Is it mold or algae ? I frequently see "green growths" on vinyl sided
houses around here [SC]. It's been so wet and humid here that even
part of our newer [~5 years old] pressure treated deck started to sprout
some green tinges.
Regarding the paint - I wonder if it is because it is latex paint (?) that
you start to see some mold/mildew ["SC's State Flower"] ? I also wonder
if an oil-based paint would have the same problem ? I suspect it would
be less likely. That may be the difference ?
Cheers,
Norm/mezmo