There are many coating systems that are designed for roof systems. Some we have already discussed at length. Make sure that the coatings have been designed for your particular system, and the roofing manufacture approves the coatings.
At this time, there are a couple of coating systems that we will not install. At this time we will not install a urethane roofing system either. These systems have been around for quite some time, and we have replaced a number of them. Unfortunately we have never seen any that have performed as advertised, and they are incredible expensive to replace.
Years ago Disney had a great many of their roofs covered with the coatings. It is my understanding that they have replaced all of them and do not use that system any longer. Many of our customers have had the same experience. Once the system is perfected and we can install one with a clear conscience that they will perform as advertised, I am sure we will install them also.