If an EPDM rubber roof, it is highly recommended that you be very careful what you use. Dicor, the rubber roof maker, requires the primer first that the initial poster stated. Liquid Roof has a catalyst included that you mix in the coating before applying. Lowes is carrying a "50 year silicon coating" for rubber roofs. There is a guy here in Yuma, AZ. applying this product. I've looked at several he has done. It puts a great looking coating on the roof. So I am getting ready to do something with that PITA up there. I looked the product up on the inet and in the fine print and download that says "if coating a EPDM roof a different procedure must be used. So I emailed the outfit and there answer was " a primer must be applied before using our coating. We don't have a primer but recommend a Dow product. So I email Dow, "yes that product is the primer but it available only commercially". Now if the RV was permanently parked I would have no trouble using a product that requires no catalyst or primer. But this rig rolls up and down the roads, so I don't want to waste time and money on a product that will peel off. I just hate the thought of tarping the sides of the RV to protect it when hosing the primer off.