Polyurethane foam lifting and mudjacking
Both methods do the same basic thing: fill the hollow under a sunken slab and use that pressure to bring the concrete back up.
A slab sinks because the soil beneath it has compressed, washed out or never been packed well in the first place. The concrete itself is usually fine. Leveling leaves the concrete where it is and fixes what's under it. The crew drills through the slab, injects material into the hollow, and keeps injecting under controlled pressure until the slab rises to the height they're after.
How do the two methods compare?
| Polyurethane foam | Mudjacking | |
|---|---|---|
| What goes in | Two-part expanding foam | Cement and soil slurry |
| Hole size | Small, roughly 5/8 inch | Larger, about 1 to 2 inches |
| Weight on the soil | Very light | Heavy |
| Back in use | Usually the same day | Often a day or more |
| Water resistance | Doesn't absorb water | Can erode if water keeps running under it |
| Relative cost | Usually higher | Usually lower |
What does a lifting visit look like?
- Inspection. The contractor measures the drop, checks for cracks running clear through, taps for hollow spots, and looks at where your downspouts and sump line empty.
- Hole layout. Holes are marked in a pattern based on the slab's size and where it needs the most lift.
- Injection. Material fills empty space first, then lifts the slab gradually. Going slowly matters, because forcing a slab up fast can crack it.
- Cleanup. Holes are patched with cement-based grout, and joints and cracks are sealed so the next spring thaw doesn't start the cycle over.
When is lifting the wrong answer?
A slab broken into many small pieces, one with a badly scaled or spalled surface, or one sitting over an active sinkhole or broken drain line may not be worth lifting. A trustworthy contractor will say so instead of selling you a lift that won't hold.
What drives the price?
- Total square footage and number of slabs
- How far the concrete has to come up and how big the hollow is
- Foam versus slurry
- How easily equipment can reach the slab
- Crack repair and joint sealing after the lift
We don't publish prices. The contractor sets the price after measuring the slab, sounding out the void underneath and finding out why it dropped, so treat any figure you hear before that visit as a ballpark.
Where we connect you with help
Common questions
How long will a lifted slab stay level?
That depends far more on drainage than on the material. If water is routed away and joints stay sealed, a lift can last many years; if a downspout keeps emptying beside it, it may settle again.
Is foam better than mudjacking in Rochester's climate?
Foam's light weight and water resistance are real advantages in a freeze-thaw climate, but mudjacking still works well on many slabs and often costs less. Ask the contractor to explain the choice for your slab.
Related services
- Driveway and garage floor leveling
- Sidewalks, walkways and patios
- Steps and stoops
- Joint sealing and crack filling
More background: Rochester concrete leveling guide.
Is a slab tipping, dropping or holding water?
Call and a Rochester-area concrete lifting contractor will come look and tell you whether it can be raised.