It only works when the concrete itself is still sound. If a slab has settled as one piece because the fill underneath washed out, lifting it is the cheaper and faster answer. If it has cracked into several pieces that move independently, there is nothing solid left to lift and replacement is the honest recommendation.
Two methods do this work. Mudjacking pumps a cement slurry under the slab through ports about the size of a soda can. Polyurethane foam injection uses dime-sized ports and a expanding foam that cures in minutes, weighs a fraction of slurry, and does not add load to soil that already failed once. Foam costs more per job and is what most of this market has moved to for residential work. Either way the slab you already paid for goes back where it belongs.
Around Winston-Salem the usual culprit is not mysterious. Slabs here sit on clay that was cut, filled and compacted when the house was built. Where the compaction was thin, or where a downspout has been dumping water against an edge for years, the fill washes or settles and the slab follows it down. That is why the estimate visit walks your drainage before anything else: lift the slab without fixing the water and it settles again.
| What changes | Effect on your price |
|---|---|
| Number and size of sunken sections | Levelling is priced by the area being lifted, so one settled walkway panel and a whole sunken garage floor are very different jobs. |
| How far it has to lift | The void under the slab is what gets filled. A deeper void takes more material, and the material is most of the cost. |
| Method | Polyurethane foam injection and traditional mudjacking price differently. Foam is lighter, cures in minutes and uses smaller holes; mudjacking uses cheaper material in larger volume. |
| Why it settled | Washed-out fill, a leaking downspout or a broken drain line all have to be dealt with or the slab will sink again. That correction is priced on top. |
| Whether the slab is still sound | Levelling only makes sense on concrete that is intact. A slab that is badly broken up gets replaced instead, and we will tell you which one you have. |
| Access to drill and inject | Interior slabs, tight crawl spaces and finished areas take longer to set up and protect. |
Call or text with the rough size and what is there now. A photo of the space answers half the questions before anyone drives out.
Someone walks the job, measures it, checks access and drainage, and leaves you a written number. Free, and there is no pressure attached to it.
Once you approve the price the work gets scheduled around the weather window. You get a start date and a realistic finish date, not a vague week.
Two methods do the same job differently, and there is a third honest answer that is neither of them.
Expanding structural foam injected through small holes. It is light, so it does not add load to the very soil that already failed. It is waterproof and will not wash out. It cures in minutes, so the surface returns to use almost immediately, and the holes are small enough to be barely noticeable afterward. It costs more per job than mudjacking and it is the better technical answer in most residential situations, particularly anywhere water was the cause.
A cement and soil slurry pumped through larger holes. The material is inexpensive, which makes it cheaper on larger areas, and it is well proven. The tradeoffs are that it is heavy, which can be a problem over soil that was already compressing, that the larger holes are visible afterward, that it can wash out if water keeps moving through, and that the slab takes longer to return to service.
Levelling is repair, not replacement, and it has limits worth stating plainly. If the slab is broken into multiple pieces, if the surface is spalling and failing independently of the settlement, if the sinking is caused by something still actively moving, or if the slab is simply at the end of its life, then lifting it is money spent to delay a replacement rather than avoid one. A contractor who tells you that is doing you a favour.
The same equipment, applied to very different consequences of a slab being out of level.
Driveways that have dropped at the garage apron, sunken walkways, patios that now slope toward the house, garage floors and settled steps. The driveway apron in front of a garage is the single most common residential case, and it matters beyond appearance because a slab sloping back toward the house sends water at the foundation. Trip hazards on a front walk are the other common driver, and levelling resolves them for a fraction of replacement cost.
Car parks, warehouse floors, loading areas and public walkways. The commercial case is usually driven by liability and by downtime. A lifted trip hazard on a walkway is a claim waiting to happen, and levelling resolves it in hours rather than closing the area for days for demolition and a 28 day cure. On warehouse floors, settled joints that jolt forklift traffic can be raised overnight without shutting the operation.
Levelling is the fastest job in concrete because nothing is poured and nothing has to cure. A sunken slab that has been an eyesore for years is usually back in service the same afternoon. The catch is that it only works on the right problem, and finding that out is the first step rather than the last.
This matters more than the lifting. A slab drops because the ground under it moved: washed out by water, settled because it was poorly compacted fill, or compressed over time. Lifting the slab without addressing an active water path just means it sinks again. Where a downspout or a broken pipe is feeding the void, that gets fixed as part of the work rather than ignored.
Levelling lifts a slab that is intact. A slab that is broken into several pieces, badly spalled or crumbling will not survive being lifted, and honest advice at that point is replacement. It is better to hear this before paying for an attempt.
Small holes are drilled through the slab in a pattern over the void. Polyurethane foam needs holes roughly the diameter of a pencil; traditional mudjacking needs considerably larger ones.
Material is pumped through the holes to fill the void underneath and then, as pressure builds, to raise the slab. The lift is controlled and watched in real time with a level, and it is done in stages across the holes rather than all at once. This is the part that looks like magic and is actually careful incremental work.
Holes are filled and finished flush. They remain faintly visible on close inspection, which is worth knowing in advance on a decorative surface.
Open joints and cracks around the lifted slab are sealed so surface water stops running straight back into the ground that just got filled. Skipping this is how a levelled slab becomes a sunken slab again.
Polyurethane foam reaches working strength within about fifteen minutes, so the surface takes traffic almost immediately. Mudjacking slurry needs longer, typically most of a day.
Far less weather dependent than pouring, which is one of its practical advantages. Very wet ground and hard frozen ground both complicate injection, but there is no cure window that rain can ruin.
Concrete Leveling & Lifting across Winston-Salem, Kernersville, Walkertown, Rural Hall, Union Cross, Pfafftown, Clemmons, Lewisville, Stanleyville, Belews Creek, King, Germanton, Oak Ridge, Colfax, Summerfield, Stokesdale, Wallburg, Midway and Welcome.
Most jobs touch more than one of these. If you are already pricing concrete leveling & lifting, it is usually worth pricing anything else you have been putting off in the same visit, because the mobilisation is already paid for.