make the Cage out of melamine wood. It's like what countertops are made of, it will have the water proof coating just like a countertop and works great! However it is a little heavy and made of particle board, so you would not want any water to get on the wood itself or else it could puff up. Basically just make sure you caulk the edges up good! I used this and it's perfect since it doesn't require painting (unless you want it a different color other than black or white)