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.

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.

Yes, expanding foam (also known as polyurethane foam) can lift concrete. This approach, called polyjacking, involves injecting the foam rather than concrete slurry to fill voids and raise the concrete slab back into place. It’s often faster and requires smaller drill holes than traditional mudjacking, though it may come at a higher cost. Some contractors also prefer polyjacking over mudjacking for more damaged and delicate slabs.