Concrete lifting sounds like magic — a sunken slab comes back to grade in an afternoon. Here's the actual process, step by step, so you know exactly what happens when a crew shows up at your Salt Lake City home.
Concrete lifting restores a sunken slab by pumping material underneath it. The injected material — either a cement-based slurry (mudjacking) or expanding polyurethane foam — fills the voids left by settled soil and then, as pumping continues, hydraulically raises the slab back to its original elevation. No demolition, no new concrete, no weeks of waiting. Most residential jobs take a few hours.
The differences between mudjacking and foam leveling are real but secondary to the process itself: both methods follow the same five steps. Our full mudjacking vs. foam comparison covers when each method is the better choice.
Every legitimate lift starts with measurement, not pumping. A specialist will:
The diagnosis matters more than the sales pitch. If a contractor blurts out a price from the truck without measuring anything, get a second opinion. And note: the assessment should be free and no-pressure — you're hiring judgment, not just a pump.
With the settled sections mapped, the crew drills a grid of injection holes through the slab — typically spaced a few feet apart across the low areas, with extra holes near joints and edges where the lift needs the most control.
The hole pattern isn't random: it's planned around the slab's support points so pressure distributes evenly. On garage floors and pool decks, holes are placed to avoid radiant heating lines or post-tension cables — another reason the assessment step comes first.
This is the part that does the work. Material is pumped through the holes into the void underneath, and it performs two jobs in sequence:
The two materials behave differently here:
| Mudjacking (slurry) | Polyurethane foam | |
|---|---|---|
| Material | Cement, soil, and water mixed on-site | Two-part polyurethane, mixed at the nozzle |
| How it lifts | Slurry fills the void; hydraulic pressure raises the slab | Foam expands rapidly to fill the void; controlled expansion raises the slab |
| Control | Good — the operator moves hole to hole, lifting in stages | Excellent — foam reacts in seconds, so the lift can be feathered precisely |
| Waterproof | No — slurry can erode if water keeps flowing underneath | Yes — closed-cell foam won't wash out |
| Weight added | Significant — slurry is heavy, a concern on weak soils | Minimal — foam weighs a few pounds per cubic foot |
On Utah's soft lake-bed clays, foam's light weight is a real advantage: pumping tons of heavy slurry onto soil that already failed once can restart settlement. That's the core trade-off in our method comparison — not just price, but physics.
Here's what separates a professional lift from a cracked slab: constant measurement. As each section rises, the crew checks elevation with a straightedge, a level, or a laser, targeting the original grade — usually matching the high (unsettled) edge of the slab or the structure it meets, like the garage floor or foundation.
The lift is deliberately uneven in sequence — one hole gets a partial pump, the crew moves to the next, then comes back. Lifting one corner of a slab faster than the rest is how concrete cracks mid-job, so a good operator raises everything together in small increments. You'll see the crew pausing, measuring, and adjusting far more than you'd expect. That's the job being done right.
This is also the step where your input matters. Before pumping starts, confirm the target elevations: "flush with the garage floor," "draining away from the house," "no lip at the sidewalk joint." A good crew verifies the finished grade with you before they move on.
Once the slab is at grade, the injection holes are patched with concrete and the surface is cleaned up. Then comes the step that determines whether the lift lasts: sealing the joints. Every joint and crack that could channel water back underneath gets caulked. Water is what caused the settlement in the first place — letting it straight back under the slab would undo the work. Our after-lift maintenance guide covers exactly what to seal and when.
The crew should also flag drainage fixes while they're there: downspout extensions, regrading soil against the slab, or redirecting a sump discharge. These aren't upsells — they're the difference between a lift that lasts and one that doesn't. See how long lifting lasts for the full picture.
| Phase | Mudjacking | Polyurethane foam |
|---|---|---|
| Assessment | 20–45 minutes | 20–45 minutes |
| Drilling | 30–60 minutes | 20–40 minutes (smaller holes) |
| Injection & lift | 1–3 hours | 1–2 hours |
| Sealing & cleanup | 30 minutes | 30 minutes |
| Ready for use | ~24 hours before vehicle traffic | 15–30 minutes — same day |
Compare that with replacement: demolition, forming, pouring, and a cure time of several days to a week before you can drive on it — at 2–3x the cost. Lifting isn't just cheaper; it's dramatically less disruptive. That's why lifting beats replacement whenever the slab itself is still sound.
None of these are arguments against lifting — they're arguments for hiring the assessment, not just the pump. A free, measured, written quote costs you nothing and answers every one of these questions for your specific slab.
The lift fixes the position of the slab; fixing the cause is a separate step. Lifting fills the void and restores grade, but if a downspout keeps dumping water under the slab, settlement can return. A good contractor diagnoses the cause during the assessment — see why Utah concrete settles — and addresses it with drainage fixes alongside the lift.
A few inches is routine — the typical residential lift raises slabs 1–4 inches. Beyond that, the contractor will assess whether the slab and the soil underneath can take it. Slabs that have dropped much further, or that are badly cracked from the movement, may be better candidates for replacement.
Most residential lifts take a few hours, start to finish — assessment included. Polyurethane foam is usually faster than mudjacking, and you can drive on foam-lifted slabs in 15–30 minutes. Mudjacking needs roughly 24 hours before vehicle traffic. Compare both methods in our mudjacking vs. foam guide.
Mudjacking leaves 1–2 inch holes; foam leveling leaves holes around 5/8 inch — roughly the size of a dime. The contractor patches them with concrete and seals the surface. On a driveway, the patches are noticeable if you look for them but blend in over time. Foam's smaller holes are one reason homeowners choose it for visible areas.
When done correctly, no — the whole point of monitoring the lift is to raise the slab evenly. The risk comes from contractors who pump aggressively without measuring, which can crack a slab by lifting one corner faster than the rest. This is why the monitoring step matters, and why the cheapest quote isn't always the best one. See our cost guide for what fair pricing looks like.
Usually not for the whole job, but plan to be there for the first 30 minutes. The contractor confirms the target elevations with you, and you'll want to see the initial lift. After that, most homeowners go about their day — the crew calls you out to verify the final grade before they seal everything up.
Related reading: Mudjacking vs. foam: honest comparison · Concrete lifting cost guide · 7 signs your concrete is sinking
Describe what's sinking — a local specialist will assess it, explain the method they'd use, and quote the fix in writing.