Solar panels can sometimes be installed on an older commercial roof, but age alone does not answer the question. Roof condition, remaining life, structure, covering, warranty, access and hazardous materials must be understood before committing to an array.
Why remaining roof life matters
Commercial solar equipment may remain in service for decades. If the roof needs replacement part-way through, panels and electrical equipment may need to be removed, stored and reinstalled. Where substantial roof work is likely soon, coordinating reroofing with solar may produce a better long-term result.
What should a roof assessment cover?
- roof covering and fixings;
- leaks, corrosion or deterioration;
- remaining service life;
- structural capacity and deflection;
- wind and snow loading;
- rooflights, drainage and maintenance routes;
- existing warranties; and
- safe access and fragile-roof risks.
Will solar invalidate the roof warranty?
It depends on the warranty and mounting method. The building owner should consult the roof-system manufacturer, warranty provider, insurer and relevant advisers. Responsibilities for penetrations, inspections and remedial work should be documented.
What about asbestos-containing materials?
Older commercial and agricultural buildings may contain asbestos. It cannot be identified reliably from a photograph alone. The dutyholder must manage asbestos risk and appropriate survey information may be required before intrusive work.
Solar installers should not disturb suspected materials without the correct assessment, method, competence and controls. Roof replacement or specialist work may be necessary.
Can structural strengthening be required?
Yes. Panel and mounting loads, wind effects and the existing structure must be considered. Visual roof condition does not prove structural capacity.
Which mounting method is best?
There is no universal method. The solution depends on roof type, profile, structure, weather exposure, drainage and warranty requirements. A mounting design should be project-specific.
Questions for building owners
- When was the roof installed?
- Is there a current condition report?
- Who holds the warranty?
- Are asbestos records available?
- Are repairs or redevelopment planned?
- How will the roof be accessed after installation?
