Farm Building Roof Suitability for Solar Panels

Is Your Farm Building Roof Suitable for Solar Panels?

The suitability of your farm building roof is the single most important factor in determining whether a solar panel installation is feasible, how much it will cost, and how much electricity it will generate. UK farms feature a wide variety of building types and roof coverings, from modern portal frame steel structures with box profile sheeting to century-old stone barns with slate roofs and everything in between.

Each roof type presents its own opportunities and challenges for solar installation. Some roofs are ideally suited to solar panels with minimal additional work, while others require structural reinforcement, re-roofing, or alternative mounting approaches. Understanding where your buildings sit on this spectrum is essential before you invest in a solar system, and it directly affects the overall cost of your farm solar installation.

In this guide, we cover every common farm roof type found across the UK, explain the structural and practical considerations for each, and help you understand what assessment process is needed to move forward with confidence. Whether your buildings are brand new or decades old, there is almost always a viable route to generating solar electricity on your farm.

Common Farm Building Roof Types and Their Solar Suitability

UK agricultural buildings feature a wide range of roof constructions. Here is a detailed assessment of each type and what it means for solar panel installation.

Portal Frame Steel Buildings

Excellent for Solar

Portal frame steel buildings are by far the most common modern agricultural building type in the UK, and they are also the best suited for solar panel installations. These structures feature a rigid steel frame with clear spans of 12 to 30 metres or more, clad with profiled metal sheeting on both the roof and walls. The steel frame provides a strong, predictable structural system that can almost always accommodate the additional loading of solar panels without modification.

The roof sheeting on portal frame buildings is typically box profile steel or, on newer structures, standing seam metal cladding. Both of these coverings are ideal for solar mounting systems. The regular, uniform roof surface with long uninterrupted spans provides maximum usable area for panels, and the steel purlins beneath offer reliable fixing points for mounting brackets. Installation on portal frame buildings is straightforward and efficient, keeping labour costs lower than on other building types.

Most portal frame buildings constructed after 1990 have been designed with adequate structural reserve to support solar panels. For older portal frame structures, a brief structural check by a qualified engineer is advisable to confirm the purlin and rafter capacity, but reinforcement is rarely needed. If you have a portal frame building with a sound metal roof, it is almost certainly suitable for solar installation.

Traditional Stone and Brick Barns

Structural Assessment Required

Traditional stone and brick barns are a defining feature of the British farming landscape, particularly in regions such as the Cotswolds, Yorkshire Dales, Peak District, and Welsh borders. These buildings were typically constructed with solid stone or brick walls supporting timber roof trusses, covered with slate, stone tiles, or clay tiles. While they can be used for solar installations, they require careful structural assessment before any work begins.

The primary concern with traditional barns is the structural capacity of the existing timber roof structure. Many of these buildings are over 100 years old, and their roof timbers may have deteriorated due to age, damp, woodworm, or previous modifications. The original design would not have accounted for the additional loading of solar panels. A structural engineer must assess the condition of the rafters, purlins, trusses, and wall plates to determine whether the existing structure can support panels or whether reinforcement is needed.

Where traditional barns are listed buildings or located within conservation areas, there may be additional planning permission requirements for solar panel installations. In some cases, panels may need to be positioned on less visible roof slopes or may require specific heritage-sensitive mounting systems. Despite these considerations, many traditional barns across the UK now successfully host solar panel arrays.

Dutch Barns

Truss Mounting Options Available

Dutch barns are the open-sided, curved-roof structures found on many UK farms, originally designed for hay and straw storage. They consist of a steel or timber frame supporting a curved corrugated roof, with open sides or partial cladding. The open-sided design creates specific challenges for solar installation, but also some unique opportunities.

The curved roof profile of a Dutch barn means that standard flat-mount solar panel systems do not sit flush with the roof surface. Specialist mounting systems that follow the roof curve or tilt panels to an optimal angle can be used, though these add cost and complexity. The open sides of the building increase wind exposure on the underside of the panels, which must be factored into the structural and mounting system design. Wind loading calculations are particularly important for Dutch barn installations.

For Dutch barns with steel trusses in reasonable condition, solar panels can be mounted to the truss structure using bespoke brackets. The truss spacing and strength must be assessed by a structural engineer. In some cases, it is more cost-effective to partially clad the open sides of the barn to reduce wind loading on the panels, which also provides the secondary benefit of better weather protection for stored materials. Dutch barn solar installations require more design work than standard portal frame buildings but can be highly effective when engineered correctly.

Asbestos Cement Roofs

Cannot Mount Directly - Over-Roofing Required

Asbestos cement roofing sheets were widely used on UK farm buildings from the 1950s through to the late 1980s. Any farm building constructed before 1990 with corrugated or profiled cement sheeting should be presumed to contain asbestos until proven otherwise by laboratory testing. It is illegal and extremely dangerous to drill into, cut, or disturb asbestos-containing materials, which means solar panels absolutely cannot be mounted directly onto asbestos cement roofs.

However, having an asbestos roof does not mean solar panels are impossible. The most common and cost-effective solution is over-roofing, where a new metal roof is installed over the top of the existing asbestos sheets without disturbing them. The new roof is supported by additional purlins fixed to the existing structural frame, and solar panels are then mounted to the new metal roof surface. This approach encapsulates the asbestos, provides a brand new weather-tight roof, and creates an ideal surface for solar panel mounting. Over-roofing typically adds £15 to £25 per square metre to the project cost.

The alternative is full asbestos removal and re-roofing, which must be carried out by an HSE-licensed asbestos removal contractor. This is more expensive, typically costing £30 to £50 per square metre for removal plus £20 to £35 per square metre for a new roof covering, but it fully eliminates the asbestos from the building. Many farmers choose to combine asbestos remediation with solar installation as it makes the economics of both projects more attractive when managed together. We cover asbestos management in greater detail below.

Fibre Cement Sheeting

Direct Mounting Possible

Fibre cement sheeting is the modern, asbestos-free replacement for the old asbestos cement sheets that were phased out in the late 1990s. These sheets are made from Portland cement reinforced with synthetic fibres, and they are commonly found on farm buildings constructed or re-roofed from the mid-1990s onwards. Fibre cement sheeting is suitable for direct solar panel mounting with appropriate fixings and load-spreading plates.

When mounting solar panels on fibre cement roofs, it is essential to use the correct fixing system. Panel mounting brackets must be secured through the sheeting into the purlins beneath, with load-spreading washers to prevent localised cracking of the cement sheets. The fixings must also include proper weatherproofing to maintain the roof's water-tightness. While fibre cement is not as strong as metal sheeting, it has adequate load-bearing capacity for solar installations when fixings are correctly positioned at purlin locations. A structural check is recommended for buildings over 20 years old to assess the condition of the sheeting and the underlying structure.

Box Profile Steel Sheets

Ideal for Solar

Box profile steel sheeting, also known as trapezoidal profile cladding, is one of the most common modern roof coverings on agricultural buildings. These sheets feature a repeating pattern of raised trapezoidal ribs that provide structural rigidity and effective water drainage. Box profile steel is an ideal surface for solar panel mounting, with well-established clip-on bracket systems that attach directly to the raised ribs of the sheeting.

The clip-on mounting systems used with box profile steel require no drilling through the roof surface, which preserves the roof's weatherproofing integrity. Brackets clamp onto the standing ribs of the sheeting, and aluminium mounting rails are then attached to support the solar panels. This system is fast to install, cost-effective, and creates a secure, wind-rated mounting that distributes loads evenly across the roof surface. Box profile steel roofs on portal frame buildings represent the easiest and most economical combination for farm solar installations, which is why the majority of the agricultural solar systems we install are on this type of building.

Standing Seam Metal Roofs

Best for Solar

Standing seam metal roofs are widely regarded as the single best roof type for solar panel installations. These roofs feature long, continuous metal sheets joined by raised vertical seams that run from ridge to eaves. The raised seams provide a natural and exceptionally strong attachment point for solar panel clamp systems, requiring absolutely no penetrations through the roof surface.

Standing seam clamp systems use specially designed metal clamps that grip onto the raised seams and lock in place without any drilling, screwing, or adhesive. This preserves the full weather integrity of the roof and makes installation remarkably quick and clean. The clamps can be adjusted along the length of the seam to achieve optimal panel spacing, and they are engineered to withstand significant wind uplift loads. Standing seam roofs are increasingly specified on new agricultural buildings in part because of their superior compatibility with solar panel systems. If your farm building has a standing seam metal roof, you have the ideal foundation for a high-performing, long-lasting solar installation.

Structural Loading Considerations

Understanding the structural loads that solar panels impose on your farm building is critical to a safe and successful installation.

Dead Load: Panel Weight

Solar panels and their mounting systems add a dead load of approximately 12 to 15 kg per square metre to the roof structure. This includes the weight of the panels themselves (typically 20 to 25 kg each, spread over approximately 2 square metres), the aluminium mounting rails, brackets, and fixings. For a 100kW system covering roughly 500 square metres, this equates to a total additional weight of around 6,000 to 7,500 kg distributed across the roof. While this sounds significant, it is relatively modest compared to the design loads that most agricultural buildings are engineered to withstand.

Wind Loading

Wind loading is often more critical than the static weight of the panels, particularly on exposed agricultural sites. Solar panels create both downward pressure and uplift forces depending on wind direction, with the most significant forces occurring at roof edges and corners. The mounting system must be designed to resist wind uplift forces, which on an exposed farm site can exceed 1.5 kN per square metre. Wind loading calculations must comply with BS EN 1991-1-4 and take account of the specific site topography, building height, roof pitch, and panel position. Buildings in open, flat terrain such as fenland farms or coastal locations experience higher wind loads than sheltered inland sites.

Snow Loading

Snow loading must be considered in the structural assessment, particularly for farms in northern England, Scotland, and upland areas where significant snowfall occurs. The UK snow load map divides the country into zones with ground snow loads ranging from 0.3 kN per square metre in the south-west to over 1.0 kN per square metre in the Scottish Highlands. Solar panels can cause snow to accumulate differently on the roof compared to an uncovered surface, and this must be factored into the loading calculations. In most cases, the combined dead load of panels plus the design snow load remains within the structural capacity of the building, but this must be verified by calculation rather than assumption.

When Is Structural Reinforcement Needed?

Structural reinforcement is typically required in the following situations:

Older buildings designed before modern loading standards were adopted, particularly those built before the 1980s with lightweight steel or timber frames
Buildings with visible signs of structural distress such as sagging purlins, deflected rafters, cracked welds, or corroded steelwork
Traditional timber-framed barns where the roof structure has deteriorated due to age, moisture ingress, or insect damage
Buildings in high wind exposure zones where the additional uplift forces from panels exceed the existing structural capacity
Dutch barns and open-sided structures where wind can access the underside of panels, significantly increasing uplift forces

Structural Assessment Process

A professional structural assessment typically involves a site visit by a chartered structural engineer who will inspect the building frame, measure key structural members, assess condition, and carry out loading calculations. The engineer will produce a written report confirming whether the building can support solar panels as-is, or specifying what reinforcement is needed. Common reinforcement measures include adding extra purlins, strengthening existing purlins with steel plates, adding bracing to portal frames, or replacing damaged structural members. The cost of structural reinforcement varies widely, from as little as £2,000 for minor purlin strengthening to £15,000 or more for significant frame modifications. Your solar installation provider should arrange the structural assessment as part of the project planning process.

Roof Orientation and Pitch

The orientation and angle of your farm building roof directly affect how much electricity your solar panels will generate throughout the year.

South-Facing

100%

Maximum output

South-facing roofs receive the most direct sunlight across the year and are the ideal orientation for solar panels in the UK. A south-facing roof at a pitch of 30 to 35 degrees delivers the theoretical maximum annual electricity generation.

South-East / South-West

95%

Near-optimal output

Roofs facing south-east or south-west achieve approximately 95 percent of the output of a due-south system. The slight loss is negligible in practical terms, and these orientations are considered excellent for solar installations.

East or West

85-90%

Viable and often advantageous

East and west facing roofs produce 85 to 90 percent of the output of a south-facing system. On dual-pitch farm buildings, installing panels on both east and west slopes maximises total generation and spreads output across the day.

North-Facing

50-65%

Generally not recommended

North-facing roofs receive significantly less direct sunlight and are generally not recommended for solar panel installations in the UK. The reduced output rarely justifies the installation cost, although at very low pitches the reduction is smaller.

Understanding Roof Pitch for Solar Panels

The pitch or angle of your farm building roof affects solar output as well as the mounting approach. The optimal pitch for solar panels in the UK is between 30 and 35 degrees from horizontal, which maximises the annual solar energy captured. However, most farm buildings have roof pitches between 10 and 22 degrees, which is lower than the ideal but still very effective.

A minimum pitch of approximately 10 degrees is generally recommended for solar panels to ensure that rainwater runs off the panel surface, keeping them naturally clean. Flat or very low-pitched roofs below 10 degrees can still be used, but tilt-mounted frames may be specified to raise the panels to a more productive angle and ensure self-cleaning. Tilt frames add cost and complexity, and the spacing between rows to avoid self-shading reduces the total number of panels that can fit on the available roof area.

Steeper pitches above 35 degrees are less common on farm buildings but are found on some older barns and converted agricultural structures. At steeper angles, summer generation decreases slightly while winter generation improves, resulting in a more consistent output across the seasons. Panels on steep roofs also shed snow more effectively, which is beneficial for farms in upland areas.

Shading Assessment

Shading is one of the most significant factors affecting solar panel performance, and even small areas of shadow can disproportionately reduce the output of an entire panel string. A thorough shading assessment is an essential part of any farm building solar survey.

Trees and Hedgerows

Mature trees near farm buildings are the most common source of shading problems. Deciduous trees cause shading primarily in summer when they are in full leaf, which unfortunately coincides with the peak solar generation period. Evergreen trees and tall hedgerows can cause shading year-round. When assessing tree shading, it is important to consider the sun's path throughout the year, as shadows are longer and cast further in winter when the sun is lower in the sky. Trees to the south, south-east, and south-west of the building are the most problematic. In some cases, selective tree management or pruning can resolve shading issues, but this should always be assessed with regard to tree preservation orders and ecological considerations.

Adjacent Buildings and Silos

On farmsteads with multiple buildings, adjacent structures can cast shadows onto the roof being considered for solar panels. Grain silos, feed towers, taller barn buildings, farmhouses, and even telegraph poles can all cause localised shading. The impact depends on the height and proximity of the obstruction, the orientation of the roof, and the time of year. Modern system design software uses 3D modelling and sun path analysis to precisely map shadow patterns across the roof surface throughout the year, allowing panels to be positioned in the areas with least shading impact. In some cases, power optimisers or microinverters can be used to mitigate the effect of partial shading on system output.

Chimneys, Vents, and Roof Obstructions

Chimneys, ventilation turrets, roof lights, and other protrusions on the building itself can cause localised shading on nearby panels. While these obstructions are relatively small, their proximity to the panels means they can cast sharp shadows during parts of the day. The panel layout should be designed to maintain adequate clearance from all roof obstructions, and power optimisers can be fitted to panels in partially shaded positions to minimise the impact on overall system output. Ridge vents and ventilation outlets on livestock buildings need particular attention, as they are often positioned along the full length of the roof ridge.

How We Assess Shading

Our site survey process includes a comprehensive shading analysis using specialist sun path instruments and 3D modelling software. We measure the horizon profile from the roof surface to identify all sources of shading throughout the year, and produce a detailed shading report that shows the expected impact on annual energy generation. This allows us to design the optimal panel layout for your specific building and ensure the predicted generation figures in your quotation are accurate and achievable. If significant shading is identified, we will advise on the best mitigation strategies, whether that is adjusting the panel layout, using optimised electronics, or considering an alternative building on your farm. Contact us to arrange a site survey.

Roof Age and Condition Assessment

The age and current condition of your farm building roof are crucial factors in determining solar suitability. Solar panels are designed to last 25 to 30 years, so it makes sense to ensure your roof will remain in good condition for at least that long. Installing panels on a roof that will need replacing in five years is a costly mistake that can be avoided with proper assessment.

Metal Roof Coverings

Modern metal roof sheeting such as box profile steel or standing seam panels has a typical lifespan of 30 to 40 years when properly maintained, with premium coatings lasting even longer. Assess the condition of the paint or coating finish, check for signs of corrosion, particularly at cut edges and fixings, and look for areas of denting or damage. Minor surface corrosion can be treated and is not usually a barrier to solar installation. However, if the sheeting is severely corroded, perforated, or approaching the end of its service life, it is more cost-effective to re-roof before installing solar panels. On older metal roofs, check that the fixings are still tight and the weather seals are intact.

Fibre Cement and Slate Roofs

Fibre cement sheets have a typical lifespan of 25 to 35 years. Look for cracking, delamination, moss or algae growth, and whether fixings are still secure. Cracked sheets should be replaced before solar panels are installed. Natural slate roofs on traditional barns can last well over 100 years if the underlying timber structure remains sound, but individual slipped or broken slates should be repaired. The condition of flashings, ridge tiles, and valleys should also be checked, as these are common points of failure on older roofs.

The 10-Year Rule

As a general guideline, if your roof covering has less than 10 years of remaining service life, it is worth considering re-roofing before or as part of the solar installation project. Removing panels to replace the roof mid-way through their life is expensive and disruptive, typically costing £3,000 to £8,000 for removal and reinstallation depending on system size. Planning for a new roof and solar panels together allows the costs to be optimised and may qualify for combined financing. Our surveyors assess roof condition as a standard part of every site visit and will advise honestly if re-roofing should be considered before solar installation proceeds.

Asbestos Management for Farm Solar Projects

Asbestos cement roofing is extremely common on UK farm buildings built before 1990. Managing asbestos correctly is a legal requirement and a critical step in many farm solar projects.

Identifying Asbestos on Farm Buildings

Asbestos cement was widely used for farm roofing and cladding from the 1950s through to the late 1980s. It was typically supplied as corrugated or profiled grey sheets that look similar to modern fibre cement products. Visual identification alone is not reliable, as asbestos cement and modern fibre cement sheeting are very similar in appearance. Any building constructed before 1990 with cement-based roofing should be tested by an accredited laboratory to confirm whether asbestos is present. A Refurbishment and Demolition (R&D) survey, carried out by a UKAS-accredited surveyor, is the appropriate survey type for farm buildings where work is planned that may disturb the roof material.

HSE Regulations and Legal Requirements

Under the Control of Asbestos Regulations 2012, the duty holder for a farm building with asbestos-containing materials must manage those materials to prevent fibre release. Drilling, cutting, or mechanically fixing through asbestos cement sheets is classified as licensable work and can only be carried out by an HSE-licensed asbestos removal contractor. This is why solar panels cannot be mounted directly to asbestos roofs using conventional fixings. Non-licensed work, such as minor repairs or encapsulation, must still follow HSE guidance and be carried out by trained operatives. Failure to comply with asbestos regulations carries severe penalties including unlimited fines and criminal prosecution.

R&D Survey Process

A Refurbishment and Demolition survey involves a UKAS-accredited surveyor visiting the site, taking representative samples of the roofing material, and sending them for laboratory analysis. The survey report will confirm whether asbestos is present, identify the type of asbestos (typically chrysotile in cement sheets), assess the condition of the material, and recommend appropriate management actions. The survey typically costs £300 to £600 for a single farm building and takes around one to two weeks to complete including laboratory analysis. We arrange R&D surveys for our customers as part of the project planning process when asbestos is suspected.

Over-Roofing vs Full Removal: Cost Comparison

When asbestos is confirmed, there are two main approaches to enable solar panel installation:

Over-Roofing (Encapsulation)

New metal sheeting is installed over the existing asbestos sheets using a spacer and purlin system that avoids disturbing the asbestos below.

Cost: £15 - £25 per m2

- Lower cost than full removal
- Faster installation with less disruption
- Asbestos encapsulated and managed in situ
- New roof surface ideal for solar mounting
- Building can remain in use during works

Full Asbestos Removal and Re-Roofing

All asbestos sheets are removed by a licensed contractor, disposed of at a licensed facility, and a new roof covering installed.

Cost: £50 - £85 per m2 (removal + new roof)

- Complete elimination of asbestos from building
- Opportunity to upgrade insulation and structure
- May be required if asbestos is in poor condition
- Higher cost but longer-term solution
- Building must be vacated during removal works

For a typical 600m2 farm building roof, over-roofing costs approximately £9,000 to £15,000, while full removal and re-roofing costs approximately £30,000 to £51,000. Many farmers choose over-roofing as the more cost-effective route, combining the new roof cost with their solar investment to improve the overall project economics.

Combining Asbestos Work with Solar Installation

One of the major advantages of combining asbestos management with a solar installation project is the opportunity to achieve two important improvements to your farm building in a single, coordinated project. The new roof provides a 30 to 40 year weather-tight covering, the asbestos risk is managed or eliminated, and the solar panels generate significant ongoing financial returns that help offset the combined project cost. We have extensive experience managing combined asbestos and solar projects and work with trusted, HSE-licensed asbestos contractors to deliver seamless, fully compliant projects from initial survey through to solar commissioning.

Ground-Mounted Solar: When Your Roof Is Not Suitable

In some cases, a farm building roof may simply not be suitable for solar panels due to structural limitations, excessive shading, poor orientation, or an uneconomic asbestos situation. When this is the case, ground-mounted solar arrays offer an excellent alternative that can often deliver even better performance than roof-mounted systems.

Advantages of Ground-Mounted Systems on Farms

Optimal orientation and tilt: Ground-mounted frames can be positioned at the ideal south-facing orientation and 30 to 35 degree tilt angle, regardless of building orientation, maximising energy generation.
No structural limitations: Ground-mounted systems do not impose any loading on existing buildings, eliminating the need for structural assessment or reinforcement.
Easier maintenance: Panels at ground level are much easier to clean, inspect, and maintain than roof-mounted systems, reducing long-term operating costs.
Scalable: Ground-mounted arrays can be sized to match your energy requirements without being limited by available roof area.

Planning Considerations for Ground-Mounted Systems

Ground-mounted solar arrays on farmland generally require planning permission, unlike many roof-mounted installations that fall under agricultural permitted development rights. The planning process considers visual impact, use of agricultural land, ecology, flood risk, and impact on the landscape. Systems under 50kW on farmsteads may qualify for simplified planning routes in some local authority areas. Larger systems will need a full planning application with supporting documents.

Ground-mounted systems also require a suitable area of land that is relatively flat, well-drained, not prone to flooding, and located reasonably close to the farm's electrical connection point. The cost of cabling from a distant array back to the farm buildings and the grid connection must be factored into the project economics. Despite these additional considerations, ground-mounted solar is an increasingly popular choice for farms where roof installation is not practical.

Roof Suitability at a Glance

Use this summary table to quickly assess the solar suitability of your farm building roof type. For a definitive assessment, book a free site survey with our agricultural solar specialists.

Roof Type	Solar Suitability	Mounting Method	Additional Works
Standing Seam Metal	Best	Seam clamp system, zero penetrations	None typically required
Box Profile Steel	Excellent	Clip-on rib brackets	None typically required
Portal Frame (metal clad)	Excellent	As per roof covering type	Structural check on older buildings
Fibre Cement Sheeting	Good	Through-fix with load spreaders	Condition check, possible sheet replacement
Traditional Stone/Brick Barn	Assessment Needed	Roof-specific fixings	Structural survey, possible reinforcement
Dutch Barn	Assessment Needed	Truss-mounted brackets	Structural survey, wind loading design
Asbestos Cement	Over-Roofing Required	Mount to new over-roof	R&D survey, over-roof or removal

Frequently Asked Questions About Farm Roof Suitability

Find answers to the most common questions about assessing farm building roofs for solar panel installations.

Can you put solar panels on an asbestos farm roof?

What is the best farm roof type for solar panels?

How much weight do solar panels add to a farm roof?

Do solar panels work on east or west facing farm roofs?

How do I know if my farm building roof is strong enough for solar panels?

Get Expert Advice on Your Farm Roof

Not sure whether your farm building roof is suitable for solar panels? Our team has assessed hundreds of agricultural buildings across the UK, from modern portal frame steel structures to century-old stone barns. We can quickly evaluate your building and recommend the best path forward.

Your Free Roof Assessment Includes:

Visual roof condition inspection and covering identification
Preliminary structural capacity assessment
Asbestos identification and management advice
Orientation and shading analysis
Recommended system size and estimated generation
Detailed quotation with transparent cost breakdown

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