How concrete leveling is done
Lifting settled concrete back to grade without replacing it. Either mudjacking, which pumps a cement slurry beneath the slab, or polyurethane foam, which is injected through smaller ports and expands to raise it.
Scope
What the job includes
Cause investigation
Establishing why the slab moved. Downspout discharge, a broken drain, uncompacted backfill against a foundation, or a plumbing leak each need addressing or the settlement returns.
Void assessment
How much empty space exists under the slab determines how much material is needed and whether lifting is even the right answer versus stabilizing in place.
Port drilling
Mudjacking uses one to two inch holes; foam uses ports around five-eighths of an inch. Smaller holes are less visible after patching, which matters on a decorative or visible surface.
Injection and lift
Material is pumped in stages while the slab is monitored with a level. Lifting is done incrementally across multiple ports rather than forcing it up at one point, which would crack it.
Joint and crack sealing
Open joints and cracks are sealed afterwards so surface water stops running straight back under the slab and washing out the support again.
Port patching
Holes are filled and finished. They remain visible on close inspection; anyone claiming they will be invisible on a weathered slab is overselling.
Sequence
Step by step
Survey and cause diagnosis
Levels taken across the slab, void probed, and the drainage or plumbing cause identified. A contractor who does not ask where the water goes has not diagnosed anything.
Method selection
Foam or slurry chosen against soil conditions, load, access and how visible the port holes will be. Weak soils favor lightweight foam; cost-sensitive utility slabs favor mudjacking.
Drill injection ports
Ports drilled in a pattern across the settled area, sized to the method. Pattern spacing determines how evenly the lift distributes.
Inject and monitor lift
Material pumped in stages, moving between ports, with continuous level monitoring. Going slowly is what prevents cracking the slab during the lift.
Seal and patch
Ports patched, joints and cracks sealed so surface water no longer runs beneath. This last step is what protects the work and is sometimes quoted separately.
Preparation
What to do before the crew arrives
Doing these first shortens the job and usually the invoice.
- Look at where your downspouts discharge and where surface water runs, because that is the most common cause and often the cheapest thing to fix.
- Measure and photograph the settlement now, so you have a baseline to compare against if it moves again later.
- Rule out a plumbing leak if the settlement is near a sewer or supply line, since lifting over an active leak is money spent twice.
- Combine every slab you want lifted into one visit rather than calling separately, because mobilisation is a large share of a small job.
- Accept that patched port holes will be visible on a weathered slab and decide in advance whether that matters on a decorative surface.
- Clear vehicles, furniture and planters from the work area and provide access for equipment and hose runs.
Questions about the work
How much does concrete leveling cost?
Mudjacking runs roughly $3 to $6 per square foot and polyurethane foam roughly $5 to $25, with foam reaching about four times mudjacking at the top of its range. Small jobs are usually priced against a minimum charge rather than by area, so a single sunken step can cost more per foot than a whole driveway. Combining areas into one visit is the main way to improve value.
Is polyurethane foam better than mudjacking?
It is better in specific ways rather than universally. Foam is far lighter, so it does not add load to soil that has already failed; it cures in minutes so you can use the surface almost immediately; and its injection ports are much smaller. Mudjacking costs considerably less and is perfectly appropriate on stable soils and utility slabs where hole size does not matter.
How long does concrete leveling last?
If the underlying cause was addressed, a properly executed lift can last many years, effectively as long as the slab itself. If the cause was not addressed, expect it to settle again, sometimes within a single wet season. The durability question is almost entirely about drainage and soil rather than about which injection product was used.
Can any sunken concrete be lifted?
No. Lifting works on slabs that are still structurally sound, even if cracked in one or two places. A slab that has broken into multiple pieces that move independently, or one that is severely spalled and deteriorated, is a replacement candidate. A contractor willing to lift anything regardless of condition is worth a second opinion.
How long does the work take?
Most residential jobs are completed in a few hours to a day. With polyurethane foam the material cures within minutes, so a driveway can often take traffic the same day. Mudjacking uses a heavier slurry that needs longer before full load, commonly a day or so. Both are dramatically faster than removal and replacement, which involves cure time measured in days to weeks.
Will the holes be visible afterwards?
Yes, on close inspection. Foam ports are around five-eighths of an inch and mudjacking holes one to two inches; both are patched, and both remain discernible on a weathered slab because the patch material will not match aged concrete exactly. On a utility surface this is irrelevant; on a decorative or stamped surface it is worth discussing before you commit.
Is leveling cheaper than replacing the concrete?
Substantially, usually by a wide margin, and it is also much faster and less disruptive. Replacement means demolition, disposal, forming, pouring and cure time, plus a new slab that will not match the color and finish of the surrounding concrete. Replacement becomes the right answer when the slab itself has failed rather than merely settled.
What causes concrete to settle in the first place?
Almost always movement in the soil underneath rather than a defect in the concrete. Common causes are water washing out fines along a downspout or drainage path, backfill that was never properly compacted when the structure was built, erosion, drought-related soil shrinkage, and leaking supply or drain pipes. Identifying which one applies is the difference between a repair and a recurring expense.
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What this site is
Lexington Concrete Lifting is a referral site, not a contractor. We do not hold a license, own a truck, or send a crew. We research concrete leveling pricing and practice, publish what we find, and hand your request to a vetted local company in Lexington.
That company quotes, schedules, and stands behind its own work, and it contracts with you directly. We do not mark up the price, and you pay us nothing.