Ground Screw Solar Mounting System
Ground screws provide a foundation interface for compatible ground-mounted PV structures. Select the screw geometry, embedment, corrosion protection and rack connection from site conditions, field testing and project structural requirements—not from a generic “concrete-free” claim.
- Site-Specific Foundation
- Field Load Verification
- Rack Interface Matching
- Terrain & Soil Review
- Corrosion Consideration
Ground Screw and PV Racking Are Different Design Layers
The ground screw transfers axial and lateral foundation loads into the soil. The rack above transfers module and environmental loads into that foundation through a compatible post, leg, flange or adapter. Both interfaces must be verified for the selected products.
- Confirm the exact ground-screw model and head / flange / U-base connection.
- Confirm the racking system is designed for that foundation interface.
- Use site-specific foundation capacity rather than a generic screw length or diameter.
- Coordinate final screw elevation and tolerance with rack adjustment limits.
Soil and Field Testing Drive Ground-Screw Selection
Ground screws can be useful on difficult sites, but suitability should be established from the actual subsurface and project loads.
Subsurface Conditions
Soil profile, rock/refusal risk, groundwater, frost depth and site variability across the array.
Field Load Testing
Tension/pull-out, lateral and other tests required by the foundation design, with displacement criteria and test locations documented.
Installation Data
Installation torque, pre-drilling, embedment depth and acceptance criteria where these are used by the selected foundation system.
Corrosion Environment
Soil corrosivity, coating/galvanizing, expected exposure and any project-specific corrosion protection requirements.
Match Screw Geometry and Connection to the Site
Length, shaft geometry, helix/thread design and head connection should be treated as model-level engineering inputs.
Screw Body & Embedment
Use the foundation design and field results to set screw model, embedment and any pre-drilling or refusal procedure.
Head / Rack Interface
Flange, U-base, post adapter or other connection must match the racking leg/post and the project load path.
Coating & Durability
Specify the actual steel grade, galvanizing/coating and connection materials for the soil and atmospheric exposure.
Ground Screws Can Support Different Racks When the Interface Is Engineered
A ground-screw foundation can be paired with a compatible fixed-tilt or other ground-mount architecture, but the upper structure is not defined by the screw alone. Verify leg/post spacing, connection details, tolerance and foundation reactions for the selected rack.
- Use the rack manufacturer's documented foundation interface.
- Coordinate screw spacing with the structural table/row design.
- Confirm adjustment available for terrain and installation tolerance.
- Check that foundation loads used in field testing match the structural design basis.
Use the Foundation Installation Procedure for the Selected Screw
The exact sequence depends on the screw product, equipment, subsurface and engineering plan.
Set Out Locations
Survey foundation points from the approved array and structural drawings.
Prepare the Location
Follow the specified refusal, pilot-hole or pre-drilling procedure where required by the soil and product.
Install & Record
Install to the required depth/elevation and record alignment, torque or other acceptance data required by the system.
Connect the Rack
Install the compatible post, leg or adapter and verify tolerances before the upper racking is completed.
Use Product- and Site-Specific Foundation Data
| Foundation product | Exact ground-screw model, geometry, steel/coating and rack-interface connection. |
|---|---|
| Site basis | Geotechnical/subsurface information, groundwater/frost conditions and terrain relevant to installation. |
| Field verification | Required tension/pull-out, lateral or other tests and any torque/installation acceptance criteria. |
| Structural reactions | Foundation actions from the selected PV racking and governing project load combinations. |
| Installation | Equipment, pre-drilling/refusal procedure, target embedment/elevation, alignment and recordkeeping requirements. |
| Corrosion | Coating or galvanizing and connection-material compatibility for the actual soil and exposure environment. |
| Project outputs | Foundation layout, screw schedule, rack interface, testing/acceptance requirements and installation documentation within the agreed scope. |
Send the Site and Foundation Information
Provide project location, site/topographic information, module layout, structural design criteria and any available geotechnical or field-test data so the ground-screw foundation and rack interface can be reviewed.
- Project location and site / terrain information
- Geotechnical report or soil information if available
- PV module datasheet and preliminary layout
- Structural design criteria and foundation reactions if available
- Preferred racking system / post interface if already defined
Ground Screw Foundation Questions
Are ground screws and helical piles the same product?
No. They are related screw-type foundation families, but geometry, installation, connection and structural design data can differ. Use the exact foundation specified for the project.
Are ground screws suitable for every rocky site?
No. Ground screws can be effective on challenging or rocky terrain in some systems, but refusal risk, pre-drilling, installation equipment and field verification must be evaluated for the actual site.
What testing may be required?
Depending on the design, field testing can include tension/pull-out and lateral tests, with installation torque or other acceptance data recorded where the selected foundation system uses those criteria.