Farm Building Roof Assessment for Solar
Free farm building roof assessment for solar panels. We survey roof type, structural capacity, orientation, and asbestos risk. Expert agricultural building analysis.
Every farm building is different. Before designing a solar system, we conduct a thorough roof assessment covering material identification, structural capacity, orientation analysis, and condition evaluation. This guide explains what we look for and why it matters.
2-3 Hours
Survey Time
5 Days
Report Delivery
Free
Cost
What Our Farm Roof Assessment Covers
A comprehensive agricultural building survey examines four critical areas to determine solar feasibility, optimal system size, and expected financial returns.
Farm Roof Types and Solar Compatibility
The roof material is the single most important factor in determining installation method, timeline, and cost. Here is how each common agricultural roof type works with solar.
Structural Load Calculations
The structural assessment ensures your building safely supports solar panels through their entire 25+ year lifespan under all weather conditions.
Farm Roof Assessment FAQs
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Related Guides
Highlights
- Panel Dead Load
- 12-15 kg/m²
- Weight of panels, mounting rails, and fixings. This permanent load must be within the roof structure design capacity.
- Wind Uplift
- Varies by location
- Panels increase wind uplift forces on the roof. Fixing calculations account for the specific wind zone and building height.
- Snow Loading
- 0.3-0.7 kN/m²
- UK snow load zones affect the combined dead plus imposed load calculations. Highland areas require additional structural margin.
- Purlin Spacing
- Typically 1.2-1.8m
- Mounting rails span between purlins. Standard spacing of 1.2-1.8m is ideal. Wider spacing may need intermediate support rails.
- Column Loading
- Cumulative check
- Total additional roof load transfers through columns to foundations. Portal frame buildings generally have adequate reserves.
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Roof Structure Types Found on UK Farm Buildings
UK farm buildings span over 100 years of construction methods, each with different implications for solar installation. Understanding the roof type is the first step in any farm solar assessment — it determines the mounting system, structural requirements, and in some cases whether installation is feasible at all without remediation.
| Roof Type | Era | Solar Suitability | Key Considerations |
|---|---|---|---|
| Steel portal frame + profile steel sheets | 1980s-present | Excellent | Standard agricultural solar profile; no asbestos risk |
| Steel portal frame + profiled fibre cement (non-AC) | 1970s-present | Good | Check condition; non-asbestos fibre cement is fine |
| Asbestos Cement (AC) corrugated sheets | 1950s-1990s | Variable — see below | Survey required; may need over-clad or cap sheet |
| Traditional timber truss + Welsh slate | Pre-1950s | Moderate | Structural survey essential; load capacity may be limited |
| Timber frame + clay/concrete interlocking tiles | Pre-1970s | Moderate | Standard residential-style mounting if roof is sound |
| Concrete portal frame + profiled concrete sheets | 1960s-1980s | Good | Fixings may need specialist drilling; durable when sound |
| Cold-store / insulated panel construction | 1980s-present | Good | Fixings into structural rail; lighter panels preferred |
Asbestos Cement Roofs: The Common Issue on UK Farms
Asbestos Cement (AC) corrugated roofing sheets were the standard agricultural roofing material from the 1950s through the late 1980s. A significant proportion of UK farm buildings still have AC roofs — typically dark grey corrugated sheets that have often become fragile, cracked or discoloured with age. Solar installation on AC roofs requires careful management.
The Health and Safety Executive (HSE) classifies AC roofing sheets as a non-licensed asbestos product. This means they can be worked on (including solar panel installation) by trained contractors without a HSE removal licence, provided a risk assessment and method statement are in place and the sheets are not friable (crumbling). Installation by walking on the roof is prohibited; all work must be done from purpose-built working platforms over the roof.
For AC roofs in fair to good condition (no significant cracking, spalling or delamination), solar panels can be installed on an over-cladding framework that avoids direct contact with the AC sheets. The panels effectively sit on a rail system attached to the purlins through the AC sheets — specialist fixings penetrate the sheets but do not damage the asbestos matrix if correctly installed. This approach, known as non-intrusive AC fixing, is widely used on UK farm buildings.
Roof Load Capacity: What Solar Weighs
Commercial solar panels weigh approximately 20-22 kg each. A standard 400W panel measures 2.0m x 1.0m and weighs 21kg — approximately 10.5 kg/m² for the panel itself. Adding mounting rails, fixings and ballast blocks (on flat roofs), the total added load is typically 15-25 kg/m² for a pitched roof system and 20-35 kg/m² for a flat-roof ballasted system.
Most post-1970 steel portal frame agricultural buildings are designed to BS 5502 (Agricultural Buildings Code), which specifies minimum superimposed load capacity of 0.3-0.6 kN/m² depending on building function. A 100kW solar installation on a 1,000m² roof adds approximately 0.15-0.25 kN/m² of distributed load — within the structural reserve of most modern agricultural buildings. However, snow loading is additive: in areas of moderate snow loading (most of England and Wales), the combined snow plus solar load should be checked by a structural engineer for buildings over 15 years old.
Orientation and Shading Assessment
Farm buildings vary enormously in roof orientation — from single-span mono-pitch buildings facing due south (ideal) to multi-span sawtooth roofs alternating south-east and south-west facets, to east-west oriented portal frame buildings that offer equal east and west roof halves. The orientation assessment determines generation yield.
| Orientation | Azimuth | Yield vs True South | Notes |
|---|---|---|---|
| True South | 180° | 100% (baseline) | Ideal; maximum annual generation |
| South-East | 135° | 95-97% | Slightly less total but better morning profile |
| South-West | 225° | 95-97% | Better afternoon profile; suits some load patterns |
| East | 90° | 75-80% | Viable; two arrays can be installed on E+W |
| West | 270° | 75-80% | Viable; good for afternoon-heavy loads |
| North | 0° | 50-60% | Poor; only viable if no south-facing roof available |
For east-west oriented farm buildings (common for large grain stores and machine stores aligned with field access), an east-west split installation — equal area facing east and west at 10° tilt — typically generates 85-90% of an equivalent south-facing yield, while using the full roof area and significantly reducing wind loading compared to south-facing high-tilt panels.
Do I need a structural engineer report before installing farm solar?
For most steel portal frame buildings constructed after 1970 with roofs in good condition, a structural survey is not a legal requirement — the installer's own structural assessment and manufacturer load calculations are sufficient. However, a structural engineer report is recommended for: buildings over 30 years old, concrete frame buildings, timber-framed roofs, buildings that have been modified or extended, and any building where the roof condition is uncertain. Our survey team flags any structural concerns during the free site assessment and recommends specialist surveys where needed.
Can solar be installed on a barn with a curved or round roof?
Curved or round roofs (Crendon buildings, Dutch barns with rounded profiles) present challenges for standard flat-mounting systems. Specialist flexible mounting solutions are available that follow a gentle roof curve, but very tight curves (radius below 10m) are typically not suitable for rigid crystalline panels. In these cases, a ground-mounted system adjacent to the building is often more cost-effective than a complex roof mounting solution.
Book a Free Farm Roof Solar Assessment
MCS-certified installation. Free site survey. AIA tax relief and Class R PD guidance included.
Get a Free SurveyOur farm roof solar assessment process is designed to be comprehensive and farm-friendly. We visit at a time convenient to the farm calendar, complete a full structural and planning assessment, and provide a written report confirming suitability, recommended system size and financial model — all at no cost and with no obligation to proceed with installation. Contact us to arrange your farm's free solar roof assessment.
Book your free farm roof solar assessment today. Our agricultural solar specialists visit at a time to suit your farm calendar, complete the full structural and planning check, and provide a written report with no obligation to proceed.
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MCS-certified installation. Free site survey. AIA tax advice included.
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