I recently had the flat-roof portion of my house done in EPDM. They laid new sheathing (ply) and put the EPDM over that. I've noticed that some of the nail heads from the plywood are actually sticking up underneath the EPDM. I'd say the nail heads are approx 1/4" higher than than the surface of the ply. The EPDM is raised in little bubbles (for lack of a better term) where the nails are.
Before I bring the roofer back, I wanted to check with some people who know more about this than I do. Will that cause stress to the EPDM & cause problems? Can they simply be hammered down or do they need to strip & relay the roof?