Can you fit an EPDM rubber roof in autumn or winter?

Lots of flat roofs fail in autumn, and it's natural to want the new roof on straight away. You can fit an EPDM rubber roof outside summer. The membrane itself doesn't mind the cold. The adhesive does, and that's what decides whether you can work on a given day.

The short answer

Yes, on the right days. You need a dry deck, a surface temperature above about 5°C and rising, and no frost or heavy dew while the adhesive cures. In a UK autumn that usually means a few good days a week, with a working window of late morning to mid-afternoon. In midwinter there may be weeks with no suitable days at all.

Why temperature matters so much

EPDM roofs are held down by adhesive, and both common types are affected by cold:

• Water-based deck adhesive, used across the main area of a timber deck, has to lose its water to bond. Manufacturers' data sheets say not to use it below about 4–5°C, or if frost is forecast while it cures (allow 24 hours). Frost in the adhesive ruins the bond.
• Contact adhesive, used around the perimeter and on upstands, has to flash off before the surfaces are pressed together. In the cold it takes much longer to go touch-dry.

There's a hidden problem too. As adhesive dries, it cools the surface. On a damp autumn day that can drop it below the dew point, so condensation forms on the adhesive. If you see a milky film or beads of water on adhesive you've just applied, stop. Let it dry and re-coat it. Laying the membrane on top will leave blisters.

How to plan a cold-weather EPDM job

1. Watch the forecast, not just today. You need the day you lay it and the night after to be dry and frost-free.
2. Start once the deck is dry. Morning dew can take until late morning to clear. Run a hand over the deck. If it's cold and damp, wait.
3. Keep materials warm. Store adhesive tins and the membrane indoors overnight. Cold adhesive is thick and hard to spread evenly.
4. Give the membrane longer to relax. Unroll it and leave it flat for longer than you would in summer, so the creases drop out before you bond it.
5. Do one section at a time. Only apply as much adhesive as you can cover before the light or the temperature goes.
6. Stop early. Don't start a new section in the last couple of hours of daylight. The temperature falls fast and the dew comes back.

What if you can't wait for a good day?

If the roof is leaking now and the weather won't let you re-roof, make it watertight and do the full job in spring:

• Patch the leak. A cold-applied butyl tape like Supraseal® Black seals splits, failed laps and leaks at upstands without any adhesive to cure. It still needs a dry surface, but it doesn't need a run of dry nights. See how to repair an EPDM roof with tape and our guide to applying tape in cold or wet weather.
• Cover it. If the existing roof is beyond patching, a well-secured tarpaulin buys you time. Weigh it down rather than fixing through the deck.
• Order in good time. Get your membrane, adhesive and trims on site before the weather window, so you're ready the moment it arrives.

Get the materials ready

Supraseal supplies ClassicBond® EPDM cut to size, plus the adhesives, trims and corners the job needs. Price your roof with our EPDM roof calculator or see our ready-made kits. Before you start, read the EPDM installation guide.

Not sure whether your roof can be fitted now? Call Tom on 07949 862834 or email hello@supraseal.com. We supply materials only and don't install, but there's 20 years of roofing behind the advice.