With the UK experiencing increasingly extreme and unpredictable weather, NFRC’s Gary Walpole explains why climate resilience can no longer be overlooked when designing, installing or refurbishing roofs.
Five years ago, NFRC’s Future (P)roof research warned that the UK’s roofs would need to cope with hotter summers, heavier rainfall and weather extremes their designers had never planned for. In 2026, those predictions have truly come to pass.
The research, which the NFRC Charitable Trust commissioned the University of Southampton to conduct, went beyond reducing carbon emissions to consider the role of the roof space in adapting the built environment to emerging challenges including warmer temperatures, more frequent and intense heatwaves, extreme rainfall and other changing climatic conditions.
By August this year, parts of the UK had endured their fifth heatwave of the year. Temperatures of 35°C or above were recorded in May, June and July for the first time on record. Researchers from Imperial College London, the Met Office and the London School of Hygiene & Tropical Medicine estimate that more than 2,700 people died from heat-related causes during the May and June heatwaves alone, with climate change responsible for around 42% of those deaths. July was the driest in 190 years, and three-quarters of England fell into drought.
Yet heat and drought are only half the story. As this is written, the Met Office has flagged the largest El Niño event in over a century developing across the Pacific, with knock-on effects expected to bring wetter, stormier conditions to the UK this autumn. The September forecast is incredibly variable. Another possible late-season heatwave is forecast in the south, alongside a “more changeable”, wetter picture developing in the north.
These contrasting forecasts appropriately encapsulate 2026. There was not only more heat, but bigger swings. We had a drenched winter followed by a scorching summer, with an autumn that could bring both. That volatility is what the roofs of the future need to be built for.
The research
In the 2021 Future (P)roof research, James Patrick and Manfren Massimiliano identified overheating and flooding as the two greatest climate risks facing UK buildings. It found that loft conversions, flats with restricted ventilation, and buildings like schools are particularly vulnerable to overheating. It also showed that well-insulated, well-ventilated roofs with medium or light-coloured surfaces measurably reduce heat gain, and that cool, green and blue roof systems consistently outperform conventional dark roofs across every UK region tested.
On rainfall, the research warned against relying on historical data. A “1-in-100-year” event does not actually mean once a century. Changing climate conditions will likely make such events more frequent and more severe. Roof drainage, from outlet sizing to gutter access, needs designing around future risk, not past averages.
Compliance and resilience
Five years on, some progress has been made. Part O now addresses overheating in new residential buildings, and NFRC’s 2025 paper, Climate-Change-Ready Rooftops, has built the case for treating roof space as active climate infrastructure, capable of cooling buildings, managing stormwater and generating renewable energy simultaneously. But the Climate Change Committee’s 2025 assessment still rates policy on building overheating as “Limited”, and Part O doesn’t touch the millions of existing buildings that will remain in use for decades to come.
A roof fitted or refurbished today could easily still be in place in the 2050s facing conditions nothing in its original design brief anticipated. Compliance with today’s minimum standards is not the same as resilience to tomorrow’s weather.
What can be done
Addressing this doesn’t require exotic technology. It means treating refurbishment as a chance to improve thermal performance and drainage capacity, not just make good. It means checking that gutters, outlets and overflows are sized and accessible for heavier rainfall, not historic averages. It means considering roof colour and ventilation on any project with overheating risk, and flagging the opportunity for solar, green or cool roof systems where they fit. Making clients aware of these options is a critical first step.
Above all, it means treating climate resilience as a normal part of the design conversation, from the very beginning.
* This article was written in August 2026, ahead of its September publication. Some of the forecasts referenced below may have already changed by the time you read this. That, in itself, is the point!