Summer 2026 is on course to be the UK’s hottest on record, but while homeowners focus on keeping their properties cool, prolonged heat and sunlight may also have caused damage that could become more apparent when autumn rain arrives.
According to provisional Met Office figures released in mid-August, the UK mean temperature for meteorological summer up to 10th August stood at 16.48°C, nearly 1.9°C above the long-term average. Only near-average conditions for the rest of the month would be needed to surpass the previous record set in 2025.
England and Wales have experienced even stronger warmth, with multiple heatwaves, temperatures reaching 38°C in June, and the first year on record to reach 35°C in May, June, and July.
Repeated exposure to high temperatures can put additional stress on roofing materials, insulation, seals, and other parts of a home. Roofing experts say the expansion and contraction caused by hot days and cooler nights can accelerate wear and potentially contribute to leaks when wetter weather returns.
According to roofing and insulation expert Mike Storey of UKFR Roofing & Insulation, homeowners should look out for four signs of possible heat damage.
Cracked or split roofing materials
Repeated heating and cooling can cause roofing materials to expand and contract, placing additional stress on components that may already be deteriorating.
Homeowners should check for visible cracks, splits, or deterioration, particularly around roof coverings, joints, and seals.
Storey said: “We’ve had a long period of very hot weather this summer, and it’s the repeated exposure that’s important rather than just one particularly hot day. Roofing materials expand when they’re heated by the sun and contract again as temperatures fall overnight. Over time, that movement can put stress on materials, particularly if they’re already starting to deteriorate. If you can see any cracking or splitting on your roof, it’s worth getting it checked rather than assuming it’s just cosmetic.”
Blistering or bubbling on a flat roof
Flat roofs can absorb significant solar heat throughout the day, making blistering or bubbling on the surface a potential sign of damage after prolonged hot weather.
Blisters or bubbles can indicate that the roof covering or underlying layers have been affected. Industry guidance highlights that bitumen and rubber membranes are particularly prone to these changes under intense UV exposure and heat.
Storey said: “If you’ve got a flat roof, take a look at the surface and see if anything has changed over the summer. Blistering, bubbling or areas where the surface looks raised aren’t things I’d ignore. They can be a sign that the roof covering has been affected by prolonged heat, and if water gets into those areas later on, you could end up with a much bigger problem. It’s much better to sort these issues now, while the weather is dry, than wait until the autumn rain arrives.”
Deteriorating seals around roof windows, vents or other fittings
Strong sunlight and high temperatures can affect seals and other components around the roof.
Homeowners should look for cracked, dried-out, or deteriorating sealant around roof windows, vents, flashing, and other roof penetrations. Once a seal begins to fail, water can enter the property when wetter weather returns.
Storey said: “People tend to think about the roof covering when they’re looking for damage, but some of the smaller components can be just as important. If you’ve noticed cracking or deterioration around a roof window, vent or another fitting, it’s worth getting it looked at before the rain returns. A small problem with a seal can become a much bigger problem if water gets underneath it.”
Insulation that has become compressed, moved or deteriorated
Heat-related problems may not always be visible from outside the property. If rooms that previously remained comfortable have become significantly hotter, homeowners may want to check their insulation as well as the roof.
Insulation can deteriorate or become displaced over time, reducing its ability to regulate indoor temperatures. Poor loft insulation is a known contributor to excess heat gain in summer as well as heat loss in winter.
Storey said: “Insulation isn’t something most people think about when they think of summer damage because you can’t normally see it, but it’s an important part of how your home handles extreme temperatures. If you’ve noticed that a particular room has become much hotter this summer than it was in previous years, I’d be looking at the insulation as well as the roof itself.”
Check before autumn rain arrives
Experts recommend inspecting roofs and related components while dry conditions persist, ideally before the weather turns. Identifying heat-related wear early could help prevent water ingress and more costly structural problems later in the year.
For more information, visit UK Flat Roofing.