Just as their name suggests, slab piers are designed to stabilize a concrete slab that has sunk into poor soil beneath it. Unlike standard piering systems, slab piers are not intended to stabilize a foundation — the footing and vertical walls attached to it that support the home — though they are very similar in design. When properly installed a system of slab piers can permanently stabilize a sunken concrete slab and often raise it up to its original position.
As with a standard pier, a slab pier works by being driven deep into the ground to find load-bearing soil or bedrock. Constructed from heavy-gauge steel, these piers are designed to work together to support the weight of the slab and everything on it. Depending on the application, a standard round push pier or a helical pier may be used. The thing that makes it a slab pier is its bracket, which is specially engineered to work with a concrete slab.
The first step in installing a slab pier system is to expose the soil beneath the slab. This is done by coring holes in the concrete. Once the soil is exposed, either a push pier or helical pier is driven into the ground beneath until it reaches load-bearing soil or bedrock. Then, a special bracket is fitted and extended beyond the hole, so that it is able to support the concrete slab. This process is repeated as many times as recommended by the Certified Field Inspector.
Once the piers are driven in place and their brackets extended, an attempt is made to raise the slab to its original position. Once this is completed, grout is pumped into the hole to fill the void left by the settled soil and the piering process. The hole is then filled with concrete to seal it.
The installation of a slab pier system can be completed in a matter of days with minimal disturbance to interior wall finishes. Options offered by other contractors, including mudjacking, releveling grout and slab replacement typically take longer and do nothing to address the issue that caused the problem in the first place: poor soil beneath the slab.