We have a tiled ceiling on our front enclosed porch. It's looking a bit dingy/gray and slightly warped, but at this point I don't want to deal with replacing it. Since I'm going to be painting the walls, I would like to just paint the ceiling too so it looks a little brigher. I've heard that tiled ceilings tend to absorb a lot of paint and multiple coats maybe needed...is this true? Should I prime it? Or is there special paint I should buy? Thanks!