Ground-mount PV systems: structures and foundations
A ground-mount PV system is a free-standing frame of galvanised steel and aluminium that holds modules at a fixed tilt, usually around 20 to 35 degrees, on foundations driven or cast into the ground rather than fixed to a building. Because it is not limited by a roof, a ground array can be oriented and tilted for maximum yield and scaled from a garden installation to a solar farm. This guide covers the structure, the foundation options, the tilt and row spacing, and how Eurocode wind and snow loads size the frame. For rooftop systems see our guide to PV roof mounting components.
What a ground-mount system is
A ground-mount structure is a row of inclined tables standing on foundations. Vertical posts carry raking beams that set the tilt, and horizontal purlins or rails across those beams hold the modules. The frame does the same job as a roof mounting, transferring the module weight and the wind and snow loads into the ground, but it also has to stand up on its own rather than borrowing a roof for support. ULAMEX supplies the structural components, the aluminium rails and clamps and the galvanised steel sub-structure, not the modules or the electrical parts.
The structure: steel and aluminium
Ground arrays use each metal for what it does best. The load-bearing sub-structure, the posts and beams, is usually galvanised steel, because steel is stiff and economical and carries the wind and snow load of a large table on slim sections. The module rails and clamps are aluminium, EN AW-6060 T6, because they sit at the exposed surface and must not corrode. This mix of a galvanised steel frame carrying aluminium rails gives a long-lived structure at a sensible cost. For the steel side see our guide to galvanised steel and DX51D.
Foundations: rammed piles
The most common foundation is a rammed, or driven, pile. A galvanised steel section, often a C or U profile, is driven straight into the ground by a pile driver to a depth set by the ground and the load, with no digging and no concrete, so a foundation is placed in minutes. Rammed piles suit most soils, are quick over a large site, and can be pulled and reused if the array is ever moved. The pile is hot-dip galvanised or Magnelis-coated for a corrosion life to match the twenty-five-year-plus array, which is why the foundation needs no maintenance once driven.
Foundations: ground screws and concrete
Where a rammed pile will not hold, other foundations take over. A ground screw is wound into the soil like a giant screw, giving a firm anchor in loose or mixed ground without concrete. A concrete foundation, either a cast footing or a precast block, is used in rock, in made ground, or where the pull-out load is very high. On hard standing and some commercial sites a ballasted frame sits on concrete blocks without any penetration at all. The foundation is chosen from the ground conditions and the calculated load, which is why a soil survey comes before the design.
Tilt angle and orientation
Free of a roof, a ground array is set to the angle that gives the best yield. In continental Europe a fixed tilt of roughly 20 to 35 degrees facing the equator is typical, steeper toward the north of the region and shallower toward the south. Where ground is limited, an east-west layout with two module faces per table packs more capacity onto the same land at a lower tilt. The structure is built to hold whichever angle the design calls for, and the tilt in turn drives the wind load and the spacing of the rows.
Row spacing and shading
Rows have to be spaced so that one table does not shade the next in low winter sun. The gap, called the pitch, is worked out from the tilt, the table height and the sun angle at the site, so a steeper tilt and a higher latitude both push the rows further apart. Getting the pitch right trades land against yield: too tight and the array loses winter output to shading, too wide and it wastes ground. The structure and the foundation layout follow from this row plan, which is set at the design stage for the specific site. Because the pitch decides how much land a given capacity needs, it feeds straight into the economics of the plant, balancing the cost of ground against the value of the winter yield that wider spacing preserves.
Wind and snow loading
A ground array presents a large tilted surface to the wind, so the loads are calculated to the Eurocode, EN 1991-1-4 for wind and EN 1991-1-3 for snow, for the exact location. Wind can both push on the front of the tables and lift them from behind, and an exposed open site carries far more wind than a sheltered one, so the post size, the bracing and the foundation depth all follow the calculation. Snow adds a downward load that matters in continental and mountain regions. Sizing the structure to the real loads is what keeps a field of tables standing through storms and winters.
Certification and durability
A ground-mount structure is a load-bearing steel and aluminium construction, so its structural components are CE-marked and ULAMEX manufactures under EN 1090. The galvanised steel and the aluminium are both chosen for a service life of twenty-five years and more in the open, matching the design life of the modules they carry. Because the structure outlasts several changes of inverter and cabling, building it in the right metals from the start, rather than saving a little on coating, is what avoids a costly rebuild halfway through the life of the plant.
Site preparation and layout
A ground array starts with the ground, so the site is surveyed before the structure is designed. A soil investigation shows what foundation the ground will take, whether a rammed pile holds or a screw or concrete footing is needed, and a level survey sets out how the rows sit across a sloping or uneven field. Access routes for the pile driver and for delivery are planned, and the drainage of the site is considered so water does not undermine the foundations. Getting the survey and the layout right first means the structure is designed to the real site, not to an assumption, which avoids costly changes once the piles are going in.
Maintenance access between the rows
A ground array is walked and driven for its whole life, so the layout leaves room to maintain it. The gaps between rows, set for shading, also give access for cleaning, inspection and any module change, and the structure is high enough at its lower edge to keep the modules clear of splashing soil and growing vegetation. Keeping the ground beneath managed, with vegetation cut back and drainage clear, protects both the output and the foundations. Designing this access in from the start, rather than packing the rows as tight as shading allows, is what keeps a large array serviceable over twenty-five years and more.
Fixed tilt and trackers
Most ground arrays are fixed-tilt: the tables are set to one angle and do not move, which is simple, robust and cheap to run, and it is the structure the great majority of installations use. A tracker structure instead turns the modules to follow the sun across the day, lifting yield but adding motors, controls and moving joints that need their own maintenance and raise the cost and the failure points. The choice between them is an engineering and commercial one for each project, weighed against the site, the land value and the tariff. ULAMEX supplies the fixed-tilt structure, the galvanised steel frame and the aluminium rails and clamps that carry the modules, which suits the continental installations where simplicity and low maintenance matter more than the last few percent of yield.
From a garden array to a solar farm
The same components scale across very different projects. A small free-standing array in a garden or on a smallholding uses a few tables on rammed piles. A commercial installation on a field or a brownfield site runs to hundreds of tables in long rows. An agrivoltaic layout raises the tables or turns them vertical so a crop can grow beneath or between them. In every case the engineering is the same, scaled to the site: galvanised steel foundations and frame, aluminium rails and clamps, sized to the ground and the Eurocode loads.
Ground-mount components from ULAMEX
ULAMEX manufactures PV mounting components under EN 1090 and has supplied the trade since 1988.
| Component | Detail |
|---|---|
| Sub-structure | Galvanised steel posts and beams, hot-dip or Magnelis-coated |
| Rails and clamps | EN AW-6060 T6 aluminium rails, mid and end clamps 30 to 50 mm |
| Foundations | Rammed pile profiles, ground screws or ballast to suit the ground |
| Hardware | T-bolts, sliding nuts, connectors, stainless fasteners, earthing |
| Certification | Structural components under EN 1090; corrosion life 25 years and more |
| Terms | No minimum order on stocked SKUs, dispatch 2 to 7 working days, Europe-wide delivery from Poland |
Planning a ground array? Send the layout, module count, tilt and site conditions, and ULAMEX will return a non-binding quotation with lead time and availability. Browse the photovoltaic mounting range, read the full PV mounting systems guide, or view our supply capabilities. Contact the export desk at [email protected] or +48 504 424 761.
Frequently asked questions
What is a ground-mount PV structure made of?
The load-bearing sub-structure, the posts and beams, is usually galvanised steel because it is stiff and economical. The module rails and clamps are EN AW-6060 T6 aluminium because they sit at the exposed surface and must not corrode. This mix of a galvanised steel frame carrying aluminium rails gives a long-lived structure at a sensible cost.
What foundation does a ground array use?
Most commonly a rammed, or driven, pile: a galvanised steel section driven into the ground with no digging or concrete, placed in minutes. Ground screws suit loose or mixed soil, and cast or precast concrete is used in rock, made ground or where pull-out loads are high. The choice comes from a soil survey and the calculated load.
What tilt angle is used?
In continental Europe a fixed tilt of roughly 20 to 35 degrees facing the equator is typical, steeper toward the north of the region and shallower toward the south. Where ground is limited, an east-west layout at a lower tilt packs more capacity onto the same land. The structure is built to hold whichever angle the design calls for.
How far apart are the rows?
The row pitch is worked out from the tilt, the table height and the sun angle at the site, so a steeper tilt and a higher latitude push the rows further apart to avoid one table shading the next in low winter sun. It trades land against yield and is set at the design stage for the specific location.
How is a ground array sized for wind and snow?
To the Eurocode, EN 1991-1-4 for wind and EN 1991-1-3 for snow, for the exact site. Wind both pushes on and lifts the tilted tables, and an exposed site carries far more than a sheltered one, so the post size, bracing and foundation depth follow the calculation. Snow adds a downward load in continental and mountain regions.
Does ULAMEX supply the whole system?
ULAMEX supplies the mounting structure: the galvanised steel sub-structure and foundations, the aluminium rails and clamps, and the fasteners, all under EN 1090. The modules, inverters, cabling and electrical work are handled by the installer. Send the layout, module count and site conditions and the export desk will quote the structure.