Ground Screw vs Helical Pile: How to Choose by Evidence

A ground screw vs helical pile decision should not begin with which name sounds stronger, faster or cheaper. The terms are used inconsistently across markets, while the proposed products may differ in shaft geometry, thread or helix arrangement, length adjustment, head connection, installation control and verification route. First identify both candidates from controlled drawings. Then test them against the same structural reactions, ground profile, movement limits, durability target, site access, approval requirements and commercial boundary. Either candidate may be viable, neither may be viable, or both may require field verification. The responsible outcome is therefore a conditional project selection—not a universal category winner. Use the comparison below to decide what evidence must be closed before design or procurement proceeds.

1. Start with Product Geometry, Not the Sales Name

“Screw pile” and “helical pier” can be alternative names for a helical pile in some technical documents. The U.S. Unified Facilities Guide Specification (UFGS) 31 63 26.60, for example, defines a helical pile as one or more helix plates attached to a central shaft, plus a load-transfer device. WBDG, UFGS 31 63 26.60—Helical Piles

“Ground screw” can describe a different architecture. One current ICC Evaluation Service report covers a named ground-screw system with a tapered tubular shaft and a continuous helical-shaped thread extending from the conical tip onto the shaft. A separate ICC-ES report for a named helical-foundation system describes central steel shafts with one or more welded circular helix plates and optional extensions. They illustrate—not define—the architectures and are not East Baoyu certificates. ICC-ES, ESR-4226—AGS Ground Screw Systems and ICC-ES, ESR-3032—MacLean-Dixie Helical Foundation Systems

Use this first-pass comparison to frame questions, not to award the work:

The middle columns are not permanent category traits. Regional terminology and proprietary systems vary, so the controlled candidate identity remains the starting point.

2. Stop the Comparison If Neither Candidate Is Defined

A quotation cannot support foundation selection if the product behind the name remains unknown. Give each candidate an identity card linked to its drawing revision and supplier offer:

If a bidder cannot complete the card, classify the proposal as clarification required, not “lower cost.” If the candidate is outside the supplier’s cited report or the project’s approval route, record the gap instead of assuming the evidence transfers.

The gate prevents catalog values for one candidate from being compared with project calculations for the other. Both must pass the same project questions.

3. Compare Load Paths and Governing Limit States

Neither product name establishes allowable compression, uplift, lateral or moment resistance. Start with one approved reaction set and serviceability definition. State combinations, directions, eccentricities, supported-system stiffness, group effects and acceptable total or differential movement.

For each candidate, trace the load through:

• the supported structure and top connection;
• the head or bracket and its fasteners;
• the shaft, joints or couplings;
• the continuous thread or discrete helix elements;
• the surrounding soil; and
• the group of foundations and supported framing.

The governing value may come from a steel component, connection, soil resistance, buckling, lateral response, group interaction or movement criterion. A larger-looking thread or an additional helix is not proof of greater project capacity. Likewise, a catalog structural value is not automatically an installed soil resistance.

ESR-4226 illustrates this separation for one named ground-screw system: its overall allowable capacity is controlled by the lowest applicable capacity among the top connection, shaft, thread and soil, subject to its stated conditions. The UFGS helical-pile specification separately requires project design information, subsurface data, installation criteria and testing. Use these documents as examples of system thinking, then apply the standards, calculations and approvals that govern the actual project.

If lateral load or moment is material, do not reduce the comparison to axial capacity. Ask how above-ground projection, head fixity, shaft stiffness, soil response, installation inclination and supported-frame interaction are modeled and verified.

4. Use the Ground Profile to Test Reach and Constructability

The correct question is not “Which system works in clay or sand?” A soil name does not show layer thickness, variability, density or consistency, groundwater, obstructions, fill, frost, corrosion conditions or the depth of the zone expected to carry load.

Build one interpreted ground model and test each candidate against it. At minimum, reconcile:

• investigation locations and whether they represent the foundation layout;
• strata, engineering parameters and variability with depth;
• groundwater observations and seasonal uncertainty;
• fill, cobbles, boulders, hard layers, weak seams or refusal risk;
• frost depth, scour, erosion or loss of near-surface support where relevant;
• soil and atmospheric durability inputs; and
• access limits, buried services and environmental restrictions.

Then ask different but equivalent feasibility questions. Can the proposed candidate reach the intended load-transfer zone? If depth must change, is the system fixed, cuttable, jointed or extendable within its approved scope? What happens at early refusal, insufficient installation resistance, excessive torque, loss of alignment or a weaker-than-expected layer? Who can authorize a change, and what evidence releases the revised location?

The current ESR-4226 requires project-specific structural and geotechnical analysis for its named system and lists ground profile, groundwater, frost, corrosion, field verification and load-test information among the relevant inputs. That does not make its exact checklist universal; it demonstrates why a product report cannot replace the project ground model. For a detailed input route, use East Baoyu’s geotechnical data guide for ground screws.

5. Compare Installation as a Controlled Process

Both candidate types are rotationally installed, but “installed with torque” is not a complete method. A project procedure should connect equipment and measurements to the specific product, ground model, design method and acceptance plan.

Compare these controls side by side:

• drive-head compatibility and equipment torque capacity;
• permissible installation torque and how it is measured and calibrated;
• required rotation, advance and any crowd or downward force limits;
• shaft, joint, coupling or head limits during installation;
• location, inclination, cut-off/projection and interface tolerances;
• depth or termination criteria and the action at refusal or anomalous response;
• predrilling or other ground-treatment restrictions;
• handling of damaged coating, components or field modifications; and
• record fields, exception authority and release status.

The UFGS defines torque as rotational force times moment arm and describes its use in an empirical approach for helical-pile capacity. ESR-4226 gives a product-specific installation method and torque limits for the ground screws within that report. Neither statement authorizes transferring a torque-to-capacity relationship between products, geometries, soils or projects.

Treat installation torque as capacity evidence only when the design has an approved candidate-specific relationship and the field measurement lies within its scope. Otherwise, torque may still help control installation, identify variability or protect the product, while load testing or another approved method verifies performance. East Baoyu’s installation torque and ground-screw capacity guide explains this boundary in more detail.

6. Require Candidate-Specific Verification and Approval

Evidence quantity is not evidence fit. A certificate, evaluation report or test result must match the named product, report holder, geometry, manufacturing source, code/standard edition, property evaluated, installation condition and intended use. ICC-ES explains that evaluation reports identify the code or acceptance criteria, product installation, identification and conditions involved; the authority having jurisdiction remains the final decision-maker. ICC-ES, What’s in an Evaluation Service Report

Build a verification plan before commercial selection:

A product report does not approve an unlisted substitution. A proof test does not by itself establish ultimate resistance. A production log does not cure an unsuitable design. See How to Plan a Ground Screw Load Test Program for the detailed test-role workflow.

7. Make the Ground Screw vs Helical Pile Selection on Installed-System Risk

After both candidates pass the technical gate, align the commercial boundary. Compare more than the steel item price: include heads or brackets, extensions and couplings, mobilization, tooling, survey and setting-out, trial installation, testing, inspection, records, rejected or replaced units, coating repair, handling, schedule dependencies and responsibilities at the supported-structure interface.

Keep the submitted prices unchanged. Record buyer-side normalization separately, and show unresolved exposure rather than hiding it inside an arbitrary allowance. A concise selection memo should state:

1. the controlled candidate identities and project baseline;
2. compliant, deviating and unresolved requirements;
3. the governing technical and installation risks;
4. the verification and approval route;
5. the aligned installed-system inclusions and exclusions; and
6. the reason for proceeding, testing, redesigning or rejecting each option.

The final ground screw vs helical pile choice is conditional. A defined continuous-thread ground screw may suit one project, a defined discrete-helix pile may suit another, and either can be unsuitable when the ground, loads, installation access or approval evidence does not align. The defensible method is to identify the actual products, apply one common requirement set, and demand candidate-specific calculations and field controls. Only then should cost and programme influence selection. If key geometry, geotechnical inputs, movement criteria, installation limits or verification responsibilities remain open, the correct decision is not to guess a winner—it is to close the evidence gap before release.

Next Step

For a project-specific route review, send East Baoyu the structural reactions and layout, geotechnical information, durability target, candidate product drawings and data, head/interface details, installation access, test and authority requirements, destination and requested supply boundary. Ask for missing inputs, assumptions, exceptions and the applicable engineering and quotation route to be stated in writing. Contact info@baolaipipes.com or begin with the Screw Piles technical data page.

Related Resources

• Ground Screw Selection from Site Investigation
• Geotechnical Data Needed Before Specifying Ground Screws
• Installation Torque and Ground Screw Capacity
• How to Plan a Ground Screw Load Test Program

References

1. Whole Building Design Guide. UFGS 31 63 26.60—Helical Piles. November 2020, Change 2 February 2024.
2. ICC Evaluation Service. ESR-4226—AGS Ground Screw Systems. Reissued March 2026, revised June 2026.
3. ICC Evaluation Service. ESR-3032—MacLean-Dixie Helical Foundation Systems. Reissued August 2025.
4. ICC Evaluation Service. What’s in an Evaluation Service Report. March 2026.