Helical Piers
Screw-in foundation elements for fast installation with immediate load capacity.
Helical piers (also called screw piles or helical piles) are steel foundation elements with one or more helical bearing plates welded to a central shaft. They are installed by rotating (screwing) the pier into the ground using hydraulic torque motors mounted on compact equipment. As the helical plates advance through the soil, they create minimal disturbance and generate immediate bearing capacity — no curing time required. Originally developed for lighthouse foundations in the 1830s, modern helical piers are engineered to precise torque-to-capacity correlations that allow real-time verification of load capacity during installation. They work in tension, compression, and lateral loading, making them suitable for a wide range of applications from residential foundation repair to commercial new construction and temporary structures. Helical piers are particularly advantageous where vibration-sensitive conditions exist, where no spoils generation is acceptable, or where immediate loading is required.
Technical Specifications
Common Applications
Installation Process
- 1Position hydraulic drive head at pile location using excavator or skid steer
- 2Attach lead section with helical plates to drive head
- 3Advance pier into ground while monitoring torque with calibrated gauge
- 4Add extension sections as needed to reach competent bearing stratum
- 5Continue advancing until target torque (correlating to design capacity) is achieved
- 6Cut pier shaft at design elevation
- 7Attach foundation bracket or pile cap connection hardware
- 8Load structure onto pier system (immediate loading permitted)
Frequently Asked Questions
How quickly can helical piers be installed?
A single helical pier can typically be installed in 15–45 minutes depending on depth and soil conditions. A residential foundation repair project (8–12 piers) can often be completed in a single day.
Can helical piers be loaded immediately after installation?
Yes — this is a major advantage. Unlike concrete piles that require curing time, helical piers develop their full capacity during installation and can be loaded immediately.
What is the torque-to-capacity relationship?
Helical pier capacity is verified in real-time using installation torque. The empirical relationship is: Capacity = Kt × Torque, where Kt is a factor typically ranging from 9 to 12 ft⁻¹ depending on shaft size and soil type.
Do helical piers work in clay soils?
Yes, helical piers work well in clay soils. The helical plates bear on undisturbed soil below the active zone of seasonal moisture change, providing stable support regardless of surface soil shrink-swell cycles.
How long do helical piers last?
Hot-dip galvanized helical piers have a design life of 75+ years in most soil conditions. In highly corrosive soils (low pH, high chlorides), additional protection or sacrificial thickness may be specified.
What size equipment is needed for installation?
Helical piers can be installed with compact equipment — a mini excavator or skid steer with a hydraulic torque motor attachment. This allows access through standard 36-inch gates and into confined spaces.
Are helical piers removable?
Yes — helical piers can be unscrewed and removed, making them ideal for temporary structures. This is a unique advantage over other deep foundation types.
What is the maximum depth for helical piers?
While depths of 100+ feet are possible with extension sections, most helical pier installations reach 15–50 feet. Depth is limited by torque capacity of the equipment and buckling resistance of the shaft.