Patio Leveling Terms Explained: A Plain-English Glossary
If you're getting quotes to fix a sunken patio in Des Moines, the jargon piles up fast. This patio leveling glossary breaks down the terms you'll hear from contractors and see on estimates, in plain English. Use it to read a quote line by line, ask sharper questions, and spot the difference between a real fix and a patch job. Nothing here requires a construction background, just a few minutes.
- Concrete Leveling: raising a sunken slab back into place
- Slab Jacking: the umbrella term for lifting slabs
- Mudjacking: lifting with a pumped cement slurry
- Polyurethane Foam Injection: lifting with expanding foam
- Self-Leveling Concrete: a pourable overlay that flattens itself
- Settling: soil sinking under your slab over time
- Void: an empty gap under the concrete
- Expansive Clay Soil: soil that swells wet and shrinks dry
- Frost Heave: winter freezing that pushes slabs up
- Injection Ports: the small drilled holes used for lifting
- Cure Time: how long before the slab can take weight
- Crack Filling: sealing cracks to keep water out
- Resurfacing: a new thin top layer over worn concrete
- Tripping Hazard: an uneven edge that catches feet
- Slab Replacement: tearing out and pouring new concrete
- Joint Sealing: caulking the gaps between slab sections
Patio Leveling Repair Methods: How Sunken Concrete Gets Lifted
These are the repair methods themselves, the words that show up in the first line of most quotes. This section of the patio leveling glossary covers what each method actually does to your slab.
Concrete Leveling
Concrete leveling is the process of raising a sunken concrete slab back to its original position instead of replacing it. Crews pump material under the slab through small drilled holes, and the pressure lifts the concrete. It costs less than tear-out and replacement and keeps your existing slab if it's still in good shape. When a quote says "leveling," ask which lifting material the contractor plans to use, because that choice drives cost and cure time.
Slab Jacking
Slab jacking is the general term for any method that lifts a sunken slab by pumping material underneath it. Mudjacking and polyurethane foam injection are both types of slab jacking. Some contractors use the terms interchangeably, so if a quote just says "slab jacking," ask which material they mean. The answer tells you a lot about weight, cure time, and hole size.
Mudjacking
Mudjacking is a leveling method that pumps a slurry of cement, soil, and water under a sunken slab to lift it. It's the older, time-tested approach, and it often costs less than foam. The slurry is heavy, so it works best where the soil underneath can carry the added weight. The drilled holes are larger than foam holes, roughly the size of a soda can, and they get patched when the job is done.
Polyurethane Foam Injection
Polyurethane foam injection is a leveling method that pumps expanding foam under a slab through small drilled holes, where it hardens and lifts the concrete. The foam is light, cures in minutes rather than hours, and needs holes about the size of a penny. It usually costs more than mudjacking per job. Our guide comparing mudjacking vs. polyurethane foam walks through when each one fits a patio.
Self-Leveling Concrete
Self-leveling concrete is a pourable cement product that flows out and flattens itself to create a smooth, level surface. It fixes low spots and rough surfaces on top of a slab, but it does not lift a sunken slab or fix the soil problem underneath. If your patio has dropped as a whole piece, self-leveling concrete alone won't solve it. It's a surface fix, not a structural one.
Resurfacing
Resurfacing means applying a thin new layer of concrete or overlay material on top of an existing slab to renew its look and texture. It hides surface wear, small pits, and hairline cracks. Like self-leveling concrete, it does nothing about sunken or tilted sections. A good contractor will level first and resurface second, never the other way around.
Slab Replacement
Slab replacement means breaking out the old concrete, hauling it away, and pouring a new slab in its place. It's the right call when concrete is crumbling, badly cracked into many pieces, or too damaged to lift in one piece. It costs more and takes longer than leveling, and new concrete needs days to cure before use. If a contractor recommends replacement, ask them to show you why the slab can't be lifted instead.
Root Causes in the Patio Leveling Glossary: Why Your Patio Sank in the First Place
Understanding what pushed or pulled your slab out of place helps you judge whether a proposed fix addresses the cause or just the symptom.
Settling and Patio Leveling
Settling is the gradual sinking of a concrete slab as the soil beneath it compresses or washes away. It's the most common reason patios, driveways, and sidewalks end up uneven. Settling usually happens slowly, a fraction of an inch per year, which is why homeowners often don't notice until a door of the patio table wobbles or water pools against the house. Leveling fixes settled slabs; it does not stop future settling if the soil problem continues, so ask what's causing yours.
Void
A void is an empty pocket of space under a concrete slab where soil used to be. Water erosion, poor compaction during construction, and burrowing animals all create voids. A slab spanning a void can look fine until it cracks or drops suddenly under weight. Filling voids is a core part of leveling work, and it's worth asking any contractor how they'll confirm the void is fully filled.
Expansive Clay Soil
Expansive clay soil is soil that swells when it gets wet and shrinks when it dries out. Central Iowa sits on a lot of it, and that swell-shrink cycle rocks slabs up and down season after season until they crack or settle unevenly. It's the main reason patio leveling is such a common repair around Des Moines. We cover the full story in why patios sink on expansive clay soil.
Frost Heave
Frost heave is the upward push on a slab that happens when water in the soil freezes and expands beneath it. Iowa winters deliver plenty of it. Heave lifts sections unevenly, and when the ground thaws, the slab often settles back crooked or cracked. If one corner of your patio rises every winter, frost heave is the likely culprit; our post on frost heave damage to patios explains the fix options.
The Details: Terms You'll See on Quotes and During the Job
Injection Ports
Injection ports are the small holes drilled through a slab so lifting material can be pumped underneath. Foam jobs use penny-sized holes; mudjacking holes run larger. Crews patch the holes with concrete when the lift is done, though the patches may stay visible as small round spots. Ask how many holes the job needs and how they'll be finished.
Cure Time
Cure time is how long a repair material needs to harden before the slab can carry weight again. Polyurethane foam cures within minutes to about an hour. Mudjacking slurry needs a day or more before heavy use, and new poured concrete needs several days. Cure time matters if the slab is your only path to a door or if you park on it, so make sure the quote spells it out.
Crack Filling
Crack filling means sealing cracks in concrete with a flexible or cement-based filler to keep water out. Water in a crack erodes the soil below and freezes in winter, making everything worse. Crack filling is cheap insurance after a leveling job, and many contractors bundle crack repair with the lift. It won't hold two settling slab pieces together, though, so filling alone isn't a fix for a sinking patio.
Joint Sealing
Joint sealing means caulking the gaps between slab sections, and between the slab and your foundation, with a flexible sealant. Those joints are the easiest path for water to reach the soil under your concrete. Sealed joints slow erosion and reduce frost heave damage. If a leveling quote includes joint sealing, that's a sign the contractor is thinking about keeping the slab level, not just making it level today.
Tripping Hazard
A tripping hazard is any raised or sunken edge in a walking surface that can catch a person's foot, often a lip of half an inch or more between slab sections. Uneven concrete on patios and walkways is a common source. Beyond the safety risk to family and guests, tripping hazards can create liability concerns for homeowners. Leveling removes the height difference at the joint, which is usually a faster and cheaper fix than grinding or replacement.
Using These Terms
What this patio leveling glossary gives you is the vocabulary to read a quote line by line and ask the questions that matter: what material, how many holes, what cure time, and what happens to the soil problem underneath. If a number on an estimate still doesn't make sense, the patio leveling cost guide breaks down what drives the price. You don't need to become an expert; you just need to know enough to hear the difference between a straight answer and a script.
If you need concrete leveling, Des Moines Concrete Leveling Pros can help.
Prefer to talk it through? Call +15155828701 — a quick call is usually the fastest way to get a straight answer for your situation.
