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Ask the Expert Question-and-Answer Archive by Ron Joseph May, 2005 Painting Steel Q. We're considering a design for a steel frame house in a flood zone (VE-14) rather than wood piles. Our choice is to use galvanized steel which will need to be shop fabricated and then dipped or using non-galvanized, but shop primed steel that can be field fabricated. We could then paint the entire steel frame, but I need some coating that will withstand the corrisive salt air of a marsh front lot in Charleston, SC. Any recommendations? A. There several options depending on how much you want to spend and how critical corrosion is at the site. The ultimate corrosion protection from a coating system can be accomplished by abrasive blasting the steel and applying an inorganic zinc-rich primer. This coating is best applied by a qualified industrial contractor who has done this before, not a conventional house painting contractor. The next choice is to abrasive blast the steel and apply a conventional zinc chromate primer. This might do the job well, but it does not equate to the zinc-rich primer. In either case you can apply an epoxy coating over the primer followed by a decorative topcoat. Decorative epoxy coatings are not recommended for exterior exposure (to sunlight) as they tend to chalk. If you are interested in pursuing the first option, we will be happy to assist you in writing the application specification. Best wishes, Ron Joseph |