Solar Ground Screw Foundations

Ground screw foundations for solar PV ground-mount systems replace traditional concrete pier footings with a driven, threaded steel pile that is installed in minutes per unit using a hydraulic torque head attachment on a standard mini-excavator or skid steer. The pile develops its bearing capacity through the helical plate bearing mechanism — the helical plate acts as a screw thread, advancing through undisturbed soil and developing axial and uplift resistance through the plate’s bearing area against the surrounding soil. This makes ground screws the dominant foundation choice for solar ground-mount installations worldwide: they are installable in any weather without curing time, produce no spoil or excavation waste, and provide real-time capacity verification through installation torque monitoring. Each pile is certified to hot-dip galvanized protection to EN ISO 1461 or ASTM A123 for corrosion resistance throughout a 25–35 year solar project design life. For the complete application guide covering structural design, embedment requirements, racking connection details, and project case studies, see our Solar Ground Mount Foundation →

Utility-Scale Solar Foundation Systems

Utility-scale solar farm foundations — supporting single-axis trackers, fixed-tilt systems, and bifacial panel arrays across hundreds of megawatts of installed capacity — require a foundation system that can be driven at production rates of 200–500 piles per day per machine while simultaneously meeting the structural demands of wind-dominated load combinations that govern in large open-terrain sites. Solar Earth Screw utility-scale ground screws are produced from S355J2 structural steel (355 MPa minimum yield) in hollow circular sections (OD 76–114 mm, wall 5–8 mm), hot-dip galvanized to 85–115 µm zinc thickness, and tested to ASTM D1143 and D3689 static load testing protocols to confirm site-specific torque-to-capacity correlations before production installation begins. The American Ground Screw Products catalogue confirms that ground screws provide similar structural performance to concrete piers with 97.5% less embedded carbon — making the utility-scale ground screw specification a compelling sustainability advantage in addition to a programme schedule and cost advantage. For technical specifications, load test data, and utility project references, see our Utility-Scale Solar Foundation Systems →

Residential Ground Screw Solutions

Residential solar ground-mount and carport foundation systems present a different design challenge from utility scale: the structural loads are lower, but the installation must be achievable with compact equipment (often a hand-held or walk-behind torque driver for small systems), the aesthetic integration into landscaped garden environments is important, and the adjustability of the pile head after installation is valuable to accommodate minor layout changes during the installation process. Solar Earth Screw residential ground screws are available in compact diameters (48–76 mm OD) and shorter length options (600–1,500 mm) optimised for residential soil profiles and racking connection requirements — with hot-dip galvanized protection standard across all residential product dimensions. The Krinner foundation analysis confirms that installation of residential ground screws often takes only one or two days, and that the foundations can support a load immediately after installation with no curing delay — enabling a typical residential solar ground mount to go from site layout to panel installation in a single day. For product selection, connection hardware details, and residential project installation guidance, see our Residential Ground Screw Solutions →

Fence Post Ground Screw Anchors

Ground screw fence post anchors replace driven wooden posts, poured concrete collars, and rammed post footings with a clean, adjustable, removable steel foundation that provides equivalent or superior uplift and lateral resistance with a fraction of the installation time and ground disturbance. The fence post ground screw is designed to accept standard fence rail post sections directly into the pile head socket — available in square section (40×40 mm, 50×50 mm, 60×60 mm) and round tube configurations — making it compatible with the full range of timber, steel, and composite fence post systems used in agricultural, perimeter security, and decorative fencing applications. Because no concrete is used, the fence line can be adjusted, relocated, or completely removed and the site restored to its original state without any foundation demolition or waste removal — a significant advantage for temporary fence lines, construction site perimeters, and agricultural applications where field layouts change between seasons. For product dimensions, post socket compatibility, and installation guidance for different soil types, see our Fence Post Ground Screw Anchors →

Deck Foundation Screw Systems

Deck and patio foundation screw systems provide a code-compliant, permit-ready alternative to poured concrete pad footings and post-in-ground deck construction — eliminating the frost heave risk that makes concrete pad footings structurally unreliable in freeze-thaw climates, and providing a fully adjustable head height that simplifies the levelling of decks on sloping sites. Solar Earth Screw deck foundation screws are designed to penetrate below the frost depth in the applicable climate zone — typically 600–1,200 mm below grade in temperate climates — providing frost-stable bearing from undisturbed soil that cannot heave seasonally because the pile point is below the zone of frost penetration. The GBGS ground screw analysis confirms that modern ground screws deliver impressive long-term performance and stability even in challenging soil types, with their galvanised steel construction protecting against corrosion and load testing during installation confirming structural adequacy — making them a technically superior alternative to the concrete pad footings that most residential deck codes accept as the default. For beam pocket dimensions, joist connection options, height adjustment range, and permit documentation for deck foundation screws, see our Deck Foundation Screw Systems →

Greenhouse Ground Screw Fasteners

Greenhouse and polytunnel foundations must satisfy a specific combination of structural requirements: adequate resistance to wind uplift on the roof structure (which is lightweight but presents a large wind-exposed area), lateral resistance against wind-induced racking of the frame, and sufficient axial compression capacity to support the self-weight of steel or aluminium framing without differential settlement that would misalign the glazing or polycarbonate panel system. Ground screw foundations meet all three requirements in a single installed element — the same pile simultaneously provides the axial, uplift, and lateral resistance required — and do so without the concrete footings that prevent the seasonal deep-ripping and bed-preparation treatments that agricultural greenhouse operators require to maintain soil fertility and drainage over multi-decade facility lifespans. Solar Earth Screw greenhouse foundation screws are available in structural hot-dip galvanized steel configurations compatible with standard commercial greenhouse floor-rail, column-base, and anchor-plate connection details, with custom head configurations available for specialist glazed structures and research facility greenhouses. For structural load specifications, frame connection details, and greenhouse foundation product selection guidance, see our Greenhouse Ground Screw Foundations →

Definition and Basic Structure

A ground screw — also called a helical pile, screw pile, or earth screw — is a structural foundation element consisting of a hollow circular steel shaft with one or more helical bearing plates welded to the lower portion of the shaft at defined pitch intervals. Unlike an auger, which excavates soil and produces spoil as it penetrates, a true helical pile advances through undisturbed soil by following the helical geometry of its bearing plate — the pitch of the helix determines the vertical advancement per revolution, and each helix plate cuts through the same soil path to minimise disturbance. The Foundation Technologies CHANCE pile documentation confirms that a helical bearing plate is one pitch of a screw thread — being a true helical shape, the helices do not auger into the soil but rather screw into it with minimal soil disturbance. The basic structural components of a ground screw assembly are: the shaft — the hollow circular tube that carries combined torsional, axial, and bending loads; the helix plate(s) — the circular plates welded to the shaft at the designed pitch that develop the pile’s bearing capacity in the surrounding soil; the coupling — a bolted or sleeve connection that allows extension sections to be added when the design embedment depth requires greater length than can be installed in a single piece; and the pile head — the connection interface between the installed pile and the structural element it supports (racking post, deck beam, fence rail, or structural column).

How Ground Screws Work vs Traditional Foundations

Ground screws develop their structural capacity through a fundamentally different mechanism than poured concrete foundations — and this difference produces their key performance advantages. A concrete pad footing resists structural loads through the mass and bearing area of the concrete in contact with the soil surface — it requires excavation to place, time to cure, and adequate bearing pressure from the upper soil layers immediately below the excavation level. A ground screw develops its resistance through the bearing capacity of the helical plate acting against the undisturbed soil at the depth of embedment — meaning that the soil at the pile point (which has not been disturbed by excavation) provides the structural resistance, and the pile can be extended to reach stronger, deeper soil layers if the upper soil profile is inadequate. The Stop Digging comparative analysis confirms that ground screws are significantly faster to install than concrete foundations, can be fitted and ready to build on within the same day, and can be completed in just a few hours — versus the concrete foundation process that involves excavation, reinforcing, forming, pouring, and curing before it is ready for structural load. A detailed side-by-side comparison of ground screw and concrete performance across installation time, material cost, frost stability, structural capacity, environmental impact, and end-of-life recyclability is available at Ground Screw vs Concrete: A Complete Engineering Comparison →

Benefits Over Conventional Foundations

Ground screws offer a series of engineering, environmental, and commercial advantages over conventional concrete foundations that compound across the scale of a project — from a single residential deck with six piles to a utility solar farm with 10,000+ installed foundations:

• Same-day load bearing — ground screws support structural load immediately after installation with no cure time, versus the 28-day concrete design strength curing requirement
• Real-time capacity verification — installation torque monitoring provides a continuous, real-time record of the pile’s load capacity during installation via the Qu = Kt × T correlation, confirming structural adequacy for every pile as it is installed
• No excavation, no spoil — the screw-in installation produces no excavated material, eliminating spoil disposal cost, muck trucking, site restoration, and the schedule delays associated with excavator mobilisation
• Frost stability — piles installed below the frost depth are not subject to seasonal frost heave that affects concrete pad footings in freeze-thaw climates
• Fully removable and recyclable — ground screws can be unscrewed and removed at end of project life, leaving the site in its original condition — the pile steel is fully recyclable, versus the landfill or crushing cost of concrete removal
• Adjustable head height — pile head height can be adjusted after installation to accommodate site topography, simplifying levelling on sloped sites without the step-footing complications of concrete construction
• 97.5% less embedded carbon — the American Ground Screw Products catalogue confirms that ground screws provide similar structural performance to concrete with 97.5% less embedded carbon, making the foundation type selection a meaningful sustainability decision for solar project carbon reporting
• All-weather installation — ground screws can be installed in rain, cold, and even frozen ground conditions where concrete cannot be placed, eliminating weather-dependent programme delays

Rapid Installation and Reduced Project Time

For solar farm EPC contractors, foundation installation speed directly governs project schedule — and therefore the date of commercial operation, the first revenue generation, and the ability to honour PPA commissioning milestones. Ground screw installation at production rates of 200–500 piles per day per machine is achievable on well-prepared sites with established installation crews, versus the 40–80 concrete piers per day achievable with a comparable concrete pier drilling and pouring operation that additionally requires cure time before the racking installation crew can follow. The Solar Power World ground screw analysis confirms that ground screws and helical piles are increasingly preferred for challenging utility solar sites precisely because of their installation speed and the flexibility to adapt to variable soil conditions in real time — adjusting pile length and configuration in the field based on the torque-depth profile observed during installation rather than requiring the design changes, re-engineering, and programme delays that concrete pier redesigns involve. For a 20 MW solar farm requiring 3,000 foundation piles, replacing concrete piers with ground screws typically reduces the foundation installation programme from 8–12 weeks to 3–5 weeks — a schedule saving that can determine whether the project meets its planned commissioning date.

Minimized Site Disturbance and Environmental Impact

Solar farms are increasingly developed on agricultural land, ecologically sensitive sites, and areas subject to environmental permit conditions that restrict site disturbance, topsoil removal, and surface water runoff management. Ground screw foundations minimise all three impacts simultaneously: no excavation means no topsoil removal or stockpiling; no concrete means no cement wash water, no aggregate delivery and stockpiling, and no concrete truck cleaning on site; and the screw-in installation compacts the soil in the immediate pile zone rather than disturbing it, maintaining soil structure and drainage pathways under the array. The Krinner analysis confirms that with ground screw foundations, the soil ecosystem is not disturbed, remains intact, and rainwater can trickle down under the foundations directly — eliminating the need for separate drainage management that concrete pads require. For projects with environmental mitigation conditions requiring a post-construction habitat management plan, the full removability of ground screws at end of design life — the site can be fully restored without foundation demolition — is a demonstrable environmental advantage over concrete that is increasingly cited in planning and permitting documentation for solar farm development consent applications.

Engineered Capacity for Wind and Uplift Loads

Wind uplift — the vertical tensile force generated by wind suction on the underside of a solar panel array — is typically the governing load case for solar farm foundation design, exceeding the compressive gravity loads from the racking system and panel weight in all but the lowest wind speed zones. Ground screws develop their tensile (uplift) resistance through the same helical plate bearing mechanism that provides compressive capacity — but in the upward direction — making their uplift capacity directly predictable from the installation torque record via the Kt correlation, and directly verifiable through ASTM D3689 static tension load testing. The PierTech helical pile solar guide confirms that helical screw piles offer stability for solar panels in all soil types — with the helical plate configuration providing both bearing resistance in compression and break-out resistance in tension simultaneously. Uplift-critical solar tracker foundations in high-wind zones (ASCE Basic Wind Speed above 130 mph, or coastal / hilltop sites) require careful load case analysis to confirm that the pile’s tensile capacity under the factored uplift combination (1.0W + 0.9D under ASCE LRFD) is adequate — and that the installation torque criterion used to accept production piles is calibrated to the uplift demand, not just the compression demand. For the engineering basis of uplift resistance design, safety factors, and load testing methodology that confirms ground screw uplift capacity for solar foundations, see our Load Design Standards for Ground Screws →

Matching Products to Soil Conditions

Soil conditions are the primary driver of ground screw product selection — governing the pile diameter, embedment depth, helix plate diameter and configuration, and the minimum installation torque criterion that must be achieved to confirm adequate capacity at each pile location. The helical pile design guide confirms that the softer or less dense the terminating soil strata, the larger the helix plates required to generate the necessary torque and capacity — confirming that the helix diameter specification is directly linked to the bearing capacity of the soil at the installation depth. In practice, the product selection logic follows the soil profile: dense sand or firm clay (SPT N > 20) — standard single-helix configuration, 200–250 mm helix diameter, standard embedment depth; loose sand or soft clay (SPT N 10–20) — larger helix diameter (250–300 mm) or double-helix configuration to develop adequate bearing capacity, increased embedment depth to reach a competent bearing stratum; gravelly or cobble soil — reduced helix diameter (150–200 mm) with reinforced tip configuration to penetrate obstructions; made ground or fill — extended embedment to penetrate through the fill into the natural soil bearing stratum below. The Helical Pile World torque correlation guide confirms that the torque factor Kt ranges from 3 to 10 ft⁻¹ for pipe shaft sections depending on shaft diameter and soil type — confirming that a site-specific soil investigation is required before the Kt factor and minimum torque criterion can be established for a production installation programme. For a complete guide to ground screw product selection by soil type, SPT and CPT data interpretation, and embedment depth design logic, see our Soil Conditions Guide for Ground Screw Design →

Load Capacity and Design Requirements

The correct ground screw product is the one whose structural capacity — in axial compression, axial tension (uplift), and lateral bending — meets or exceeds the design demand for each load combination at the project site, with the required safety factor or partial factor applied to the characteristic capacity. This requires three parallel design checks: (1) geotechnical capacity — the helix plate bearing capacity in the soil at the design embedment depth, confirmed by either the torque correlation method (Qu = Kt × T) or the individual plate bearing method from soil investigation data; (2) structural section capacity — the pile shaft’s yield capacity in axial compression, tensile uplift, and bending under the factored load combination; and (3) connection capacity — the pile head connection’s ability to transfer the structural loads from the racking or building system to the pile shaft without failure. Load demand for a specific project is derived from the applicable structural loading code — ASCE 7-22 in North America or Eurocode 1 in Europe — using the project-specific wind speed, snow load, and dead load parameters. A systematic explanation of how to derive design loads, how to apply safety factors, and how to select the pile section that satisfies all three capacity checks is available at our Load Calculation Guide for Ground Screw Foundations →

Corrosion Protection and Coating Considerations

Corrosion protection specification is the third critical dimension of ground screw product selection — after structural capacity and soil conditions — because it determines whether the pile’s structural capacity is maintained for the full project design life or whether it degrades through section loss at an accelerating rate once the zinc coating is depleted. The base level corrosion protection for all Solar Earth Screw products is hot-dip galvanizing to EN ISO 1461 — providing 85 µm average zinc coating thickness for standard soil environments (C3 corrosivity, pH 5.5–8.5, resistivity above 5,000 Ω·cm). For more aggressive site environments — coastal locations within 2 km of the sea, saline agricultural soils, industrial sites with elevated sulfate or chloride levels, or any site with soil pH below 5.5 — an enhanced galvanizing specification (115 µm or 215 µm local minimum, achievable with reactive silicon-controlled steel) or a duplex coating system (hot-dip galvanizing plus paint topcoat) is required to ensure coating service life through the project design period. The selection of the correct corrosion protection level requires a site soil investigation confirming pH, resistivity, chloride content, and sulfate content — which classify the site into the C1–C5 corrosion category framework. For a complete guide to classifying your site’s corrosion environment and specifying the correct protection level for the project design life, see our Corrosion Classes Guide for Ground Screws →

Solar Array Foundations (Case Studies)

Ground screws are now the dominant foundation type for solar ground-mount installations across the residential, commercial, and utility scale — across North America, Europe, Asia, and Australia. Representative applications include:

• Residential rooftop-supplementary ground mount (3–15 kW) — 6–20 piles of 60–76 mm OD × 900–1,200 mm embedment, hand-installed with walk-behind torque driver, same-day installation and panel mounting. See our Residential Solar Foundation guide →
• Commercial carport solar (100–500 kW) — 50–300 piles of 76–89 mm OD × 1,200–1,800 mm embedment, mini-excavator installation, single-day foundation programme for most sites, structural engineering sign-off via ICC-ES evaluation report or Eurocode 7 calculation
• Utility single-axis tracker (5–50 MW) — 1,500–15,000+ piles of 89–114 mm OD × 1,500–2,400 mm embedment, production rate 300–500 piles/day, pre-production ASTM D1143/D3689 load testing, torque monitoring records for 100% of production piles. See our Utility-Scale Solar Foundation Systems →
• Agrivoltaic solar (bifacial elevated arrays over crops) — extended embedment 2,000–3,000 mm to provide lateral stability for the elevated panel height required for equipment access below the array, with double-helix configuration in soft agricultural soil profiles

The Solar Power World utility solar ground screw analysis confirms that ground screws solve challenging site problems for utility-scale solar — including rocky soils, sloped terrain, and high-wind coastal sites where concrete drilling and curing logistics make conventional pier foundations impractical or uneconomical.

Deck and Patio Anchors

Residential and commercial deck foundation screws replace the concrete pad footings that are the conventional default for freestanding deck structures — providing frost-stable bearing from below the frost line (typically 600–1,200 mm below grade in temperate climates), an adjustable post height above grade to accommodate sloped terrain without step-footing complexity, and full code compliance with residential building codes that require foundations to penetrate below frost depth for structural stability. A typical residential deck on flat to moderate terrain requires 6–12 foundation piles of 60–76 mm OD at 1,000–1,500 mm embedment — installable in 2–4 hours with a compact torque driver or mini-excavator, versus the concrete alternative that requires excavation, form placement, reinforcing, concrete delivery scheduling, and 5–7 days minimum before the deck framing can begin. For elevated commercial decks and roof terraces on commercial buildings, our 89–114 mm OD deck foundation systems provide capacity for the higher tributary loads of commercial-occupancy decks. For product dimensions, height adjustment ranges, beam saddle specifications, and permit-ready connection details, see our Deck Foundation Screw Systems →

Fencing and Signage Support

Fence post ground screws and signage anchor screws share the same structural demand profile: they must resist lateral wind load on the fence panel or sign face — which acts as a sail and generates bending moments at the pile head — plus vertical self-weight, with no significant vertical compression demand. The dominant design check is therefore lateral bending capacity and passive soil resistance — confirming that the pile shaft’s section modulus is adequate for the maximum design bending moment, and that the pile embedment generates sufficient passive soil resistance to limit head deflection within the serviceability limit. For perimeter security fencing around solar farms, ground screw fence post anchors provide the added advantage of installation compatibility with the same equipment mobilised for the solar foundation programme — meaning that fencing and solar foundations can be installed as part of a single contractor mobilisation rather than requiring separate concrete fence post subcontractors. For temporary construction site fencing, ground screw anchors are the standard solution because they can be installed and removed repeatedly as site boundaries change during construction, without the concrete collar demolition required for temporary concrete fence posts. For post socket dimensions, panel rail connection options, and installation guidelines by soil type for fence post ground screws, see our Fence Post Ground Screw Anchors →

Greenhouse and Agricultural Structures

Commercial greenhouse and polytunnel foundations on agricultural land have a specific set of requirements that make ground screws the technically superior choice over concrete: the foundation must support wind uplift and lateral loads from the lightweight but large-area roof structure; the foundation must not impede the seasonal deep cultivation and drainage management operations that maintain soil productivity; and the foundation must be economically viable for the relatively low structural loads per foundation point of aluminium and steel greenhouse frame systems — making large concrete pad footings significantly over-engineered for the actual demand. Ground screw greenhouse foundations typically use 60–89 mm OD sections at 900–1,500 mm embedment, installed at 2–4 m spacing along the greenhouse eaves and ridge lines, with connection hardware compatible with the specific greenhouse manufacturer’s column base and anchor plate details. For agrivoltaic installations — where solar panels are mounted above active agricultural production — the ground screw foundation design must simultaneously satisfy the solar racking structural demand and provide adequate lateral resistance for the elevated panel height required to allow crop access below the array, without the concrete foundations that would impede agricultural equipment operation. For greenhouse frame connection details and product selection for agricultural structures, see our Greenhouse Ground Screw Foundation guide →

Diameter and Length Range Options

Extension sections (typically 1,000–1,500 mm) are available for all diameters, connected via bolted coupling sleeves that maintain full structural continuity for axial compression, tensile uplift, and lateral bending — enabling field-adjustable embedment depth to achieve the required installation torque criterion in variable soil conditions without pre-specifying the total pile length.

Helix Plate Sizes and Variants

The helix plate is the primary bearing element of the ground screw — its diameter determines the bearing area available for soil resistance, and its thickness determines its structural capacity under the bearing reaction force. Standard helix configurations in the Solar Earth Screw product range include:

All helix plates are formed from S355J2 or equivalent structural steel, hot-press formed to a true helical geometry (one pitch of a screw thread) — not a flat plate with a bent lip — confirming that the pile advances through soil by bearing displacement rather than auger excavation. Weld quality is certified to EN ISO 5817 Class B on all structural welds between the helix plate and the shaft, with weld procedure qualification records (WPQR) available to the project structural engineer on request. The Helical Pile World engineering guide confirms that typical helix sizes range from 8″ to 14″ diameter (200–355 mm) — the sizes in the above range cover this full span from the lightest residential to the heaviest utility application.

Recommended Torque and Installation Guidelines

Installation torque is both the primary installation control parameter and the real-time capacity verification tool for ground screw foundations — it is the value measured at the hydraulic torque head during installation that directly correlates to the pile’s load capacity via the empirical relationship Qu = Kt × T. The Helical Pile World torque factor reference confirms that for pipe shaft sections, the Kt factor typically ranges from 3 to 10 ft⁻¹ (approximately 10–33 m⁻¹), depending on the shaft diameter and soil type — with larger diameter shafts producing lower Kt values because of the greater soil disturbance during installation. Recommended minimum installation torque values by product series are published in the Solar Earth Screw installation manual and are derived from the product’s structural torsional yield capacity (the maximum torque the shaft can sustain without permanent deformation) and the required minimum pile capacity for the design load case. General installation guidelines:

• Installation rate — advance at approximately 25–50 mm per revolution, matching the helix pitch; faster advancement indicates auger-cutting behaviour rather than true helical penetration
• Torque monitoring — record torque at every 300 mm of depth, with the final installation torque calculated as the average of the last three helix diameter lengths (approximately 600–900 mm)
• Minimum torque criterion — every production pile must achieve the minimum final-section torque criterion specified in the project structural calculation — piles that do not achieve the criterion must be rejected and either driven deeper (if soil conditions improve) or replaced
• Verticality — piles must be installed within ±2° of vertical (or the specified rake angle for battered piles) to maintain the structural model assumed in the load calculation
• Obstruction protocol — when a pile contacts a sub-surface obstruction (cobble, root, buried concrete), the pile must be extracted and relocated — forcing past an obstruction by over-torquing causes shaft damage that is not detectable after installation

Galvanizing and Surface Protection Specifications

All Solar Earth Screw products are hot-dip galvanized as standard — the complete fabricated assembly (shaft, helix plates, coupling, and pile head hardware) is galvanized after all welding and fabrication operations are complete, per EN ISO 1461 requirements for post-fabrication galvanizing. Standard product coating specification: 85 µm mean zinc thickness, 70 µm minimum local thickness, compliant with EN ISO 1461 for steel section ≥ 6 mm. Enhanced coating options for C4 and C5 corrosion environments: 115 µm local minimum (reactive silicon-controlled steel, single-dip HDG); 215 µm local minimum (thick-coat specification using reactive steel and optimised bath chemistry). Duplex system (HDG + paint topcoat) is available for CX offshore and extreme industrial environments. Galvanizing test reports showing individual measurement results (not average only) are provided with every production batch — confirming compliance with the ISO 1461 thickness table for both mean and local minima on the specific production lot. For the complete galvanizing standard explanation — including how to specify the correct coating level for your site’s corrosion category, and what to verify on supplier test reports — see our Galvanizing Standards for Ground Screws →

What Sizes of Ground Screws Are Available?

Solar Earth Screw manufactures ground screws in shaft outer diameters from 48 mm (light residential and fence post) through 114.3 mm (heavy utility solar and infrastructure), with wall thicknesses from 3.0 mm to 8.0 mm and standard lengths from 600 mm to 3,000 mm plus extension sections. Helix plate diameters range from 150 mm to 300 mm, in single and double-helix configurations. For the vast majority of commercial solar applications, the 76–89 mm OD shaft with a 200–250 mm helix plate and 1,200–1,800 mm standard embedment covers the standard design demand envelope. For applications outside this range — unusually high loads, extreme embedment depth requirements, or non-standard helix configurations for specialist soil profiles — our technical team provides project-specific product selection support. Contact us with your structural load data and site soil investigation results and we will confirm the appropriate product specification for your project.

What Are Typical Load Capacities?

Typical load capacities for Solar Earth Screw products range from approximately 20–30 kN allowable axial load for the 48–60 mm residential range in standard C3 soil to 80–150 kN allowable axial load for the 89–114 mm utility range in dense sand or stiff clay, based on the standard torque correlation with Kt = 7 m⁻¹ and a factor of safety of 2.0 applied to the ultimate torque-derived capacity. These values are indicative only — the actual allowable load for any specific pile depends on the site soil conditions, the achieved installation torque, the corrosion protection specification, and the applicable design code. For utility solar projects, a pre-production load test programme per ASTM D1143 and D3689 is the recommended approach for confirming site-specific Kt factors and achieving the 2.0 factor of safety that ICC-ES AC358 allows with load test confirmation (versus the 3.0 factor required for calculation-only capacity). For a systematic explanation of how ground screw load capacity is calculated, how safety factors are applied, and how load testing confirms design capacity at the specific project site, see our Load Calculation Guide →

Can Ground Screws Be Reused or Removed?

Ground screws are fully removable and, depending on their condition after removal, potentially reusable — a key advantage over concrete foundations that cannot be economically removed and must be disposed of as construction waste. Removal is achieved by reversing the installation torque with the same hydraulic torque head used for installation — the pile unscrews from the soil using the helical plate geometry that guided its initial installation. Extraction is typically straightforward in standard soil conditions and takes a comparable time per pile as installation. After extraction, the pile condition determines reuse potential: piles with intact zinc coating (no section loss, no visible damage to the shaft or helix plate welds) can be cleaned, inspected, and reinstalled at a new location. Piles with zinc coating depletion in the buried zone should be inspected for section loss before reuse — residual wall thickness should be measured using ultrasonic thickness gauge testing at the historically most corrosive zone (the grade interface level) before the pile is structurally certified for reuse. For solar farm decommissioning at end of project life, the complete pile inventory can be extracted by the same installation contractor using the same equipment, leaving the site fully restored to its original condition — a material advantage for solar farm lease terms that include reinstatement obligations to the landowner.

Engineering-Driven Manufacturing Quality

Solar Earth Screw products are manufactured to engineering-specified tolerances — not to approximate commercial standards — because the structural engineer’s load capacity calculation depends on the pile section dimensions, material grade, and weld quality being within defined limits. Every production batch begins with incoming steel inspection against EN 10204 Type 3.1 mill test certificates confirming S355J2 grade mechanical properties and chemical composition; proceeds through fabrication with dimensional control on shaft diameter, wall thickness, and helix pitch; and concludes with hot-dip galvanizing to EN ISO 1461 with batch test report documentation confirming individual measurement compliance — not just a blanket declaration of ISO compliance. Weld quality on all structural welds (helix plate to shaft, coupling to shaft, and pile head to shaft) is performed to qualified weld procedures per EN ISO 15614-1, with weld records maintained in the production quality management system. For a detailed overview of the manufacturing facility, production quality control programme, and equipment capabilities, see our Factory Overview →

Compliance With International Standards

Solar Earth Screw products are designed and manufactured to comply with the full range of international standards relevant to structural ground screw foundation systems — covering material certification (EN 10025 / ASTM A500), hot-dip galvanizing (EN ISO 1461 / ASTM A123), corrosion protection classification (EN ISO 9223/9224), structural design (Eurocode 3 / AISC 360), and geotechnical load design (Eurocode 7 / IBC Section 1810 / ICC-ES AC358). This multi-standard compliance framework means that Solar Earth Screw products can be specified on projects governed by either European or North American engineering codes, and that the complete documentation package — material test certificates, galvanizing test reports, structural calculation packages, and load test reports — can be provided to the project’s structural engineer and independent engineer in the format required for any major jurisdiction’s permitting and project finance due diligence process. The comprehensive engineering compliance framework covering material standards, galvanizing specifications, corrosion protection requirements, and structural load design codes is described in our Ground Screw & Solar Foundation Standards Guide →

Global Support and Technical Documentation

Ground screw foundation design is an engineering-intensive process — it requires site-specific soil investigation data, project-specific structural load calculations, a pre-production load testing programme, and a production installation torque monitoring programme that together form the compliance evidence package required for permitting, project finance, and structural sign-off. Solar Earth Screw provides comprehensive technical support across the full project delivery cycle: pre-bid product selection and preliminary load capacity estimation from preliminary soil data; design stage structural calculation review and torque criterion recommendation; load testing specification and results interpretation; and post-installation quality documentation compilation. Our technical documentation library includes detailed installation manuals, connection detail drawings, structural calculation templates for common solar racking configurations, and galvanizing specification guides for each corrosion category — all available for download and for submission to project structural engineers as basis-of-design documentation. For projects requiring site-specific technical support, load calculation review, or material compliance documentation packages, our engineering team provides direct technical assistance. Contact us to discuss your project’s specific engineering requirements.

Download the Product Catalog

Our full product catalog provides complete dimensional tables, weight and zinc coating data, standard load capacity tables by product series and soil category, compatible connection hardware dimensions, and installation equipment compatibility specifications for the complete Solar Earth Screw ground screw product range. The catalog is produced in PDF format for direct use in project tender documentation, contractor specification packages, and engineering design submissions. Download the latest edition below — current edition includes the complete 48–114 mm shaft range, all standard helix configurations, and the full enhanced galvanizing specification options for C4 and C5 corrosion environments.

Download the Solar Earth Screw Product Catalog →

Request Technical Drawings and Engineering Specifications

Engineers, EPC contractors, and project developers requiring CAD drawings, structural section properties tables, pile head connection detail drawings, or EN 10204 Type 3.1 material certificates for their specific product specification can request these documents directly from our technical team. Standard documentation available on request includes: AutoCAD DWG and PDF format assembly and detail drawings for all standard product configurations; section properties tables (area, section modulus, moment of inertia, torsional constant) for all shaft sizes; EN ISO 1461 galvanizing specification sheets for standard and enhanced coating options; and EN 10025 S355J2 material grade specification confirming the grade’s mechanical property and chemical composition requirements.

Request Technical Drawings and Specifications →

Get a Project-Specific Product Recommendation

If you have site soil investigation data, structural load requirements, and project location information — or if you are at the early stage of a project and need guidance on what site investigation and structural design data is required before product selection can be finalised — our technical team can provide a project-specific product recommendation within 2–5 business days. Provide us with: project location and site description; preliminary soil investigation data (SPT N values, soil descriptions, groundwater depth); structural demand per pile (design axial compression, uplift, and lateral load from the racking or structural engineer); applicable loading code (ASCE 7-22, Eurocode 1, or national equivalent); and design life requirement. We will confirm the recommended product specification, indicative load capacity, minimum installation torque criterion, galvanizing specification for the site corrosion class, and required load testing programme — giving you the information needed to complete the foundation specification and proceed to procurement.

Submit a Project Enquiry and Get a Technical Recommendation →