The reason I wanted to use a water based is because it is 7000 square feet and if I use an oil on the water damage I have to use an oil on the whole job, and I prefer water based. As far as I know, and correct me if I'm wrong, it isn't a good idea to use a oil primer with a water topcoat.ProWallGuy said:Not too keen on using water-based for water stains. I have used Zinsser's GARDZ on occasion and it worked, but there were only small spots. The HD says Kilz2 will cover water stains, but....it is HD after all. Kilz2 is worthless IMO.
cool. yea I never even thought to wash it down. Thats a good idea.ProWallGuy said:If the stains aren't too dark, I'd try to wash them down with a bleach solution (if feasible), and coat it with B.M. Freshstart or Perter's BlankIt. Both are acrylic, and have an ammonia odor, but cover well.
Exroadog said:"very old interior plaster" if it has never been painted, your best off with oil primer. Then finish with latex.