Highlights
Concrete leveling lifts sinking slabs by filling spaces underneath
This process addresses unevenness or water issues
Mudjacking uses a heavy mixture of cement and mud
Poly leveling uses a lightweight polyurethane foam
Both leveling methods tend to cost less than full slab replacement
Whether you notice your front steps starting to shift to one side, deck furniture looking like it may creep off a tilting patio, or maybe your walkway or driveway becoming uneven—sinking concrete is tough to ignore. These issues are often signs of problems underneath your concrete, which might not be solved by simply replacing the slab. Learn how concrete leveling may be the solution you need to put your concrete back in place.
What Is Concrete Leveling, and Does Concrete Leveling Work?
Concrete slabs sink and may become uneven over time for various reasons. Common causes include water washing away the soil holding up a slab. Other times, soil or tree roots expand or contract, moving slabs along with them.
Concrete leveling is a process used to fill voids under sagging concrete slabs, including steps, porches, patios, sidewalks, and driveways. The process involves drilling holes into the existing concrete and pumping a leveling material through those holes and underneath the slab. The material stabilizes loose soil and raises the level of the sunken slab back to where it belongs.
"There are some cases where concrete leveling doesn’t always work and it’s not a foolproof method," says Angi Expert and owner of DiBara Masonry, Matt DiBara. "In these instances, the slab isn’t lifted high enough or breaks after being raised, which then requires a slab replacement."
When Do You Need Concrete Leveling?
Level surfaces are especially important for concrete driveways, walkways, and sidewalks, where uneven slabs could cause people to trip or catch the wheels of scooters and bicycles. You may also want to fix sinking outdoor patios where you spend a lot of time. Tearing up and replacing a slab can be messy and time-consuming—not to mention tough on your lawn and landscaping—so you may prefer concrete lifting if conditions are right.
Often, you’ll be able to see where a section of the concrete slab is no longer at the same level as the slabs next to it. Any slab that has settled at least a quarter-inch below its original level may be able to be fixed using concrete leveling. You may also notice water issues in your basement when it rains, which can sometimes be caused by concrete patios settling next to your house.
Other signs are less obvious. Voids can develop under concrete without causing immediate problems. Look for slabs that rock when driven over or stepped on or make hollow sounds when tapped.
When Not to Use Concrete Leveling
If your concrete slab is cracked into several pieces that are each smaller than a square foot, concrete leveling is unlikely to fix the issue. This type of damage requires a full replacement.
Different Concrete Leveling Options
There are two main methods to level concrete: mudjacking and poly leveling. You can hire professional concrete leveling services to use either method for your project. Here are the main differences between the two methods and what projects they’re best suited for:
Mudjacking
Mudjacking involves “jacking” concrete up from below using a mud-like mixture of cement, water, soil, and sand. First, several holes about two inches wide are drilled into the existing concrete slab. The material is then injected through the holes to lift the slab from below to its original height.
Pros of Mudjacking
Costs less than poly leveling or complete slab replacement
Doesn’t require heavy equipment or large crews
Lasts 5–10 years
Works for intact walkways, patios, steps, and driveways
Cons of Mudjacking
Takes up to 48 hours to cure
Drilling large holes can cause cracks in your slab
Material is not waterproof and can deteriorate
Material is very heavy and can worsen sinking
Won’t work for garage floors, basements, foundation repair, pools, or heavily damaged slabs
Poly Leveling
The other concrete leveling method is poly leveling, or polyurethane foam concrete raising. Like in mudjacking, small holes are drilled into the slab. Instead of cement and mud, however, poly leveling injects a polyurethane foam that expands to level the sunken concrete. You may hear this method called “slabjacking,” though that term is also sometimes used for mudjacking.
Pros of Poly Leveling
Doesn’t require heavy equipment or large crews
Lasts at least 10 years
Cures in under an hour
The holes required are smaller, just 5/8-inch in diameter
Waterproof foam is extremely lightweight
Works for garage floors, basements, foundation problems, and pools
Cons of Poly Leveling
Costs more than mudjacking
Won’t work on heavily damaged slabs
Entry points of holes on the slab’s surface may be a different color than the original material
Is Concrete Leveling Worth the Cost?
If your slab is intact, concrete leveling is often better than full slab replacement. For a replacement, you’ll end up paying to remove the old slab and dispose of materials, deliver new concrete, and then have a new slab poured.
Breaking up and removing the existing concrete costs $2 to $6 per square foot. You’ll then pay an additional $4.50 to $10.50 per square foot to pour a new slab—bringing the total cost to $6.50 to $16.50 per square foot.
Compare these costs to concrete leveling. Mudjacking is the least expensive option at $3 to $6 per square foot. For poly leveling, you’ll spend anywhere from $5 to $25 per square foot. Before you decide, consider calling in a concrete contractor to get a quote and ensure the underlying issues causing your concrete to sink are properly addressed.
