06/19/2026
What is poly jacking?
If you have a driveway, sidewalk, or patio that has sunken, tilted, or created a trip hazard, here is what is actually going on and how polyjacking addresses it.
Concrete does not sink because it gets heavy or weak. It sinks because the ground underneath it changes. In Minnesota, this happens regularly. Snowmelt and rain wash fine soil particles away from beneath driveways and sidewalks. Repeated freeze-thaw cycles push moisture into the ground and displace soil gradually over multiple winters. In some cases the original soil beneath the concrete was never properly compacted before it was poured. The result in all three cases is the same: a void forms, the concrete loses support, and it settles into the empty space.
Polyjacking fills that void. Small holes are drilled through the concrete at specific injection points. Expanding polyurethane foam is pumped through those holes into the space below. The foam expands, bonds to the surrounding soil, and lifts the concrete as it grows. A level sits on the surface the entire time so the crew can monitor exactly how much lift is occurring and stop at the right point.
Common places this is used: driveway aprons that have separated from the garage floor, sidewalk panels that have tilted and created uneven surfaces, garage floors that have dropped along one wall, concrete steps that have shifted away from the house, and patios that have settled unevenly after several winters.
The holes drilled are small, the foam cures in minutes, and the surface is ready to walk or drive on within hours.
Why does concrete sink?
Driveways, sidewalks, and patios settle when the soil beneath them loses density or develops empty space. The most common causes are water erosion washing fine soil particles away from under the concrete, freeze-thaw cycles displacing soil through repeated moisture and temperature changes over winter, and sub-base material that was not adequately compacted when the concrete was originally poured. The concrete itself is often structurally sound. The problem is the ground it is sitting on.
Where is polyjacking used?
Polyjacking is used anywhere concrete has settled due to a void or soil issue beneath it. Common applications include driveway aprons that have dropped below the garage floor level, sidewalk panels that have tilted and created uneven or hazardous surfaces, garage floors that have settled along one edge or corner, concrete steps that have pulled away from the house foundation, and patios that have shifted after years of freeze-thaw exposure.
What is polyjacking and how does it work?
Polyjacking is a concrete lifting method that restores sunken driveways, sidewalks, and patios by filling the void beneath them with expanding polyurethane foam. Small holes are drilled through the concrete at calculated injection points. Foam is pumped through those holes into the empty space below. As the foam expands it fills the void, bonds to the surrounding soil, and generates upward pressure that lifts the concrete. A level on the surface monitors the rise in real time so the crew can control the lift and stop at the correct elevation. The drilled holes are patched after the process is complete.
How does the crew avoid lifting the concrete too much?
A level is placed on the concrete surface during injection and monitored continuously. The crew controls the rate of foam injection and watches the level reading as the driveway, sidewalk, or patio rises. When the target elevation is reached, injection stops. This real-time monitoring prevents the surface from being over-raised, which would create a new uneven surface in the opposite direction.
How is polyjacking different from mudjacking?
Mudjacking uses a slurry mixture of cement, soil, and water pumped beneath the concrete under pressure to lift it. Polyjacking uses lightweight expanding polyurethane foam. Foam weighs a fraction of what cement slurry does, which matters because the soil beneath the driveway or sidewalk is already compromised. Foam cures in minutes while slurry takes days to set. The injection holes used in polyjacking are smaller than the ports required for mudjacking. And polyurethane foam does not dissolve or wash out over time the way cement-based material can, which means the void is less likely to re-form beneath the same surface.
When is replacement a better option than polyjacking?
Polyjacking works best when the concrete is structurally intact and the settlement is caused by a void or soil problem below it. If the driveway, sidewalk, or patio is severely cracked, broken into multiple sections with significant displacement between them, or damaged by tree root intrusion or ground heaving, lifting may not produce a usable result. Concrete that has deteriorated to the point where the surface itself is failing typically needs to be removed and repoured rather than raised.
How long does polyjacked foam last?
Polyurethane foam does not biodegrade, compress under normal loads, or dissolve in water. Once it has expanded, bonded to the soil, and cured, it is dimensionally stable. The more important variable is whether the original cause of the void has been addressed. If a drainage problem continues to erode soil in the same area, new settlement can develop in adjacent sections of the driveway or sidewalk over time
