Any thoughts on Waterproof paint?

[Bruce Woodruff]

I'll be moving into a new house that has an outdoor patio, with misters. The current drywall ceiling has blistered paint. Rather than installing T&G (my first choice), I think I will just get it painted with some good water 'proof' paint for the time being. I'm thinking even rubber based. Does anyone have any experience with such a product. I know it exists for decks, but for use on drywall, I'm not so sure.....?

[Ryan Normand]

I haven't heard of anything quite like you're describing, but in general I always tell people to use a higher sheen whenever moisture is present. In your case I would just prime the whole surface with an all purpose primer (e.g. Kilz 2) and then do at least 2 coats of a high quality exterior paint in either semi-gloss or satin. It might show imperfections in the ceiling more than flat paint, which is probably what's on there now, but IMO it's worth it for the durability. 

Like you, drywall on the lid of an outdoor patio isn't my first choice either. I see issues with it all the time, even in PHX where it's hot and dry all year round. I'd much prefer v groove or T1-11/LP Smartsiding.