Polyjacking and mudjacking can both be effective solutions for sinking concrete, but they have key differences. Polyjacking, which uses expanding polyurethane foam, is often considered a better option because the foam is significantly lighter than the cementitious material used for mudjacking. This reduced weight puts less pressure on the underlying soil and lowers the risk of future sinking. Polyjacking is suitable for any sinking concrete slab, while mudjacking is typically only recommended for non-structural concrete, such as sidewalks, patios, pool decks, and driveways. The primary drawback of polyjacking is its cost, which can be up to four times higher than mudjacking—as much as $25 per square foot compared to a maximum of about $6 per square foot for mudjacking.

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. 

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.