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. 

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.

Mudjacking can be an expensive foundation repair process, but in many cases, it’s well worth the investment. This is especially true if you’re lifting a portion of sunken foundation slab back into place. In that case, mudjacking can help avoid major structural damage and even home collapse by restoring the integrity of your structure with minimally invasive procedures. Mudjacking a concrete patio, walkway, or sidewalk can be worthwhile because it removes tripping hazards and makes your outdoor area more aesthetically appealing.

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.