Mudjacking vs. Polyurethane Foam: Which Lifts Concrete Best?
Updated Jun 2026
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When a driveway, patio, or sidewalk settles, you usually don't have to tear it out and start over. Concrete leveling raises the existing slab back to grade by filling the empty space underneath it. Two methods dominate the trade: traditional mudjacking and polyurethane foam injection. Both can produce a level slab, but they work differently and suit different jobs.
How mudjacking works
Mudjacking — sometimes called slabjacking or pressure grouting — has been used for decades. A crew drills a series of holes through the sunken slab, then pumps a cement-based slurry beneath it. As the slurry fills the void and builds pressure, it pushes the slab upward until it sits level again. The holes are patched, and the surface is usable shortly after.
The material is heavy and dense, which is part of its appeal for large or load-bearing slabs. Because it relies on a thick mixture, mudjacking generally requires larger injection holes than foam.
How polyurethane foam works
Polyurethane foam injection — often called poly lifting or foam jacking — uses an expanding two-part foam instead of slurry. The crew drills smaller holes, injects the liquid foam, and the foam expands and hardens within minutes, lifting the slab as it grows. Because the foam is lightweight, it adds little weight to the soil below.
The smaller holes are less noticeable once patched, and the fast cure time means the slab is typically ready to use quickly. Foam is also moisture-resistant once set.
Comparing the two
Think about a few practical factors rather than chasing a single "best" answer:
- Slab weight and size: Heavy or very large slabs are sometimes matched with mudjacking, while foam is popular for driveways, walkways, and pool decks.
- Soil conditions: Where soft or wet soils are a concern, the lighter weight of foam can be an advantage. A good contractor reads the soil before recommending a method.
- Hole size and appearance: Foam uses smaller holes; mudjacking uses larger ones. Both are patched, but the difference can matter on a visible surface.
- Cure time: Foam sets fast; slurry needs a bit longer before full use.
Which should you choose?
There isn't a universal winner. Many reputable companies offer both and recommend one based on your slab, your soil, and how the area is used. The most important step is an in-person inspection: a pro who comes to your home can see how far the slab has settled, check for voids and drainage issues, and explain why a given method fits your situation.
Questions to ask before you book
When you compare local providers, ask which method they recommend and why, how they handle the holes and cleanup, whether they address the drainage or soil issue that caused the settling, and whether they stand behind the work. A contractor who explains the trade-offs clearly — instead of pushing one product for every job — is usually a safer bet.
The bottom line
Both mudjacking and polyurethane foam can restore a sunken slab without a full replacement, often in a single visit. Rather than deciding the method yourself, focus on finding an experienced local company, getting a written estimate after an inspection, and understanding how they'll keep the problem from coming back.