Solar Panels and Fire Spread Over Pitched Roofs: What Recent Government Research Means for Building Owners

Over the last ten years we have seen the number of solar photovoltaic (PV) panels on roofs grow significantly across our home region of Chester, the North West and North Wales. Domestic housing, care homes, schools, commercial premises and mixed-use buildings are increasingly adopting rooftop solar as part of decarbonisation and cost-reduction strategies. For many building owners and managers, installing solar panels makes complete commercial sense. However, like any other electrical system, solar panels also pose a fire hazard. According to insurer QBE, fires involving solar panels saw a 60% increase in the past two years and UK fire services tackle a solar panel fire every two days. You may have even noticed some of the high profile PV fires last year, such as the Bristol's St Michael's Hospital below.

Understanding how a solar panel fire would impact your building and what mitigations must be in place is therefore important. A recent experimental study published by the Building Safety Regulator and the Health and Safety Executive examined fire spread over pitched roofs fitted with solar panels. While the research is technical in nature, the findings are relevant to anyone responsible for the safety of a building with rooftop PV. You can read the full report here.

Why This Research Matters

Historically, external fire spread across roofs has been assessed using standard roof classifications. However, solar panels introduce additional materials, voids and fixing systems above the roof surface. This research set out to understand how those additions can affect fire development and flame spread. The tests focused on pitched residential roof constructions fitted with different types of PV panels and mounting arrangements, observing how fire behaved once it reached roof level.

What the study found

The research showed that solar panels can change how fire spreads across a pitched roof, and that not all systems behave in the same way. Key observations included:

Panel construction matters
Plastic-backed PV panels were shown to support more sustained flame spread up the array. In contrast, glass-backed panels generally limited fire spread, with flames remaining closer to the point of ignition.

Roof performance alone is not the full picture
Even where the underlying roof covering achieved a recognised fire performance classification, the addition of PV panels altered the fire behaviour. In some tests, flames spread beneath the panels and re-emerged above the roofline.

Heat can become trapped beneath arrays
The space between the roof covering and the solar panels allowed heat to build up, increasing thermal exposure to roof materials compared with a roof without PV.

It is important to note that this research represents early experimental data and forms part of a wider programme of research. However, the direction of travel is clear: from a fire safety and compliance perspective, PV systems are no longer seen as neutral additions.

What This Means for You

This research reinforces several important points:

Solar panels should be considered within fire risk assessments
Where a building has rooftop PV, those panels form part of the external fire spread risk. They should be considered when assessing roof construction, boundary distances, proximity to neighbouring buildings and potential fire spread routes.

Specification and installation are critical
The fire performance of a PV installation is influenced by panel type, backing materials, mounting systems and how the array interacts with the roof covering beneath. Competent design and accredited installation are essential, particularly on residential buildings or premises with sleeping risk.

Existing buildings may need review
Where solar panels have been added since the last fire risk assessment, this may represent a material change. In some cases, a review of the building’s fire risk assessment is appropriate to ensure the risks introduced by the installation have been properly considered.

Fire service access and response should not be overlooked
PV systems can affect firefighting tactics, particularly roof access and electrical isolation. These practical considerations should be reflected in emergency planning and building information, especially for larger or more complex sites.

Looking Ahead

This research will inform future guidance and regulatory expectations. While it does not mean that solar panels are unsafe, it does underline that they are a fire safety consideration that must be addressed properly rather than assumed to be benign. As buildings evolve, fire risk assessments must evolve with them.

How Fletcher Risk Can Help

At Fletcher Risk, we assess buildings as they are actually used, not as they were originally designed. Where solar panels are present, we consider how they interact with the roof, the wider site and neighbouring properties, and we provide clear, proportionate advice aligned with current evidence and emerging guidance. If your building in Chester, the North West or North Wales has rooftop solar, or you are planning an installation, we would be happy to advise on whether your fire risk assessment needs review and what practical steps may be appropriate.

Please contact us today to discuss your building and arrange a fire risk assessment.

Disclaimer
This article is intended to provide general information on recent fire safety research relating to solar photovoltaic panels. It does not constitute legal, design or installation advice. Fire safety requirements vary depending on building type, construction and use, and guidance continues to evolve. Building owners and Responsible Persons should seek competent professional advice specific to their premises.

© Fletcher Risk Team - 30 January 2026