A good slump height really depends on the project, but there is a use for nearly all slump levels. For example, low slumps are best in projects that require structure, such as curbs and roads. High slumps often require additional reinforcement, but they flow more freely into hard-to-reach spaces.

Pros often use mudjacking or polyurethane foam injection to level a sunken concrete patio. Both methods lift the slab by filling voids beneath it. After properly compacting the soil beneath it to prevent future settling, the concrete may need to be removed and re-poured for severe sinking.

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.

A sinking foundation can be lifted, most often by installing piers to re-level and support the weight of the house. Depending on the cause and extent of the sinking, other methods to lift a foundation include underpinning and mudjacking. Consult a foundation repair pro to determine the best way to lift your sinking foundation.