*PLUMBERSSTOCK EXPERT* responded:
Hi there! Thank you for posting your question here on PlumbersStock.com concerning the Hercules 25405 Roof & Flashing Sealant. We are looking into the compatibility of this product with epdm rubber, in the meantime, if you need to order a product sooner rather than later you may contact our Customer Service Department at 435-868-4020 between 8:00 AM and 7:00 PM MT or through e-mail @ firstname.lastname@example.org. They can help you order the Geocel GC55101 (white) or the Geocel GC55103 (Black), both of which are designed to be used on Asphalt shingles, steel, concrete, EPDM membranes, tapes, patches, primed TPO, primed PVC, Hypalon (black only), metal, wood, and other common building substrates. We thank you for choosing PlumbersStock.com. Have a wonderful day!