how does concrete lifting foam work kc waterproofing infographic
July 26, 2022

Searching for information about concrete foam jacking? If so, don’t hit that back button because this article will answer your questions. We’re going to talk about what concrete foam jacking is, how it differs from mudjacking, why concrete foam jacking is better than mudjacking, and more.

Why Do Concrete Slabs Become Uneven?

Concrete slabs can become uneven due to erosion under the slab, which causes the soil to move around. Voids form, and then the slab sinks into them and becomes uneven.

Concrete slabs can also become uneven due to invasive tree roots pushing up on the slab from below. We’ve probably all seen examples of this, especially on sidewalks.

Slabs can also become uneven due to simple wear and tear. As pedestrians and vehicles use the slab, it gets compressed into the ground and eventually becomes unlevel.

What Is Concrete Foam Jacking?

Concrete foam jacking is a repair method for lifting and leveling uneven concrete slabs such as driveways, sidewalks, pool decks, patios, garage floors, warehouse floors, highways, etc. Foam jacking is a newer method for releveling uneven concrete that uses a synthetic material to relevel the slab. An older method called “mudjacking” uses a cement slurry to lift and level the slab. While mudjacking is still being used today by some contractors, foam jacking is more popular.

The foam jacking procedure involves…

  • Drilling small, dime-sized holes in the uneven slab.
  • Polyurethane foam is injected under the concrete via the holes.
  • The foam immediately begins to expand, which lifts and levels the slab.
  • The holes are patched using a compound that matches the concrete.
  • 15 minutes after the repair is complete, the slab is ready for use again.

how does concrete lifting foam work kc waterproofing infographic

What’s The Difference Between Foam Jacking and Mudjacking?

Both mudjacking and foam jacking are techniques used to lift and relevel uneven concrete slabs like sidewalks, driveways, patios, and pool decks. Mudjacking, the older method, uses a slurry containing cement, sand, and other material. In contrast, concrete foam jacking uses a rapidly expanding synthetic foam to lift and level the slab. The foam fills the voids under the slab and compresses the soil.

The foam used in foam jacking is lightweight and adds only negligible weight to the soil. In contrast, the cement slurry used in mudjacking is heavy and adds considerable weight to the soil. In some cases, mudjacking can cause the slab to sink deeper into the soil. If that happens, you’ll need another repair.

The holes used in mudjacking to inject the cement slurry under the slab are roughly the size of a quarter. The holes used in foam jacking are dime-sized. However, when the repair is complete, both are patched using a compound that matches the color of the concrete.

Foam jacking is more expensive than mudjacking. However, it’s a faster repair that lasts longer because it uses a synthetic material that won’t erode to lift the slab. Therefore, you’ll be able to go longer without needing another repair.

For more information see, The Best Repair Methods for Sunken Concrete.

Why Foam Jacking Is Better Than Mudjacking?

While mudjacking is less expensive, that doesn’t mean it’s better or the preferred solution. In our opinion, concrete foam jacking is better than mudjacking for the following reasons:

  • It lasts longer than mudjacking – The cement slurry used in mudjacking contains things like sand and soil. That makes it subject to erosion. If that happens, it will mean another repair. The material used in concrete foam jacking is synthetic and, because of this, won’t erode. Fewer repairs mean money saved.
  • It’s a quick repair – Most concrete foam jacking jobs can be completed in just a few hours, and 15 minutes after the repair is complete, you can start using the slab again. With mudjacking, you could have 24 hours of downtime before the releveled slab is ready for use.
  • The holes used in concrete foam jacking are smaller – This makes concrete foam jacking a less visible repair.

Why Do Some Say Mudjacking is Better Than Foam Jacking?

Some contractors argue that the foam used in foam jacking expands too rapidly underneath the slab and doesn’t fill all the voids. However, the temperature of the foam can be controlled. When the temperature is lowered, the foam spreads slowly and fills all the voids.

You’ll also hear some argue that the foam used in foam jacking is toxic. While it’s true that one element of the foam is slightly toxic by itself, when it’s mixed with the other element, it’s rendered harmless. The foam that comes out of the nozzle is already mixed and safe for both humans and animals.

Finally, there’s the argument that mudjacking is a longer-lasting solution. This isn’t true. As we mentioned above, the slurry used in mudjacking is subject to erosion. The synthetic foam used in concrete foam jacking isn’t.

How Much Does Foam Jacking Cost?

Concrete foam jacking costs more than mudjacking. However, it costs less than digging up and replacing the concrete – about 40% less, to be exact. So, it’s a significant saving over pouring a new slab.

Of course, the cost of concrete foam jacking will depend on where you live and the size of the area that needs lifting. The more foam used, the higher the price.

The only way to know how much it will cost to fix any uneven slab is to contact a foundation repair contractor near you that does concrete leveling and ask for an inspection and repair estimate.

If you have an uneven concrete slab and are in our service area in Kansas City, MO, contact KC Waterproofing and foundation repair today, and we’ll come out for an inspection and estimate.

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Satisfied Customer Reviews

Jeff Wolfe was excellent providing a thorough inspection, informing us about the company history, the technology and strategies utilized and our options. I would highly recommend Jeff and KC waterproofing!
First class in every way. Very friendly and accommodating. They do things the right way even if it takes much more time to get the project done. Their job of putting things back the way it was, was spectacular! They even replanted the flowers they had to dig up.
Great company and extremely easy to work with. Riley was my point of contact and he explained everything very well. After I denied working with them on one property (due to family issues) Riley happily messaged me back when I needed help with another property. The solution was a hard one to figure out, but Riley constantly made suggestions that would hopefully solve the issue without doing too much work that isn’t needed. Riley clearly explained what I needed and don’t and also gave guidance for other issues I had going on regarding window sealing.

Schylur Oakes and his crew were the ones that came and worked on my property. Schylur was extremely personable and friendly. He constantly ran back and forth from the back of the house (where the work was being done) to the front of the house to ring my doorbell and ask me if I was okay with what they were doing, if I wanted them to change anything etc. One moment he even came and asked if I really need the work to be done since there were sprinklers near my basement window and maybe that was the issue instead, not foundation and rain water. I clarified that I don’t even use my sprinklers and I still have water entering but I was glad he even brought it up and checked with me before proceeding. Schylur ended the day by having his crew clean up after themselves and showed me around and told me everything they did.

Only issue I had was payment processing was a pain. It’s 2026, I shouldn’t have to give my card number over the phone for a deposit, just send me a link to a secure site to enter it. How can I trust some random number and voice over the phone? Then for the final payment, having to manually type out and input my card information in to a tablet while it was raining was a slight nuisance. I have my own small business and use Square tap to pay. It’s not that expensive. Come on guys, if I’m using it for my little business, you can afford it for your long standing company. Just my 2 cents.
Camden came and did a thorough inspection of our foundation and explained the findings well. I felt he was honest with his recommendations and did not try to convince us to do something that wasn't necessary.
Will use KC Waterproofing and Foundation Repair again and highly recommend.
Thank you Cam!
Very professional, informative and did a great job cleaning up after the job.
Jeff was very professional and informative. Fortunately we didn't have foundation problems but if we do we know who to call.
Mario was here on time & was very informative about questions I had. A 10 out of 10. Thank you …Mario
This is the second time I've used this company. Great company. They have good employees. Fran did a great job of explaining everything, even the financing. I thought the lending company had great options. When it was time for my French drains to be installed. They came on time and ready. They even did a crawl space protective cover. Great team, they worked well together. Took the whole day but got it all done. Cleaned up well afterwards. The price was reasonable. Jackson explained everything as it went along. Kind, friendly service.
Mario serviced my sump pump today and did a good job. He also replaced tape on my wall shield. He provided excellent customer service and was willing ti come out any time needed or said to call him anytime if I had any questions.
KC Waterproofing and Foundation Repair has taken incredible care of my home through multiple visits. Gary and Davan handled my initial sump pump installation and crack repairs, and they were not only skilled but genuinely thoughtful throughout the process. We had a bit of early miscommunication, and instead of brushing it aside, they listened, acknowledged what happened, and adjusted the plan so everything aligned with what I needed.

They brought me in at every step—walking me through pump location options, explaining the exit pipe decisions, and making sure I felt confident about the work being done. Their friendliness and respect made a stressful repair feel manageable.

Later on, I had some cracks that needed to be reassessed, and Mario came out to take a look. He was incredibly kind, patient, and thorough, and he did an amazing job with the additional repairs. His calm, reassuring approach made me feel completely taken care of.

I also want to highlight Don, the manager, who is just as kind and committed to making sure customers feel heard and supported. It’s clear this team truly values doing right by people.

I’m grateful for their care and would absolutely recommend them for any foundation repair or waterproofing needs.