jacking. This uses liquid polyurethane that is pumped under a concrete slab, which then expands and hardens. It was initially used by the government to fix sunken concrete highways, and was then appropriated by the residential concrete raising industry. It is worth noting that governments have largely moved away from using concrete for roadways as more durable materials have come along – meaning that the original use of polyfill to raise concrete started to dry up, and leaving the manufacturers of polyfill to find new markets.

Potential Hazards Of The Polyfill Method

Compressive Strength Of Concrete Slurry vs. Polyfill

Many polyfill contractors will brag about its strength. In reality, polyfill, when dried, offers a strength of 80-100 psi for most applications, and up to 250 psi at best. (“At best” refers to chemical mixtures with the optimal recipe, filling environment and installation procedure. A quick Google search will reveal that even polyfill contractors and experts disagree on the exact recipe for best results and enduring strength.) By comparison, concrete slurry offers an undisputed strength of around 600 psi. This is clearly better for heavy-duty and high-use concrete slabs such as driveways, porches and steps. Indeed, the lifting capability of concrete slurry is much greater than that of polyfill, as well.

In addition, polyfill contractors try to sell customers on the idea that they will be able to use their repaired concrete immediately. Well, this is ALSO true for concrete slurry. We literally raise concrete slabs with our equipment and heavy trucks parked right on top of them!

Environmental Factors

Concrete with polyfill attached to it cannot be recycled and MUST go to a toxic waste facility. If your concrete ever needs to be replaced, due to eventual wear & tear or home renovations, it will cost YOU lots of money to dispose of it. Absolutely NO contractor will pour new concrete on top of poly foam injection.

Carcinogens & Toxic Substances

Some contractors will claim that polyfill is more eco-friendly. This is absolutely not the case. In the polyfill method, a chemical reaction is created by mixing two materials as they are being pumped under the concrete slab. One of these materials is a byproduct processed from crude oil. According to the EPA (www.epa.gov), the two main ingredients are polymeric polyols and diisocyanate – both of which are identified as possible carcinogens and toxic substances by the EPA and OSHA. You can read more about this at www.epa.gov/saferchoice/health-concerns-about-spray-polyurethane-foam and www.osha.gov/SLTC/isocyanates. Some of the other ingredients (used in varying quantities depending upon the contractor’s particular recipe) are known neurotoxins in animals. Thus, while the material may become stable some time after installation, we feel it provides a potential work hazard to installers and potentially lasting and detrimental environmental hazards.


When mixed (and until dried), the polyfill chemicals produce a highly combustible polymer. See the articles about fires/explosions that have occurred at work sites where polyfill was being used (and the resulting lawsuits) in both Chicago and Vancouver, British Columbia.

Coverage Uniformity & Bridging

Fully filling voids with concrete slurry, before lifting, assures the proper reinforcement. Our time-tested and proven methods completely stabilize your concrete, giving uniform coverage below your slab with even, continuous support. Polyfill hardens very quickly (approximately 15 seconds) which can cause voids to be left under the concrete, otherwise known as “bridging”. Polyfill doesn’t have time to fill in the entire compromised area before it sets, leaving soil susceptible to erosion, water pooling, rodents, and insects. Your project will “look” like it has been fixed, but these voids will lead to further settling and cracking. Similarly, if a contractor tries to slow down the reaction time of Polyfill, it can travel beyond the concrete that needs to be lifted and then expand. This will cause multiple slabs of concrete (that were not meant to be raised) to be lifted above their correct location.

Foam Adhesion & Pliability

When raising a slab of concrete that is up against a foundation, foam can adhere to the foundation and lock the sunken slab into place, preventing it from being lifted back to level. This will literally NEVER happen with a concrete slurry mixture.

Also, concrete slabs are lifted one side at a time. When one side is raised, another may lower. The longer pliability time frame of concrete slurry allows the contractor to carefully manipulate the concrete slab into the proper position. If their material sets up too fast, like Polyfill does, they will not have the opportunity to move each side of the slab into optimal placement.


Some Polyfill contractors will try to sell customers on the idea that concrete slurry will erode and polyfill will not. Our concrete slurry mixture is similar to the concrete that you are looking to raise. Why are you fixing instead of replacing it? Because it lasts a really long time, just like our concrete slurry! After seeing multiple experiments with Polyfill, it is obvious that the poly floats on water. This may lead to it washing out or the concrete slab moving. If water gets under the polyfill it can put upward pressure on your concrete slab. Once your slab is pushed up above grade, it cannot be lowered and must be replaced (See the Environmental Factors section for information regarding polyfill disposal costs.)


One of the frequently cited disadvantages of this method is that the holes drilled in your concrete slab to allow for the slurry to be pumped into place are larger than those created for the newer polyfill method. In reality, the holes are only about one inch bigger, and can be filled with a well-matched concrete that often makes them very discreet. In addition, polyfill requires significantly more injection holes than slabjacking. This is because the poly material sets up in seconds, which doesn’t allow the mixture to spread out the way it needs to.

We have also heard scare tactics such as “mudjacking is messy and invasive.” While we all know that home repairs often involve some level of messiness, you can rest assured that JCCI will never leave a project dirty or messy. We pride ourselves on top notch service and customer satisfaction. If you are unsure of how serious we are about this, ask any of our previous customers. They will all say the same thing, “JCCI leaves a job site in better condition than when they arrived.” JCCI owner, Kevin, is on every jobsite and he knows his company’s reputation is on the line.


Another “disadvantage” often cited is that “using concrete to fix failed concrete” only compounds the original problem. Over one hundred years of successful use of this method begs to differ! JCCI is proud to stand behind our work. We often see polyfill companies pitching “too good to be true” warranties. They are selling you a guarantee on a product that hasn’t been around long enough to know how well it will hold up. There are reports that estimate it will only last 10-12 years before breaking down. And can you be sure that your polyfill contractor will be in business to make good on that warranty?

At JCCI we want to help you diagnose the problem, so that the source of your concrete instability can be fixed. Polyfill claims to be a “cure-all”, but most polyfill companies have not been in business very long. JCCI has over 40 years of mudjacking experience and will thoroughly investigate your concrete settling issues. We strive to give all of our customers our professional recommendations to solve underlying issues, even if that means we will be eliminating future business! We can often diagnose the problem within minutes of arriving on the job. MUDJACKING IS ALL WE HAVE EVER DONE!

Poly Foam Damage

JCCI is one of the original concrete repair companies in the field of slabjacking and mudjacking. We are a leader in our field, constantly monitoring for ways to make improvements to our company. If we thought that we could better serve our customers by using polyfill, we would add it to our existing methods of concrete leveling. We are not willing to compromise the integrity of our company to earn an easy dollar. We are proud of the work we do and our reputation as a leader in concrete and foundation repair in Maryland.

If you are in need of a concrete repair company and want to hire one that will do so safely and at a reasonable price, with a longstanding reputation and one that proudly stands behind their work, please consider JCCI for your project. We would be honored to help you!

Contact us today to schedule an on-site assessment!