Whether you use an Alpha or Dicor, or some other EDPM roof coating, it will last longer and bond better if you use the proper primer. The primer chemically cleans and allows the new coating to better bond to the old, weathered surface. If you don't use the primer to save money and time, it will end up costing more in a year or two when you have to do the whole thing over due to a failing roof coating.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI