Is Liquid RV roof compatible with Royal Roof tm. EPDM rubber sheet? It is on a 1999 Forest River Wildwood 25' 5th wheel. I called Rorest river they told me it was a EPDM rubber roof. Also wanting to find out correct way to prep, 4" Eternalbond seam tape that I used to repair small tears on edges. I understand it needs to be sanded and coated with contact cement , would sanding and then coating with proflex primer work ? Or would I need to sand ,contact cement then proflex prime ?