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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. |
