Summer Flat Roof Maintenance Tips

While winter weather gets most of the attention when it comes to flat roof maintenance, summer presents its own challenges. UV radiation, thermal movement from heat, and intense storm rainfall can all affect flat roof performance.

UV and Heat Exposure

Felt roofing is particularly vulnerable to UV degradation. The surface mineral aggregate helps, but older felt membranes will crack and split as they become brittle with age. Modern systems — EPDM, GRP, and single ply — are far more UV-resistant.

Thermal Movement

Flat roofs expand and contract significantly with temperature changes. In summer, dark-coloured membranes can reach 70–80°C on a hot day. This thermal cycling puts stress on joints, flashings, and upstands. If your roof is on the older side, these are the details to inspect in spring.

After Summer Storms

Summer convective storms can deposit significant rainfall very rapidly — sometimes more than the drainage system can cope with in short bursts. After any severe storm, check that all drains are clear and that no debris has been deposited on the roof.

Summer Maintenance Checklist

• Clear any winter debris and moss from the roof surface
• Check drains and gutters are clear
• Inspect flashings for any movement or lifting caused by winter temperature cycles
• Look for new blistering or cracking in felt roofs
• Check condition of any sealants — these deteriorate faster in UV than the membrane
• Treat with biocide if moss or algae has returned