What Is Mudjacking?
Mudjacking is a concrete leveling technique that uses a slurry of pulverized limestone and cement to raise settled slabs. The slurry is pumped through small holes drilled in the concrete, filling voids beneath the slab and lifting it back to the desired elevation.
Also called slab jacking, slab raising, or stone slurry grout leveling, mudjacking has been used for decades and is one of the most established concrete repair methods available. It's particularly well-suited for larger areas where the heavier fill provides solid, long-lasting support.
How Mudjacking Works
- Inspection — The settled concrete is assessed to determine the cause of settlement and the amount of lift needed.
- Drill access holes — Holes measuring 1-2 inches in diameter are drilled through the sunken slab at strategic intervals.
- Pump slurry — A mixture of pulverized limestone, cement, and water is pumped beneath the slab at low pressure. The slurry fills voids and compacts the soil.
- Lift the slab — As the void fills, the pressure gently raises the concrete back to level. The process is monitored to ensure precise lifting.
- Patch and clean up — The access holes are patched with concrete or grout, and the area is cleaned.
After mudjacking, the surface typically needs 24-48 hours to cure before it can handle heavy loads. Foot traffic is usually fine sooner, but vehicle traffic should wait.
When to Choose Mudjacking
Mudjacking is a good choice when:
- The settled area is large — mudjacking is cost-effective for bigger slabs
- The slab needs heavy, dense support beneath it
- Budget is a primary concern — mudjacking material costs less than polyurethane foam
- The concrete is thick and can accommodate 1-2 inch drill holes
Advantages of Mudjacking
- Lower material cost — The limestone-cement slurry is less expensive than polyurethane foam, especially for larger areas
- Dense, heavy fill — The slurry compacts soil and provides solid, weight-bearing support
- Proven track record — Mudjacking has been used successfully for decades
- Good for large slabs — Cost-effective for driveways, warehouse floors, and other large surfaces
Limitations of Mudjacking
- Larger drill holes — 1-2 inch holes are more visible than the 5/8 inch holes used for polyurethane foam
- Heavier material — The added weight of the slurry can stress already weak soils
- Longer cure time — 24-48 hours before heavy use, compared to 15 minutes for polyurethane foam
- Not ideal for weak soils — If the soil beneath the slab is very weak, the heavy slurry may not be the best option
Mudjacking vs. Polyurethane Foam
Both methods are effective, but they have different strengths. Mudjacking is more cost-effective for large areas, while polyurethane foam is lighter, faster-curing, and uses smaller holes. For a detailed comparison, see our mudjacking vs. polyurethane foam guide.
You can also learn more about polyurethane foam leveling or concrete leveling in general.
Cost Factors
Mudjacking cost depends on the size of the area, the amount of settlement, site accessibility, and the number of slabs involved. In general, mudjacking costs less per square foot than polyurethane foam and 50-70% less than full concrete replacement.
See our concrete leveling cost guide for a detailed breakdown.
Frequently Asked Questions
Yes. Mudjacking, slab jacking, slab raising, and stone slurry grout leveling all refer to the same process of pumping a cement-based slurry beneath a settled slab to lift it back into place.
Mudjacking is a long-lasting repair when the underlying cause of settlement is addressed. The limestone-cement slurry is dense and stable, but if water continues to erode the soil beneath the slab, settlement can recur. Correcting drainage issues as part of the project helps ensure long-term results.
Mudjacking can be performed in cold weather, but the cement-based slurry may take longer to cure in freezing temperatures. Polyurethane foam is generally better suited for winter work because it cures quickly and is not affected by freezing temperatures.