Concrete Leveling Foam in Kansas City: How Polyjacking Lifts Your Sunken Slab

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.

In practice that work is local and narrow. PolyJacks levels concrete across the Kansas City metro and does nothing else: driveways, sidewalks, patios, garage floors, pool decks, porches and commercial slabs, worked out of Spring Hill, Kansas on both sides of the state line. The service area runs roughly 35 suburbs across Johnson, Wyandotte, Jackson, Clay and Platte counties, about 50 miles out from Olathe, which covers polyjacking in Overland Park, Olathe, Shawnee, Lenexa, Independence, Lee's Summit and Kansas City, MO. The full list is on our service areas page. Every one of those towns sits on the same clay described below, which is why this metro gets one method rather than a catalogue of them.

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 commonly runs 35 to 55 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, with roughly 40 inches of annual rainfall arriving unevenly, the clay goes through that expansion and contraction cycle repeatedly. 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.

Soil classification data from USDA NRCS Soil Survey, Jackson/Johnson/Wyandotte County sheets. Freeze-thaw data from NOAA climate normals for the Kansas City metro.

For a full breakdown of why your concrete is sinking, see our guide on why concrete sinks in Kansas City.

Roughly 80 Freeze-Thaw Days Every Kansas City Winter

Wymore-Ladoga clay's shrink-swell behavior is only half the soil story. A typical Kansas City winter brings roughly 80 freeze-thaw days: 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.

You can check your specific area's settlement risk on our KC Concrete Settlement Risk Index.

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.

Is the Foam Safe Around Kids, Pets and Landscaping?

Once it cures, which takes minutes, the foam is chemically inert. It is not off-gassing, leaching or breaking down under the slab; it is a solid, closed-cell material doing a mechanical job of filling space and bearing the load.

During the injection it stays contained under the slab. Nothing is sprayed in the open air, and any minor odor during the reaction is brief and dissipates once curing is complete. Because the cured foam is waterproof and closed-cell, it does not dissolve, leach or wash out into the surrounding soil or groundwater. And because it goes in underground through dime-sized holes aimed at the void, it does not spread across the yard or contact plantings - it is a targeted fix, not a surface treatment.

The practical safety point matters as much as the chemistry: most areas are walkable in about 15 to 30 minutes and ready for vehicles in roughly 1 to 2 hours. There is no multi-day window where the work area is a hazard, and no barricades standing in the yard for days while something sets. Full detail in is polyurethane foam safe for my yard.

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.

1. Walk-on and slab probe — we walk the slab, mark the low spots, and determine how many injection points are needed and where.
2. Drilling — dime-sized holes in a pattern designed to address the void evenly.
3. Foam injection — short bursts, watching the concrete millimeter by millimeter until each section reaches grade.
4. Patching and cleanup — color-matched cementitious patches, hose and equipment removed.
5. Walk-on in about 15 to 30 minutes; normal vehicle traffic in one to two 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.

The main cost drivers are the size and depth of the void beneath the slab, the total area that needs lifting, and the number of injection points required, which on a typical residential job runs four to twelve. Each of those variables changes the volume of foam mixed and the time the crew spends on-site, which is why we measure the void on-site before quoting rather than working from a per-square-foot rate. For a fuller breakdown of what moves the number up or down before you schedule an estimate, see what polyjacking costs in Kansas City.

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.

One Specialty, One Owner, On Every Job

We can say that plainly because of how the company is built. Andrew is the owner and lead technician, and he is on every job. He spent more than a decade in the trades around Kansas City before building PolyJacks in 2024 around this one repair.

PolyJacks is independently owned and operated out of Spring Hill, Kansas. No franchise network, no call center routing you to whoever is nearest, no subcontracted crews. Call the number and you talk to Andrew; book an estimate and he shows up; when the slab gets lifted he is on the truck - one point of contact from first call to final lift.

The scope stays narrow on purpose: concrete leveling and polyjacking, nothing else. We do not offer foundation repair, drainage correction, crack sealing or concrete replacement, which is why we can tell you straight when a job falls outside it. More about PolyJacks.