Polyjacking can be a permanent solution to sunken concrete if you also address the underlying issue—like poor drainage—at the same time. The polyurethane material itself can last as long as or even outlast the concrete you’re lifting it with. Your sunken concrete issue will likely return if you don’t couple polyjacking with proper drainage to prevent future soil movement and sinking.

Mudjacking typically takes 24 to 72 hours (one to three days) to dry and cure completely before you can resume normal use. The exact time can vary depending on the size of the project. Because the slurry mixture contains cement, it must fully harden to ensure that added weight from walking, furniture, or vehicles won't shift the concrete slab. A professional contractor can advise you on when the surface is safe to use. For comparison, if you use polyjacking instead, the polyurethane foam can dry in just a few minutes, but it's best to wait about an hour before use.

Most houses are expected to settle over time, but foundation sinking of more than a few inches or uneven sinking of more than an inch for every 20 feet is cause for concern. Any significant or uneven sinking should be assessed by a professional to determine the cause and perform any necessary repairs. 

Mudjacking is usually reserved for light-duty slabs, like patios, driveways, and sidewalks. However, it can be an effective way to lift garage slabs and concrete around the perimeter of the home, which could harm your foundation if it’s not done properly. The risk of damage is why having a professional mudjacking company carry out the work is important. This type of slab or foundation repair is relatively inexpensive, especially if you consider that a DIY job requires that you pay to rent the necessary equipment.