What to look for
Hidden voids reduce slab support. Filling those voids can stabilize the concrete and, when needed, create controlled lift.
Hollow sound when tapped
Visible erosion at edges
Rocking or flexing panels
Progressive settlement
Gaps where soil has washed away
Why the cause matters
Leveling treats the slab position and the unsupported space beneath it. If active erosion, plumbing leaks, irrigation, downspouts or major soil movement remain uncorrected, the same area can lose support again.
A visual inspection cannot diagnose every subsurface condition. Large structural movement, building-foundation symptoms or unusual site conditions may justify evaluation by an appropriately qualified contractor or engineer.
Questions homeowners ask
Can you fill a void without lifting the slab?
Yes. Injection can be stopped after support is restored if lifting is not desired.
What material is used to fill voids?
Depending on the project, contractors may use polyurethane foam, cementitious slurry or other engineered fill materials.
Next steps
Compare the repair methods and decide whether lifting or replacement better fits the condition of the concrete.