The short answer
A successful repair can last many years, but longevity depends more on site conditions and the cause of settlement than on a universal warranty number.
Correct the source of water
Use the right lifting material
Avoid overloading unsupported slabs
Maintain joints and drainage
Monitor nearby soil movement
Common questions
Does polyurethane last longer than mudjacking?
Polyurethane is lightweight and moisture resistant, but actual longevity is site-specific. A stable base and corrected drainage matter greatly for either method.
Can leveled concrete sink again?
Yes if support is lost again through erosion, soil movement or another unresolved cause.
Use this information to compare quotes
Ask each contractor what material will be injected, how the original cause of settlement will be addressed, what is included in patching and cleanup, and what conditions are excluded from any warranty.