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.

There is no real alternative to underpinning, although mudjacking and polyjacking are other repair methods that can add support from underneath your foundation. Rather than placing supportive piers under your structure, these involve pumping a material under your slab to lift a sunken section back into its original position. Polyjacking, in particular, is sometimes a suitable solution for stabilization issues under slab foundations, but underpinning is often accepted as the best and most permanent solution.

The average cost for mudjacking is around $1,200, though prices can range from $300 to $3,400. On a per-square-foot basis, you can expect to pay between $3 and $8, with an average of about $5 per square foot. The final cost depends on several factors, including the square footage of the concrete, the type of slab, its accessibility, whether it is load-bearing, and the type of material used to lift it. Generally, lifting a driveway, small patio, or sidewalk is less expensive than lifting a slab foundation or garage floor.

The polyurethane used for polyjacking will expand and cure in 15 to 30 minutes. After that point, your slab will be safe to walk on and even drive on in the case of a sidewalk or concrete driveway. Double-check with your concrete lifting specialist to confirm a curing timeline, as products can differ.