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.

Generally speaking, push piers—or steel piers—are the best option for underpinning, as they reach down to solid bedrock to find support for your foundation rather than relying on soil, which could be subject to the same issues as the soil directly below your foundation. However, the best underpinning method for your home depends on your location, how far down the bedrock is, and the type of soil in your area. Helical piers are usually the best option for sandy soil or in areas where the bedrock is too deep to use steel piers.

Mudjacking typically takes 24 to 72 hours (one to three days) to dry and cure completely before you can resume normal use. The total drying time can vary depending on the size of the project. Because the slurry mixture contains cement, it needs to harden fully to prevent the concrete slab from shifting under added weight. You should avoid walking on the concrete or placing heavy items like furniture or vehicles on the surface until it has fully set. Your concrete contractor can provide a precise timeline. As a point of comparison, if you opt for polyjacking, the polyurethane foam can dry in minutes, but it's recommended 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.