Foundations settle for many reasons, including poorly compacted fill, poor drainage, or soil dessication. For residential and light commercial applications, steel underpinning systems are viable solutions for stabilizing and raising sunken foundations. Steel piers are hydraulically pushed or screwed into the soil and attached to brackets installed beneath and anchored to the footings. In many cases, soils analysis is not required because the load carried by the pier is determined during installation.
Two different types of steel pier systems are available. Push piers consist of sections of galvanized or epoxy-coated steel pipe that are driven into the soil with a hydraulic ram. Helical piers use screw piles with steel shafts. The lead section, with one or more helixes attached, provides the needed bearing capacity. The piers are screwed into the ground with a hydraulic torque motor.