[villagetinker]

OP, you should probably plan on having the original paint completely removed (sandblasting or grinding), while this is costly, you will get a better job. From recent experience, we had the lanai repainted to match what we were doing in the new birdcage. I specifically asked if the now paint could be applied over the existing paint and was told yes. Well he was correct, EXCEPT the original paint has started to fail, and of course the new paint is now flaking off. Not sure how we are going to fix this.............