Helical Steel Pier - Also referred to as a screw pile. A helical pier consists of a round or rectangular shaft with a screw shaped plate or multiple plates. The helical pier is rotationally screwed into the ground and atop it is placed a bracket which supports the foundation. Helical piers are chosen for foundation repair when it is not practical to use the weight of the structure during the driving process. Typically helical piers are driven to a specified minimum depth and rotational torque limit, consistent with the soil type. Helical piers consistently achieve greater penetration dept than concrete piers. Greater depth puts the underpinning system below the zone of seasonal moisture change.