Is Your Roof Suitable for Commercial Solar?
The key things that decide whether your commercial roof can take solar panels: roof type, condition, structure, orientation, shading and access, plus what to do if it can’t.
Quick checklist
Key takeaways
- Most modern commercial roofs, including profiled steel and flat membrane roofs, can take solar.
- The roof should have enough life left to outlast the panels, ideally 20 years or more.
- A structural assessment confirms the building can carry the extra load.
- East–west layouts work well for businesses, spreading generation across the day.
- If the roof isn’t suitable, ground-mounted solar or a solar car park may be an option.
Common Commercial Roof Types
Profiled steel
The most common industrial roof (ridged metal sheets). Panels sit on rails clamped to the ridges, usually without drilling through the roof.
Standing seam
Excellent for solar. Clamps fix straight onto the raised seams, with no holes in the roof.
Flat membrane
Panels sit on angled frames, either held down by weights (ballasted) or fixed to the roof, often in an east–west layout.
Fibre cement
Common on older buildings and farms. It needs careful assessment, as some older sheets can contain asbestos and may be fragile.
Fragile roof sheets and rooflights are a serious fall risk. Any survey or installation must be planned with proper access and edge protection.
Roof Condition and Age
Solar panels last 25 years or more, so your roof should too. If it will need replacing in the next few years, it’s usually better to do that first. Removing and refitting panels later adds cost and downtime.
- Check for corrosion, leaks, damaged sheets or failing fixings.
- Look at any warranties on the existing roof covering.
- Check whether repairs or over-cladding (a new metal skin fitted over the old roof) are needed before installation.
If your roof needs replacing anyway, combining it with solar can be cost-effective, because you share the access and scaffolding costs.
Structural Loading
A solar system adds weight to your roof. Rail-mounted systems on pitched roofs are relatively light, while ballasted systems on flat roofs are heavier. Wind and snow loads also need to be considered.
A structural assessment checks that the roof frame, such as the purlins (beams that hold up the roof sheets), rafters and trusses, can safely carry the extra load. If it can’t take much more weight, lighter fixings or strengthening may be options.
Orientation and Pitch
South-facing roofs give the highest total generation, but they’re not the only option. For businesses, east–west layouts often work just as well, because they spread generation across the morning and afternoon, closer to how most sites use power.
- South-facing: the highest overall output.
- East–west: more even output through the day and more panels per roof.
- North-facing: usually less suitable, unless the roof is nearly flat.
Shading
Shade from taller buildings, trees, chimneys, plant rooms or parapets (low walls round the roof edge) can reduce output. A good design maps shading across the year and positions panels to avoid it. Optimisers (devices fitted to each panel) or the right inverter setup can reduce the effect of shade you can’t avoid.
Access, Safety and Fire
- Access: safe routes for installation and future maintenance, including edge protection.
- Fire safety: layout, cable routes and isolation (ways to switch it off safely) designed in line with RC62 fire safety guidance.
- Insurance: speak to your insurer early, as many have specific requirements.
- Leases: if you rent, you’ll usually need landlord consent.
If Your Roof Isn’t Suitable
Not every roof is right for solar, but that doesn’t mean solar isn’t right for you. Alternatives include:
- Ground-mounted solar on unused land.
- Solar car park canopies.
- Combining roof replacement with a new solar installation.
- Using a different building on the same site.
Frequently Asked Questions
Can solar go on an asbestos roof?
Sometimes, but it needs careful assessment and specialist handling. Options include specialist fixings, over-cladding or replacing the roof first. Never drill or walk on a suspected asbestos roof without proper controls.
Will solar panels damage my roof?
Not when they’re designed and installed properly. Most systems on steel and standing seam roofs use clamps, so there’s no need to drill through the roof covering.
Do flat roofs work for solar?
Yes. Panels are mounted on angled frames, often in an east–west arrangement to fit more panels and reduce wind loading.
How do I know if my roof is strong enough?
A structural assessment will confirm it. We include roof and structural checks as part of our survey and design process.
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