tlee, what is that roof over top of? Are you experiencing any leaking?
I would suggest going to a commercial roofing supply house and explaining to them what your problem is. Most of your commercial suppliers have a large selection of could for specific applications. Asking for advise from the big box stores is probably not the direction I would steer you on a fiberglass roof deck. Thats something thats new to me in middle Tennessee. Stay away from silicone and roof cement though, just my :2cents:
Should be an easy job you could diy. Make sure everything is clean and dry before you repair.