I live in Florida. I have a case against my homeowners' association where they have accused me of not cleaning the mildew off my home's roof. I used a bleach solution which I thought did a good job of cleaning off the discoloration. I initially did not want to hire a professional for I was told that pressure cleaning the roof could lead to damage to the roof's titles, decreasing the life of the roof. I have a roof made of tiles like the ones used up North..I can not think of the name of the tiles. Anyway, is there anything that can discolor a roof yet not be mildew? If I do decide now to hire a professional pressure cleaner, how should they determine what to clean the discoloration off the roof with? Thanks for your help.