| Poor Alkali Resistance: Color loss and overall
deterioration of paint film on fresh masonry.
Possible Cause:
Oil-based paint or vinyl acrylic latex paint was applied to new
masonry that has not cured for a full year. Fresh masonry is likely to contain
lime, which is very alkaline. Until the lime has a chance to react with carbon
dioxide from the air, the alkalinity of the masonry remains so high that it can
attack the integrity of the paint film.
Solution: Allow masonry surfaces to cure for at least 30 days, and
ideally for a full year, before painting. If this is not possible, the painter
should apply a quality, alkali-resistant sealer or latex primer, followed by a
top quality 100 percent acrylic latex exterior paint. The acrylic binder in
these paints resists alkali attack.
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