Ground-Mounted Solar Installation

When the ground beats the roof

If your roof is shaded, north-facing, thatched, structurally tired — or you own a paddock or a large garden and would rather leave the house alone — a ground-mounted array is the installation type that stops compromising. Freed from whatever tilt and orientation the roof happens to offer, ground-mounted panels sit at the ideal angle of roughly 35 degrees facing due south, and deliver the best yield per kWp of any mounting method: a domestic or paddock-scale system of 4–12 kWp typically generates 3,600–11,000 kWh a year.

The trade-offs are equally concrete. Frames, groundworks and cable trenching push the installed price to £7,000–£16,000 — above an equivalent roof array — and the planning position is tighter than for roof solar, with permitted development capped at a 9 m² array. Payback still models around nine years for most systems, because the superior yield partially claws back the extra capital. This page covers how a ground-mount is actually built, why the cable run is the line most quotes underprice, and where the planning boundaries sit.

Building a ground-mount from the ground up

A ground-mounted installation is a small civil-engineering job followed by an electrical one. No scaffold, no roofers — instead: setting out, foundations, frames, and a trench.

Survey: ground, route and grid

The survey walks the site rather than the loft. It fixes the array position for sun and shading across the year (a fence line or hedge that is harmless in June can wipe out winter output), assesses the ground itself — soil type, slope, drainage, buried services — and, critically, walks the cable route from array to consumer unit, measuring the real distance including every bend and obstacle. The consumer-unit check and grid-connection assessment are identical to any solar job: spare ways, earthing arrangement, and whether the system falls under G98 or needs a G99 application to the District Network Operator before energisation.

Foundations: concrete or ground screws

Two foundation methods dominate. Concrete foundations — pads or strip footings — suit smaller arrays and poor ground, but need excavation, shuttering, pours and cure time, adding days to the programme. Ground screws — large steel screws driven by machine — install in hours, work in most soils, disturb the ground far less and can be removed cleanly later, which is why they have become the default for paddock-scale work; rocky ground or very soft soil sends the design back toward concrete or engineered posts. Either way, the foundation layout is set out to the frame manufacturer’s grid, checked for level and line before frames go on. A ground-mount that racks out of square over its first winter is a foundations failure, and it is the hardest fault to correct after the fact.

Frames and panels

The galvanised steel or aluminium frames bolt to the foundations, building a tilted table at around 35 degrees facing south — or the site’s best available compromise. Panels clamp on in landscape or portrait rows, DC connectors clicking together as on any array, with cabling secured along the frame rather than left to flex in wind. At ground level the work is faster and safer than roof work: no working-at-height constraints, no tile handling, and maintenance access forever after is from a standing position — no scaffold ever again. The counterpart is exposure of a different kind: panels at ground level are reachable by people as well as owners, so fencing, sightlines and inverter siting deserve real thought — an inverter in a locked outbuilding beats one bolted to the back of the frame in an open field.

The trench: the messiest day of the job

The array connects back to the house through an armoured (SWA) cable, and the trench that carries it is the hidden cost line of ground-mounted solar. The cable is buried at a safe depth — through lawn, beds, drives and whatever else lies between the array and the consumer unit — with warning tape above it, then backfilled and reinstated. Expect the trench day to be the messiest of the project, and useful to know in advance if the route crosses a prized lawn or a gravel drive that will need making good.

Distance is the technical trap. Long cable runs lose voltage, and the fix is thicker cable: runs beyond a few tens of metres frequently need upsizing to control voltage drop, and on a 100-metre paddock run the cable and trenching can become one of the largest single lines in the quote. A quote priced from a guessed distance, without the route walked and measured, is the classic source of on-the-day extras in this install type. Ask what cable size the voltage-drop calculation produced — an installer who has actually done the calculation will answer without hesitation.

Commissioning and handover

The electrician terminates the SWA at both ends, fits isolators at the array and the house, connects into the consumer unit and commissions: insulation-resistance and polarity tests, inverter configuration, monitoring walkthrough. Commissioning at ground level is also the moment to record the system’s baseline — a photograph set of the finished frames, foundations and cable terminations, the inverter’s commissioning readings, and the first weeks of monitoring data give you the reference against which any future fault stands out immediately. Ask for the monitoring walkthrough to cover what winter output should look like: a 35-degree array sheds snow faster than a shallow roof system, but short December days still surprise first-year owners, and knowing the normal seasonal shape stops false alarms. Handover paperwork is the standard MCS set — MCS certificate, Electrical Installation Certificate, DNO notification or G99 approval evidence, warranty registrations — plus, sensibly, a drawing of the buried cable route for whoever digs in that garden next.

Sizing, cost and why payback holds up

Sizing starts from consumption, exactly as for roof systems: a home using 3,500–4,500 kWh a year is well served by 4–5 kWp, while an EV, a heat pump or workshop loads justify pushing toward 8–12 kWp — and on the ground, unlike a roof, the space constraint rarely bites first. With 440–475 W panels, 9–27 panels covers the domestic and paddock range, occupying 25–70 m² of ground plus access around it.

On cost, £7,000–£16,000 covers most domestic and paddock-scale installations. Against the MCS-reported England roof-average of roughly £1,565–£1,590 per kW (as at spring 2026), the ground-mount premium buys foundations, frames, groundworks and the cable run — and pays some of itself back through yield, since ideal tilt and orientation put more kWh behind every installed kW than all but the best roofs. Payback models around nine years for typical systems. Domestic installations take 0% VAT until 31 March 2027 (then 5%), and exported units earn Smart Export Guarantee rates of roughly 12–16p/kWh on leading tariffs as at mid-2026, against an import price around 26p for units you use yourself — which is why a battery pairs well with a generously-sized ground array; the solar battery installation page covers coupling and siting. The full price table is on the cost guide, and export and VAT detail under grants and funding routes.

The 9 m² rule: planning for ground arrays

Ground-mounted solar has its own, tighter permitted-development category, and the numbers catch people out. Under GPDO Part 14 Class B, a domestic standalone array is permitted development only up to 9 m² of array area and 4 m in height (with siting conditions besides). Nine square metres is roughly four modern panels — perhaps 1.8 kWp — so any ground-mount sized to run a household exceeds the limit and needs a planning application. That is not a prohibition: householder applications for well-sited garden and paddock arrays are commonly approved, but the application takes weeks, costs a fee, and belongs at the start of the programme, not after the frames arrive. Listed settings and designated land carry additional constraints, and the England-only caveat applies — Scotland and Wales run separate regimes.

Agricultural and commercial ground arrays are a planning matter at any meaningful scale, with their own considerations around land classification and landscape impact. On the electrical side nothing changes with mounting: the work is notifiable under Part P where it serves a dwelling, executed to BS 7671, and grid connection follows G98 up to 16 A per phase (about 3.68 kW of inverter) or a G99 application — approved before energisation — above it. Most ground-mounts sized to justify their groundworks sit in G99 territory, so the application belongs at survey stage.

Worked scenario: a 10 kWp paddock array

A scenario modelled from the ranges above, not a client project. A rural property with a heavily-shaded roof and a paddock beside the drive wants to cover a 9,000 kWh annual consumption that includes an EV. The design: 22 × 455 W panels (10 kWp) on two ground-screw-founded frame rows at 35 degrees due south, sited behind the existing hedge line to keep the array out of the main view — a siting choice that also smooths the planning application, which the 40 m² array requires, being well past the 9 m² Class B limit. The application is submitted at survey stage and approved in seven weeks.

Ground screws go in over a day; frames and panels take two more. The cable route back to the house measures 60 m, and the voltage-drop calculation upsizes the SWA accordingly — cable and trenching account for a four-figure line in the £14,000–£15,500 total, which is exactly the line a route-unmeasured quote would have missed. G99 approval, obtained before energisation, permits full export. Modelled generation is around 9,800 kWh a year; with the EV charging shifted to daytime and surplus exported at current dated SEG rates, the annual benefit models at £1,500–£1,800 and payback just under nine years. No scaffold was hired, and none ever will be — panel cleaning and any future inverter swap happen from the ground.

Ground-mount questions answered

Do I need planning permission for a ground-mounted array?

Above 9 m² of array area — about four modern panels — yes, in England: Class B permitted development stops there, and it also caps height at 4 m. Practically, any system sized to power a household needs a householder planning application, which is routinely achievable with sensible siting but takes weeks and belongs at the start of the project. Scotland and Wales have their own rules.

Is ground-mounted solar more expensive than roof solar?

Per installed kW, usually yes — £7,000–£16,000 for typical systems, with foundations, frames and the cable trench accounting for the premium over a comparable roof array. Per generated kWh the gap narrows or disappears: ideal tilt and orientation give ground-mounts the best yield per kWp of any mounting, which is why payback still models around nine years.

How disruptive is the installation?

The trench is the honest answer. Foundations and frames confine themselves to the array area, but the SWA cable trench crosses everything between array and consumer unit and its excavation is the messiest day of the job. Agree the route, depth, reinstatement and who makes good the lawn or drive in writing before work starts.

How far can the array be from the house?

There is no hard limit, but distance costs copper: voltage drop over long runs forces thicker cable, and beyond roughly 50–100 m the cable and trenching become a major cost line. The route should be walked and measured at survey, and the cable size justified by a voltage-drop calculation — ask for the number.

What about security and theft?

Ground-level access cuts both ways: maintenance never needs scaffold again, but panels and especially inverters are reachable. Sensible mitigations are siting the inverter in a locked outbuilding rather than on the frame, stock fencing where animals graze nearby, and keeping the array out of direct sightlines from the road. None of this is exotic — it is the same thinking applied to any valuable garden asset.

Related pages

If the building has usable flat roof space, a flat roof solar installation keeps the array off the ground without touching a pitched elevation. A generously-sized ground array pairs naturally with storage — the solar battery installation page covers DC versus AC coupling, PAS 63100 siting and the G99 sequence. Then see typical costs and payback, check available grants, or get a free quote with the cable route measured, not guessed.