Helical Piers 101: A Comprehensive Guide to Screw Pile Foundations
When foundation problems arise or construction occurs on unstable soil, property owners and engineers turn to proven deep foundation solutions. One such solution is helical piers, also known as screw piles. These innovative steel piers are ideal for transferring building loads to stable, load-bearing soil layers deep beneath the surface.
At Atlas Piers of Atlanta, we specialize in the installation of helical pier systems for residential and commercial applications. In this guide, you’ll learn everything you need to know about helical piers, from what they are to how they work, their installation process, and why they are often the best choice for foundation repair and new construction support.
What Are Helical Piers?
Helical piers, or screw piles, are steel foundation elements used to support structures where surface soils lack the strength to bear loads. They consist of a central shaft and one or more helical (spiral-shaped) plates welded to the shaft. During installation, the pier is rotated into the ground like a screw, which enables it to reach stronger, more stable soil layers below the surface.
Originally developed in the 1830s for use in lighthouses, modern helical pier systems are used extensively in residential and commercial foundation repair, underpinning, and new construction projects.
Components of a Helical Pier System
A standard helical pier system includes:
- Lead Section: The first component to be driven into the ground, featuring helical plates.
- Extension Shafts: Added as needed to reach deeper load-bearing soils.
- Helix Plates: Round, spiral steel plates that generate bearing resistance.
- Brackets: Attach the installed piers to the building foundation.
The configuration (plate size, number, and shaft type) varies depending on load requirements and site conditions.
These components work together during a torque-driven installation process. The helical pier is rotated into the soil using hydraulic machinery. The torque required to drive the shaft into the ground provides a reliable indication of the pier’s load-bearing capacity, ensuring proper performance as it reaches stable strata.
How Do Helical Piers Work?
Helical piers are installed using hydraulic rotary equipment that applies torque to drive the shaft into the ground. As the screw-like helix plates advance through the soil, they displace minimal material, creating little disturbance and ensuring tight soil contact. The torque applied correlates directly with the load-bearing capacity, allowing engineers to measure capacity in real-time.
Once the desired depth and capacity are achieved, the pier is capped with a bracket and connected to the structure. The structure’s weight is then transferred through the pier down to competent soil or bedrock, bypassing the weak upper layers.
Common Use Cases for Helical Piers
Helical piers are versatile and are used across a wide range of scenarios:
Foundation Underpinning
For existing structures experiencing foundation settlement or shifting, helical piers provide a non-invasive solution. They stabilize and, in many cases, lift the structure back to its original position.
New Construction on Poor Soil
Builders use screw piles to support new homes, commercial buildings, decks, and boardwalks when constructing on expansive clay, fill material, or other problematic soils.
Limited Access and Sensitive Sites
Because installation requires smaller, lighter equipment, helical piers are perfect for sites with restricted access or environments where minimal vibration is essential (e.g., near historic buildings).
Temporary Structures
Due to their reversibility, helical piers are also ideal for temporary applications like event structures or temporary housing, as they can be removed and reused.
Step-by-Step Overview of Helical Pile Installation
- Site Preparation
- Evaluate soil conditions and structural loads.
- Mark locations for pier installation.
- Mobilization of Equipment
- Use small, hydraulic torque motors or skid-steers.
- Equipment can be easily transported and positioned.
- Installation of Lead Section
- Begin by drilling the lead section with helical plates into the soil.
- Apply constant torque until resistance indicates bearing stratum is reached.
- Addition of Extension Shafts
- As necessary, connect extensions to reach required depth.
- Monitoring Torque-to-Capacity
- Engineers track torque readings to confirm load-bearing capacity is achieved.
- Bracket Installation and Load Transfer
- Attach brackets to foundation footing or wall.
- Load is transferred to the pier system.
- Backfill and Final Inspection
- Cover exposed areas and perform structural checks.
Engineering Principles Behind Helical Piers
Helical piers rely on the principle of transferring structural loads to deeper, stable soil layers. Engineers use the torque-to-capacity ratio—a well-documented relationship that estimates axial load capacity based on the torque required to install the pier. This method ensures precise, real-time performance verification.
Key Design Considerations:
- Soil Analysis: Determines required pier length and configuration.
- Helix Plate Size & Number: Affects uplift and compressive resistance.
- Shaft Diameter & Wall Thickness: Must handle anticipated loads.
- Safety Factors: Built-in to accommodate variable soil behavior.
Many systems adhere to ICC-ES standards (e.g., AC358), which provide uniform evaluation criteria for helical pile systems, ensuring safety and performance.
Advantages of Helical Piers
Minimal Excavation
No large holes or trenches are needed, reducing mess and labor.
Fast Installation
No curing time required like with concrete—piles are ready for immediate load transfer.
Load Testing During Installation
Real-time verification provides confidence in system capacity.
Ideal for Remote and Tight Spaces
Small machinery access and low vibration make screw piles perfect for urban or sensitive areas.
Environmentally Friendly
Minimal soil displacement and potential for removal/reuse make them sustainable.
When Are Helical Piers the Best Solution?
Helical piers are often preferred over traditional concrete or push pier systems when:
- Soil near the surface is soft or inconsistent.
- Speed and minimal disruption are required.
- Foundation repair must be done with limited access or interior work.
- Lighter structures need deep support without the weight for push pier activation.
For a broader understanding of underpinning methods, read our all about foundation underpinning and explore how push piers compare by visiting our push pier solutions page.
Choose Atlas Piers of Atlanta for Helical Pile Installation
At Atlas Piers, foundation repair isn’t just a service, it’s our specialty. With over 30 years of focused expertise, we stand apart from companies that treat structural repair as an afterthought. Our certified team brings industry-leading knowledge, precision workmanship, and dedication to every project we take on, whether it’s new construction or restoring stability to existing structures.
We understand your property is one of your most significant investments, and we treat it with the care and respect it deserves. From start to finish, we stay committed to delivering results that are on time, on budget, and exceed expectations—all with minimal disruption to your home or business.
Don’t leave your foundation to chance. Trust the experts who have earned a reputation as Georgia’s most trusted name in foundation repair. Contact Atlas Piers today for a no-obligation consultation and discover how we can put our experience and passion to work for your project.
Get in touch now and see why thousands of property owners and businesses count on Atlas Piers for reliable, long-lasting foundation solutions.
