You got a quote to replace the sunken section of your driveway, and the number made you sit down on the tailgate. Then a neighbor mentioned foam lifting: a few small holes, some foam, done by lunch.
On the right slab, it really is about that simple. On the wrong slab, it's money spent leveling concrete that belonged in a dumpster.
Here's the honest version, cons included, so you can tell which one you've got.
Lifting Fixes Where Concrete Sits, Not What Shape It's In
This one idea answers most of the "is it worth it" question.
Lifting moves concrete. It doesn't improve it. A slab that sank but is otherwise solid comes out of a lift looking about the way it did before it dropped, just back where it belongs. A slab that's cracked into chunks, flaking on top, or pitted from years of road salt comes out of a lift level, and still cracked, flaking, and pitted.
So before you weigh anything else, look at the surface and ask yourself: if this concrete were sitting at the right height, would I be happy with it? If yes, lifting deserves a serious look. If no, you're probably shopping for replacement, and that's fine.
The Real Pros
- Most of the replacement budget stays in your pocket. National cost guides put concrete leveling at less than half the price of replacing a sidewalk, patio, or walkway. Nothing gets broken up, hauled off, or poured new.
- It's light. Lifting foam weighs a few pounds per cubic foot. Mudjack slurry is in the neighborhood of 100. When soft soil is the reason the slab sank, piling less weight on that soil matters.
- It won't wash out. Cured foam is waterproof, so spring melt and a soggy April can't erode it.
- It fills the hollow, not just the gap. The foam spreads into the empty pockets under the slab as it lifts, so the slab ends up supported instead of bridging a void.
- It can fix the slope, not just the height. A patio or walk that's tipped toward your foundation can be raised so water runs away from the house again.
- The holes are small. 5/8", about the size of a dime.
- You get the slab back today. Most residential sidewalk and walkway jobs take a couple of hours. Walk on it right away and drive on it the same day. A new pour wants about a week before you park a car on it.
- Your yard survives. No skid steer chewing up the lawn, no dumpster in the driveway, no torn-out landscaping along the edges.
The Real Cons (Including the Ones Nobody Mentions)
- It can't save concrete that's falling apart. Broken into many pieces, crumbling at the edges, or scaled and spalled across the top: lifting just gives you a level version of the same problem.
- It can't lower anything. Foam only raises. If roots or frost heave pushed a slab up, the best lifting can do is raise the slabs around it to soften the edge. That works on a sidewalk. On a patio or garage approach that has to stay flat, it usually doesn't.
- You'll see the patches. Every hole gets patched, but fresh patch material rarely matches 20-year-old concrete exactly. From a few feet away the dots are hard to pick out. Up close, you'll know they're there.
- The cracks stay. Lifting doesn't erase existing cracks, and a slab that's cracked clean through can shift a little along the crack as it rises. Sealing cracks afterward keeps water out (we can caulk joints and cracks right after a lift), but you'll still see them.
- It doesn't fix the water. If a downspout or sump line has been washing soil out from under your slab, lifting fills the void that's there today. Leave the water alone and it keeps working on the soil around and below the foam.
- Foam costs more than mudjacking. Per cubic foot of fill, foam is more expensive than mudjack slurry, and mudjacking is often quoted lower upfront. You're paying for smaller holes, less weight, and fill that won't wash out. That trade is usually worth it, but it is a trade.
- There's a small chance of cracking. Concrete doesn't flex. A slab that's thin, already cracked, or wedged tight against a neighbor or the foundation can crack while it's being raised. Lifting in small increments and watching the slab the whole time keeps that risk low. It doesn't make it zero.
Foam vs. Mudjacking, Scored Fairly
Mudjacking (pumping a heavy cement-based slurry under the slab) is the other common way to lift concrete. Foam isn't better at everything.
| Foam lifting | Mudjacking | |
|---|---|---|
| Upfront cost | Higher | Often lower |
| Weight of the fill | A few pounds per cubic foot | Around 100 pounds per cubic foot |
| Hole size | 5/8", about a dime | Typically 1–2" |
| Water | Waterproof once cured | Can erode if water keeps getting underneath |
| Back in use | Walk right away, drive same day | Usually needs a day or more to set |
| Where it makes the most sense | Soft or wet soil, slabs near the house, anything you need back fast | Budget-first jobs on dry, stable ground |
We use foam. But if your concrete sits on dry, stable soil and the lowest price is the only thing that matters, mudjacking is a legitimate option, and you should know it exists.
Lift or Replace? A Decision Table
| What you're looking at | Better fix | Why |
|---|---|---|
| Sunk, but the surface is solid and it's in one or two pieces | Lift | You'd be paying to replace good concrete |
| Rocks or sounds hollow when you tap it | Lift | Foam fills the void that's causing the rock |
| Walk or patio tipped toward the house | Lift | Restoring slope away from the foundation is a lifting job |
| A few tight cracks, otherwise sound | Lift, then seal the cracks | Cracks stay visible but stop letting water in |
| Broken into many loose pieces | Replace | There's nothing solid left to lift as one unit |
| Flaking, pitted, or crumbling over most of the surface | Replace | Lifting doesn't touch surface damage |
| Pushed up by roots or frost | Depends | Foam can't lower it; raise the neighbors or replace the high slab |
| You want a new size, layout, or finish | Replace | Lifting keeps what you've got |
| Sinks a little more every spring | Fix the water, then decide | Either fix will struggle if the soil keeps washing out |
A Five-Minute Self-Check
Grab a tape measure and walk out to the slab.
- 1Would you keep this concrete if it were level?If not, stop here. You're looking at replacement.
- 2Is it one piece, or a few big ones?Big pieces lift well. Rubble doesn't.
- 3Did it go down or come up?Compare it to something that hasn't moved, like the garage floor or the house. Sunk is a lifting job. Raised isn't.
- 4Where does the water go?Look for downspouts, sump discharge, or a low spot draining toward the slab. You'll want to fix that no matter which way you go.
- 5Does it change with the seasons?If it's worse in late winter and better by May, frost is part of the story. Judge it after the ground has thawed, not while frost is still holding it up.
If you answered yes, one piece, down, and you know where the water's going, lifting is very likely worth it.
Why This Comes Up So Often Around Green Bay
Northeast Wisconsin is hard on concrete in a few specific ways, and they don't all point in the same direction:
- Loose backfill along the foundation. Stoops, walks, AC pads, and patios next to the house sit on soil that was pushed back in after the basement went in, and it keeps compacting for years. This is where lifting does its best work.
- Spring snowmelt. A winter's worth of snow melting at once saturates that loose soil. Sunken slabs often show up right after the thaw.
- Frost heave. Wet soil freezing under a slab pushes it up. That's a drainage problem first, and a lifting job only after the slab has settled back down.
- Road salt and deicers. Years of salt and freeze-thaw can flake the top layer off. That's surface damage, and lifting won't touch it.