Hey guys what should I use to seal the bottom side of my deck. The top is trex and the bottom looks like pressure treated wood. I dont know when this was installed but I pressure washed it clean and it has dried for the past two days... The guy at the paint store told me to buy wolmans raincoat water-based (blue can). Is this good for this project? What is the difference with oil-based, there seems to be much more oil based products out there. Is there a better product or is the wolmans water based ok?