EPDM Flashing Tape

EPDM flashing tape is what turns a sheet of rubber into a watertight roof. The membrane itself does the easy part — covering the flat area. The tape does the hard part: sealing where the roof stops, turns, or is interrupted by something.

Self-adhesive flashing tape bonds cold, with no torch and no hot works, which is what makes EPDM viable as a DIY material and safe on a roof attached to a building. It is used to dress upstands where the roof meets a wall, to seal laps where two sheets meet, and to weather the awkward junctions around kerbs and abutments that no flat sheet will sit into.

Two things decide whether tape holds. The first is primer: EPDM carries a factory film of talc, and tape applied over it will lift within a season. The second is pressure — a seam roller worked firmly along the tape, not thumb pressure. Get both right and the seal outlives the building. See our guide to EPDM flashing and detailing for the full method.