IllustrativeConcrete Leveling Foam in Kansas City — How Polyjacking Lifts Your Sunken Slab
Polyjacking injects high-density polyurethane foam through dime-sized holes in a sunken slab. The foam expands to fill voids, compress loose soil, and lift the concrete back to level. It cures fast, so the surface is usable within hours, and it is lighter and more water-resistant than traditional mudjacking slurry.
What Polyjacking Actually Does
Polyjacking is the most precise description of what we do at PolyJacks: we inject two-part polyurethane foam through dime-sized holes drilled into a sunken slab, and the foam expands to fill whatever void has formed in the soil underneath, lifting the concrete back to level as it goes. You’ll hear the same work called concrete jacking, slab jacking, or cement leveling — different names, one process. The lift is controlled — we watch the slab millimeter by millimeter and stop each hole the moment the section reaches grade. Unlike pouring new concrete, which starts from scratch and takes days to cure, polyjacking works on the slab that's already there; unlike mudjacking, which pumps heavy slurry under pressure, polyjacking uses a foam that weighs almost nothing. Both of those distinctions matter in Kansas City, where the soil underneath your concrete has specific properties that make material weight and waterproofing genuinely important, not just marketing talking points.
The Wymore-Ladoga Clay Beneath Most KC Slabs
The underlying cause of sunken concrete throughout the Kansas City metro is the soil itself — specifically the Wymore-Ladoga clay complex that underlies most of the region. According to USDA NRCS data, this clay series runs 60 to 80 percent clay content, with a hydrologic soil group D rating and a "very high" shrink-swell classification. What that means practically: the same ground your driveway or patio sits on expands roughly 10 to 15 percent in volume when it absorbs water, then contracts back as it dries out. Over years of Kansas City's heavy spring rains followed by dry late summers and falls — roughly 40 inches of annual rainfall arriving unevenly — that swelling and shrinking opens voids beneath slabs, and the concrete drops into them. Polyjacking fills those voids with a material that doesn't participate in that cycle. Foam doesn't absorb water, doesn't swell or shrink, and doesn't erode. Once it's in place, the support it provides stays stable regardless of what the clay around it is doing.
50 to 70 Freeze-Thaw Cycles Every Kansas City Winter
Wymore-Ladoga clay's shrink-swell behavior is only half the soil story. A typical Kansas City winter brings 50 to 70 freeze-thaw transitions — days when the ground surface freezes, then thaws, then refreezes. Every time water in the soil pore space freezes, it expands about nine percent in volume. That's enough to wedge apart soil particles, shift gravel layers, and move the fine clay fraction downward as ice pushes it around. When spring arrives, the voids left behind those ice lenses are empty space — and any concrete slab above them has nothing holding it up. This is the mechanism behind most of the trip-hazard walkway joints and driveway lips we see when we come out for estimates in Olathe, Shawnee, Overland Park, and Lee's Summit. Polyjacking fills those cavities so the concrete has direct, solid contact underneath again. Improving drainage — gutters, downspouts extended at least five feet from the house, correct yard grading — addresses the deeper cause; we flag those issues on every estimate, because without drainage fixes, any lift is fighting the same cycle.
Inside the Two-Part Polyurethane Foam
The material injected during polyjacking isn't a single compound — it's two liquid components that mix at the nozzle tip and react as they're pushed through the injection hole. The foam expands 30 to 40 times its liquid volume within seconds of mixing, which means a small amount of material fills a large void quickly without requiring the high injection pressure that mudjacking slurry demands. The cured result is a closed-cell foam — fully waterproof, not porous, and rigid enough to bear structural loads. Its density is a fraction of the weight of mudjacking slurry, which matters because the soil in the void area under an already-settled slab is by definition soft or compressible; adding hundreds of pounds of heavy slurry can simply restart the settling cycle. High-density polyurethane foam adds almost no additional load to the soil while providing stable, waterproof support beneath the slab for the long term.
What Is Concrete Leveling Foam? (And Its Other Names)
People search for this material under a handful of names, and they all point at the same thing. The everyday terms — concrete leveling foam, concrete raising foam, and plain foam for leveling concrete — all describe the two-part, high-density polyurethane we inject beneath a settled slab. Some homeowners call it expansion foam for concrete, because expanding is exactly what it does — it grows 30 to 40 times its liquid volume in seconds to fill the void and lift the slab. You'll also see the shorthand poly concrete, short for polyurethane concrete leveling. Whatever you call it, the job is the same: a lightweight, waterproof foam does the work the heavy slurry in old-style mudjacking used to do, without reloading the soft soil that let your concrete sink in the first place.
How a Polyjacking Job Goes, Start to Finish
Before any drilling starts, we walk the slab and probe it to locate the low spots and determine how many injection points we need — typically four to twelve holes for a standard residential job, depending on slab size and how far it has settled. The holes are dime-sized, drilled in a pattern designed to address the void evenly rather than just pump foam into one spot. Once a hole is open, we connect the foam delivery hose and inject in short bursts, watching the concrete as the foam expands underneath. When a section reaches level, we move on. The incremental approach matters — we're lifting hundreds or thousands of pounds of concrete, and moving it too fast or unevenly can crack a slab that would otherwise lift cleanly. After all the injection points have been worked, the holes are patched with color-matched cementitious material. From first drill to final patch, most residential jobs take two to four hours. The foam finishes curing in place, and you can walk on the surface in about 15 to 30 minutes. Driveways can handle normal vehicle traffic in one to two hours, with the exception of heavy vehicles — those should stay off the freshly lifted slab for 48 hours.
Real Kansas City Jobs: What the Lift Cost
We don't publish price lists because foam volume — the main cost driver — depends entirely on the size of the void under each particular slab, which we can only measure on-site. But we can share what recent Kansas City jobs actually ran. A driveway in Olathe with significant settlement at the street joint came in at a fraction of the full replacement quote the homeowner had received. A sunken sidewalk on 143rd Street in Overland Park, creating a trip-hazard lip at the property line, cost a small fraction of its replacement quote. A Shawnee garage floor that had dropped at the overhead door threshold ran far below the replacement bid on the same floor. A Leawood pool deck settling around the coping came in at a fraction of the demolition estimate. These are real jobs. The savings — typically 50 to 70 percent compared to full concrete replacement — reflect the fact that the slab itself is structurally sound; the only thing that failed was the soil beneath it.
When Polyjacking Is Not the Right Fix
We'll tell you straight during a free estimate if this applies to your situation: polyjacking repairs voids in the soil and lifts the slab above them. It does not fix foundation walls, correct a slab cracked structurally through its full thickness, improve yard drainage, or stop tree roots that are actively lifting a concrete section from below. If the concrete is cracked badly enough that lifting it would widen those cracks further, or if the settling is being driven by an active drainage problem that is still washing soil away, polyjacking provides a temporary fix at best. We refer those cases to the appropriate specialists rather than lift a slab we don't believe will hold. What we can confidently address: settled slabs where the concrete itself is intact and the void beneath it is the cause of the drop. That describes the large majority of sunken driveways, patios, walkways, and garage floors we see across the Kansas City metro.
Get a Free Polyjacking Estimate
No charge, no obligation. Call (913) 713-7794 or fill out the contact form and we'll come look at the slab, measure the settlement, identify what's happening underneath, and give you an honest answer about whether polyjacking is the right fix and what it would cost. If it isn't the right fix, we'll say so and tell you what is. You can also use our Diagnose tool to describe what you're seeing before we visit. PolyJacks is based in Spring Hill, KS — we serve the full Kansas City metro on both sides of the state line.
What the work actually looks like
How polyjacking works — 90 seconds
Our team walks you through the three-step process: dime-sized holes, high-density polyurethane foam that fills every void and compresses the soil beneath your slab, and use within hours with no heavy trucks. Call (913) 713-7794 or book a free estimate below.
Frequently asked
What exactly gets injected under the slab during polyjacking?
A two-part polyurethane foam — two liquid components that mix at the nozzle tip and react immediately, expanding 30 to 40 times their liquid volume into a closed-cell, waterproof solid.
Why does foam work better than mudjacking slurry in Kansas City soil?
Kansas City sits on Wymore-Ladoga clay that is already unstable when wet. Adding heavy mudjacking slurry puts more load on the same soft ground. High-density foam weighs almost nothing and is waterproof, so it doesn't contribute to the soil loading that caused the settling in the first place, and it won't erode when the clay swells again.
How many holes does a polyjacking job require?
Typically four to twelve dime-sized holes for a residential job, depending on slab size and how far it has settled. We determine the number and pattern on-site before drilling.
Will the slab crack during the lift?
We inject in short bursts and watch the concrete throughout, moving incrementally to avoid over-pressuring any one area. Pre-existing cracks in structurally sound slabs don't typically worsen. Slabs that are already cracked through their full thickness are evaluated carefully before we recommend lifting.
Does polyjacking carry a warranty?
Yes — PolyJacks provides a one-year limited warranty on workmanship and materials. If the slab settles more than one-quarter inch within 12 months due to our work, we re-lift it at no charge. The warranty is transferable to new homeowners. Full terms are on our warranty page.
Is polyjacking permanent?
The foam itself is permanent — it doesn't degrade, compress, or wash out. Whether the lift holds long-term depends on the underlying cause being addressed. We flag active drainage issues and grading problems on every estimate, because fixing those is what keeps a lifted slab from resettling.
How much does polyjacking cost in Kansas City?
Recent KC jobs — from single sunken sidewalk sections to a settled pool deck — ran typically 50 to 70 percent less than replacement. Final cost depends on void size, which we can only measure on-site. Every estimate is free.
Get your free concrete leveling estimate
No obligation — and if foam isn't the right fix, we'll tell you straight.
Book your free estimate
Pick a time that works for you — free on-site inspection, no obligation. Prefer to talk? Call (913) 713-7794.