Concrete curb ramp work in progress during an accessibility upgrade

POLYJACKING COST

Polyjacking Cost: What Foam Lifting Runs

Polyjacking (also called foam jacking) injects expanding polyurethane under the slab. It costs more than mudjacking. You get ⅝ in. holes instead of 1–2 in., and you can drive on it the same day.

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Photo: Oregon DOT / Wikimedia Commons · License

HOW POLYJACKING WORKS

Small holes. Fast cure.

01Find the void
Soil under the low end washed out or packed down. The slab is hanging over an empty pocket and has tipped into it.
02Drill ⅝ in. holes
The crew drills a few pencil-sized holes, about the size of a dime, through the low section.
03Inject the foam
Two-part polyurethane is injected. It expands to fill the void within seconds and pushes the slab up.
04Patch and use it
Holes are capped with cement patch. Foam cures in about 15 minutes, so you can usually drive on it the same day.

Foam weighs about 2–4 lb per cubic foot, so it adds almost no load to weak soil.

BEFORE / AFTER

What the crew is actually fixing.

Sidewalk panels that dropped below the curb and the next slab, leaving a raised edge — **Trip edge, water pooling.** One end sank into a washed-out pocket. Panels no longer line up and rain runs the wrong way.

Technician injecting polyurethane foam through a slab while a dial gauge on the next panel tracks the lift — **Lift while watching a gauge.** The tech injects through the slab while a dial indicator on the next panel shows exactly when it’s level.

After

Flush joints, drainage restored. The void is filled, the slab sits back at grade, and the holes are patched. Same concrete, no tear-out.

Photos: credits & licenses. Diagrams are illustrations, not to scale.

NATIONAL PRICE CONTEXT

$8–$25 per square foot, typical nationally

Minimums run $300–$700 or more. Foam weighs about 2–4 lb per cubic foot, and mud slurry about 100 lb, so foam adds far less weight to the soil that already let the slab sink.

These are national reference figures, not local market data, a guarantee, or a substitute for a written estimate after an on-site inspection.

What shapes an estimate?

A good quote names the panels, the material, the hole layout and what’s not included. If it just says “level driveway, $1,800,” ask for the rest in writing.

Factor	National reference / question
Injection material	Expanding polyurethane foam
Common estimate factors	Slab size, voids, lift height, access, and repair scope
Reported minimums	$300–$700 or more; contractor and project conditions vary

Questions to bring to a quote

What may be causing this section to settle, and how will you assess the area below it?
Which lifting method and material do you recommend for this slab—and why?
How will you handle drainage, nearby panels, cracks, or access limitations?
What is included in the written price, and what could add cost?
What curing, use, and maintenance guidance should I follow?
What warranty applies, and what conditions are excluded?

SOURCE NOTES

National ranges, linked to their source.

Cost figures were checked against these HomeGuide pages. Estimates are broad national ranges and may change over time.