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OPINION
27 October 2026 · By Geoff Wilkinson
Architects are specifying solar systems on roofs without considering the fire risk implications, warns Geoff Wilkinson 
Within the next two to three years, most architects will find themselves specifying solar photovoltaic systems as a matter of course. Net-zero carbon ambitions, Building Regulations Part L requirements and client expectations have shifted the conversation from ‘should we have solar?’ to ‘where and how many panels?’ In most cases, the answer is on the roof. This means that architects need to start considering the fire risk. As principal designer, the responsibility lies with them, not the PV installer.
Across the UK, nearly 172,000 solar installations have been fitted since the start of 2026, with increases everywhere over the past 12 months. More than 19,800 rooftop solar panels were installed in July alone – equivalent to an installation every two minutes. At the same time, solar panel roof fires in the UK have risen 133 per cent, from 91 incidents in 2022 to 212 in 2025, according to a report by insurers QBE European Operations. QBE’s data shows most incidents involving a solar panel took place in residential buildings, with 102 fires in 2025. However, commercial and industrial property fires involving solar panels also rose from 2024 to 2025.
PV panels are electrical components, so the risk of fire can never be truly eradicated
A lot of the focus to date has been on the panels themselves, inverters, battery storage banks and damaged or faulty wiring. These are the causes of fires. However, architects need to consider not only that the products being tested are suitable but, as principal designer, also how a known fire risk can be controlled or mitigated so it does not spread disproportionately.
Here, considerations such as hidden voids beneath arrays, long cable runs and risk of animal damage are important risks to design out. Furthermore, evidence is emerging that panels placed too close to the roof surface can accelerate flame spread during a structural fire. Historically, roofs were primarily considered not to need fire resistance, unlike structural elements such as floors or walls. The focus was therefore on preventing burning material from an adjacent building fire landing on the roof and spreading the fire from one building to another. Architects will be familiar with this and the need for space separation between buildings – and for roof surfaces to have a BROOF (t4) fire performance classification.
The standards that apply are:
Key design considerations for architects are:
Many architects do not think about these issues during design. They specify solar PV, hand the detail to the electrical engineer and assume building control will check it. The result: installations go ahead with suboptimal fire stopping, inadequate cavity closures, or roof membrane penetrations that are not properly sealed.
PV panels are electrical components, so the risk of fire can never be truly eradicated. But the damage done if a fire occurs can be reduced by increasing the fire resistance of the assembly. A simple way is to use non-combustible materials wherever possible and install fire-rated cover boards between the waterproofing and insulation layer.
On your roof plans and sections, clearly indicate that any penetrations through fire-rated elements (ceiling, roof, party walls) will be sealed in accordance with BS 9414. Specify that penetrations in cavities will be backed by cavity barriers. If ventilation cavities continue beyond the panel area, specify how they are closed or fire-stopped.
Ensure that the design details presented to building control and the contractor are sufficiently detailed: sketch how the panels will be mounted, where penetrations will be and what fire stopping solution you propose. If building control raises a concern, address it in the specification stage, not during construction. If the building has complex roof systems – HVAC plant, cable trays, and so on – involve the M&E team early. Confirm that the solar mounting system does not interfere with ventilation, does not route cables next to high-temperature plant and does not create new fire paths between systems.
Geoff Wilkinson is managing director of Wilkinson Construction Consultants
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Tagsfire safety roofing solar panels The regs
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