Settlement of building foundations can often be arrested and the building restored to near its original condition by using proprietary underpinning systems. The systems increase foundation load-bearing capacity with steel piers that are pushed or screwed into the ground beneath the footings or floor slab. Jacking against the piers raises the foundation back to its original elevation, and the increased bearing capacity from the piers provides permanent support. It's smart business sense for owners to repair settlement damage to ensure the structure's resale market value.
Two different types of underpinning systems are available. One system uses sections of galvanized or epoxy-coated steel pipe for the piers. The piers are point bearing and are driven to bearing strata with a hydraulic drive unit. Another system uses screw piles with solid steel shafts. The lead section, with one or more helixes attached, provides the needed bearing capacity. The piers are screwed into the ground with an electric or hydraulic drive unit and extensions are added during driving until bearing strata is reached. Both systems can be installed from inside or outside the building.