Epdm rubber roofing has splice adhesives and tapes. Both require a primer first. The temperature requiremens should not be an issue. I would be more concerned with the stability characteristics of EPDM. It has quite abit of movement. Contact a national low slope roofing supplier like ABC Supply...
Is it possible to build...a polymer/plastic (possibly of recycled material) box with inside measurements that are 34" wide by 90" long and 32" deep. The frame/skeleton preferably would add less than an additional 3 to 5 inches to the overall. It needs to withstand a gradually increasing top...