Solar Panels for Farm Buildings: Barns, Sheds and Grain Stores

Farm buildings represent the single biggest untapped opportunity for agricultural solar in the UK. Barns, machinery sheds, grain stores, and livestock housing collectively offer millions of square metres of south-facing roof space that could be generating clean, free electricity for the businesses that operate beneath them. Yet many farmers remain uncertain about whether their buildings are suitable, what the process involves, and what it will cost. This guide answers every question we hear from farmers considering solar panels on their agricultural buildings.

The economics are compelling. A well-designed solar installation on a farm building can cut electricity bills and generate income through the Smart Export Guarantee; payback depends on how much of the output the farm uses itself. The key is understanding which buildings are suitable, what preparation is required, and how to navigate the planning and structural considerations specific to agricultural properties.

Whether you are looking at a modern portal frame machinery shed, a traditional timber barn, a steel-clad grain store, or a concrete livestock building, the principles and process are broadly similar — but the details matter. This guide walks you through every stage, from initial assessment to completed installation. For a broader overview of solar across all agricultural building types, see our main solar panels for agricultural buildings page.

Which Farm Buildings Are Suitable for Solar Panels?

Almost any farm building with a sound roof and adequate structural capacity can accommodate solar panels. However, some building types are better suited than others, and understanding these differences at the outset saves time, money, and frustration.

Portal Frame Steel Buildings

Portal frame buildings are the most common modern agricultural structure in the UK and are generally the easiest and most cost-effective to retrofit with solar panels. These buildings feature a rigid steel frame with purlins supporting profiled metal cladding, and the mounting method depends on the sheet — box-profile, corrugated or standing seam (solar on metal-clad farm buildings). The structural strength of the frame typically exceeds what is needed for the cladding alone, providing spare capacity for solar panels.

A standard portal frame machinery shed or grain store built after 1990 will usually support a solar array without structural modification. The key factors are the purlin spacing (typically 1.2-1.8 metres), the gauge and condition of the roof cladding, and the overall condition of the steelwork. Systems are fixed to the purlins using bracket clamps that do not penetrate the roof sheet, maintaining the building’s weatherproofing.

Portal frame buildings commonly seen on arable farms and mixed holdings offer large, unobstructed roof areas — often 500-2,000 square metres — making them ideal for systems of 50kW to 250kW or more. A 1,000 square metre south-facing roof can typically accommodate a 100-120kW system generating 95,000-115,000 kWh per year.

Traditional Timber-Framed Barns

Older timber-framed barns require more careful assessment. The structural capacity of timber trusses varies enormously depending on the species, age, and condition of the wood, the span of the trusses, and the original design loading. A structural engineer experienced in agricultural buildings can assess whether the existing timberwork will support panels or whether reinforcement is needed.

Reinforcement, where required, typically involves adding steel plates, additional purlins, or supplementary steel beams. This adds cost — typically £2,000-£8,000 depending on the extent of work — but rarely makes a project unviable. Many listed or traditional barns have been successfully retrofitted with solar panels following appropriate structural upgrades.

Grain Stores and Drying Facilities

Grain stores are among the best candidates for solar on any farm. The energy demand for grain drying — which can consume 50,000-150,000 kWh in a single harvest season — coincides with peak solar generation months (July-September). A well-sized solar system with battery storage can offset a substantial proportion of drying costs.

Modern flat-roofed grain stores can use ballasted mounting systems that require no roof penetrations, while pitched-roof stores use standard purlin-mounted systems. The key consideration is access: grain stores are typically filled from above using conveyors or augers, so panel layouts must leave clear zones for loading access. Experienced agricultural installers design around these operational requirements as a matter of course.

Livestock Housing

Livestock buildings — including dairy housing, beef cattle sheds, and poultry units — present specific considerations. Ventilation requirements mean these buildings often have open sides or ridge vents that affect panel layout. Ammonia and moisture levels inside livestock buildings can accelerate corrosion of underside fixings if not properly specified.

Poultry houses are particularly strong candidates for solar. A typical 20,000-bird broiler unit has a roof area of 2,000-3,000 square metres and constant electricity demand for ventilation, lighting, and feeding systems. A 150-250kW solar system can significantly offset these running costs. Dairy buildings similarly benefit from solar, with milking parlour, bulk tank cooling, and water heating loads all well-matched to solar generation profiles.

Machinery Sheds and Workshops

Open-fronted machinery sheds and enclosed farm workshops are typically straightforward installations. These buildings usually have robust steel frames, large unshaded roof areas, and no internal environment constraints. The main consideration is the building’s orientation — due south is ideal, but east-west orientations still generate 85-90% of the theoretical maximum output with the right panel configuration.

The Structural Survey: What It Involves and Why It Matters

Every agricultural solar installation begins with a structural survey. This is not optional — it is a requirement of both MCS certification standards and building regulations. A competent surveyor will assess roof condition and remaining useful life, structural frame capacity and load paths, purlin size, spacing, and condition, cladding type, gauge, and fixing condition, foundation adequacy, and wind and snow loading calculations for the specific location.

For a detailed walkthrough of the full assessment process, our dedicated barn roof assessment guide covers every stage from initial inspection through to structural sign-off.

The survey typically costs £500-£1,500 depending on the size and complexity of the building. Many specialist agricultural solar installers include the structural survey in their overall project quotation. The survey report informs the system design, identifying exactly which roof areas can carry panels, where additional fixings or reinforcement may be needed, and any remedial work required before installation can proceed.

Worth reading alongside this: whether your barn roof will carry it.

The Asbestos Question

Asbestos cement roofing remains widespread on UK farm buildings built before the 1999 ban on asbestos. This is one of the most important issues to address early in any agricultural solar project: HSE says asbestos cement roofs are always fragile and cannot bear weight, so panels are never fixed straight onto them. Our guide to fitting solar to an asbestos cement roof sets out the routes and the legal duties.

Solar panels cannot be mounted directly onto asbestos cement sheets. The material is brittle, it cannot support bracket clamps, and drilling into it releases hazardous fibres. There are two approaches to dealing with asbestos roofs:

• Over-roofing: A new profiled steel roof is installed over the existing asbestos sheets using a secondary purlin system. Solar panels are then mounted on the new steel roof. This approach avoids the cost and disruption of asbestos removal and is often the most cost-effective solution.

• Removal and re-roofing: The asbestos sheets are removed and replaced with new profiled steel cladding. HSE treats small-scale removal of intact sheets as normally non-licensed work, but a whole roof needs a full risk assessment and plan of work. This costs more than overcladding but provides a completely new roof with a fresh lifespan. Some farmers choose this route if the underlying steelwork also needs refurbishment.

Both approaches are well-established in agricultural practice. An experienced installer will advise on the most appropriate route for your specific buildings. The key message is that asbestos roofing does not rule out solar — it simply requires an additional step in the process.

Planning Permission for Solar on Farm Buildings

In England, solar panels on agricultural buildings generally benefit from permitted development rights under Class J of Part 14 of the General Permitted Development Order. This means planning permission is not required provided the panels protrude no more than 200mm from a pitched roof plane (or sit no more than 1 m above the highest part of a flat roof) and are at least 1 m from the roof edge. There is no capacity limit, but above 50 kW the council’s prior approval is needed on design and appearance (glare). In a conservation area, National Park, National Landscape (AONB) or World Heritage Site, the only extra restriction is on panels fixed to a wall that fronts a highway — roof panels are not restricted there.

Where permitted development conditions are not met, a full planning application is required. This is a straightforward process for roof-mounted systems. The fee depends on the type of application and the site area; the Planning Portal’s fee calculator gives the current figure.

Listed buildings, buildings within their curtilage and scheduled monuments are excluded from permitted development, so they need planning permission — and listed buildings also need listed building consent. This is increasingly granted for sensitively designed installations — particularly on secondary or modern agricultural buildings within the listed curtilage — but requires specialist planning advice.

Our installation process page provides a step-by-step guide to the full planning and installation journey for farm solar projects.

Costs by Building Type

Agricultural solar installation costs vary depending on system size, building type, roof condition, and the extent of any preparatory work required. The only official benchmark is the DESNZ 2025/26 median installed price of about £1,262 per kW for 10–50 kW systems (Great Britain; including VAT where charged; excluding batteries). There is no official series above 50 kW, so larger arrays are priced from itemised quotes.

Battery storage, if added, is not included in the DESNZ figure. For a detailed cost breakdown and to calculate potential savings for your specific farm, visit our pricing page or use the farm solar cost calculator.

Check the current position on agricultural solar grants before counting on one: no grant for solar panels on farms is open in England, and no Welsh, Scottish or Northern Ireland grant pays for them. Round 2 of the Improving Farm Productivity grant paid up to 25% of eligible costs for rooftop solar but has closed (full applications closed 31 July 2025); the Farming Equipment and Technology Fund’s 2023–2026 item lists did not include solar panels to power a farm, and Capital Grants 2026 have no solar items. Most farms can instead deduct the whole cost in year one through the £1 million Annual Investment Allowance (a partnership with a company as a member cannot claim it).

Installation Process for Farm Buildings

The typical installation process for solar panels on a farm building follows a well-established sequence. Each of these stages is explained in the solar panel installation service guide:

• Initial site assessment (Week 1-2): A specialist assessor visits to inspect roof condition, measure available area, assess structural capacity, check electrical infrastructure, and discuss your energy usage patterns.

• Structural survey (Week 2-4): A qualified structural engineer surveys the building and produces a report confirming suitability or specifying any required reinforcement works.

• System design and quotation (Week 3-5): The installer produces a detailed design, energy yield estimate, and financial projection including available grants and finance options.

• Planning and grid application (Week 4-8): If required, planning permission is applied for. A G99 grid connection application is submitted to the Distribution Network Operator. For larger systems, this can take 8-12 weeks for approval.

• Preparatory works (Week 6-10): Any structural reinforcement, over-roofing, or electrical upgrade works are completed.

• Installation (Week 8-14): The panel array, inverters, and electrical systems are installed. A typical 100kW farm building installation takes 5-8 working days on-site.

• Commissioning and MCS registration (Week 10-16): The system is tested, commissioned, and registered with MCS, which Smart Export Guarantee suppliers require for systems up to 50 kW.

The total process from initial enquiry to commissioned system typically takes 10-16 weeks, depending on planning requirements and DNO connection timescales.

Maximising Return on Investment

The financial return from solar panels on farm buildings depends on three key factors: the proportion of generated electricity consumed on-site (self-consumption), the export tariff received for surplus electricity, and any grant support received.

Self-consumption is by far the most important factor. Every kilowatt-hour consumed on-site saves the full retail electricity price (your full unit rate), whereas exported electricity earns only the Smart Export Guarantee rate (each licensed supplier sets its own rate). Battery storage increases self-consumption by storing daytime solar generation for use during evening, overnight, and early morning demand periods.

For a complete breakdown of costs, returns, and payback timelines, see our pricing guide and grants page. Farmers on arable holdings, dairy units, and poultry operations will find farm-type-specific guidance on these pages.

Frequently Asked Questions

Can I install solar panels on a barn with an asbestos roof?

Yes, but not directly on the asbestos sheets. The two options are over-roofing (installing a new steel roof over the asbestos) or removal and replacement. Both are well-established approaches. Overcladding avoids the disturbance and waste of stripping the old roof, but leaves the asbestos in place, where it must still be managed.

Do I need planning permission for solar panels on a farm building?

In most cases, solar panels on agricultural buildings benefit from permitted development rights and do not require planning permission. In England, the exceptions are listed buildings, buildings within their curtilage and scheduled monuments; in conservation areas, National Parks and National Landscapes (AONBs), only panels fixed to a wall that fronts a highway are restricted, not roof panels. Your installer will confirm the planning position as part of the initial assessment.

How long do solar panels on farm buildings last?

Modern solar panels carry 25-30 year performance warranties and are expected to continue generating electricity for 35-40 years. Inverters typically have a 10-15 year lifespan and may need replacing once during the system’s life. The mounting systems used on agricultural buildings are engineered for the same lifespan as the panels.

Will solar panels damage my barn roof?

When installed correctly by a qualified agricultural installer, solar panels should not damage the roof. Standing-seam roofs can take clamps that do not penetrate the sheets; on profiled-sheet roofs the brackets or rails are fixed through the sheets with sealed fixings, so ask for a mounting kit certified to MCS 012. The structural survey conducted before installation ensures the building can safely support the additional load.

Can I install solar on an open-sided building?

Yes, open-sided buildings such as machinery stores and hay barns can be fitted with solar panels. The key consideration is wind loading — open-sided buildings experience different wind uplift forces compared to enclosed structures, which must be accounted for in the structural calculations and mounting system design. Your structural surveyor will factor this into the assessment.

Ready to explore solar panels for your farm buildings? Contact Solar Panels For Farms UK for a free initial assessment. Solar Panels For Farms UK is an independent guide, not an installer: your enquiry goes to a matched MCS-certified installer covering your area, which returns a desk feasibility within 3 working days.

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