by Ron Joseph
November, 2005
Painting Over Concrete When Salt is Present
Q. I have a concrete building that is two blocks from the ocean. The humid on-shore
breeze brings salt with it. To make matters worse, I suspect unwashed beach
sand was used in the concrete when the building was constructed. Not surprisingly, the paint on the walls begins to bubble and peel after
about six months. It's worst if oil-based paint is used, and in that case the
paint also starts to re-liquify (paint will come away on your hand if you press
it to the wall).
Is there anything I can do to address this maintenance nightmare?
A. Unfortunately the damage is done and the only remedy I can think of is to
strip the coatings, thoroughly power wash the walls, possibly also scrub the
walls to remove the salt contaminants and start again. If you paint over the
old paint you will simply make the mess even worse.
Sorry for the bad news, but I suspect you know this already.
Best wishes,
Ron Joseph
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