Mold? on Siding


Old 03-02-09, 12:20 PM
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Mold? on Siding

Live in Central Florida and two years ago finished putting Hardie Siding on an out building (50X30).

Used two coats of top of the line paint from Lowes on top of the "pre-finished" siding.

I now have green stuff (mold?) slowly coloring the "shady" side of the building......The sunny side is fine....

What did I do wrong, and if nothing, is there anything to solve it from returning.

Have washed it twice, but it keeps coming back....

Thanks for any insights.
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Old 03-02-09, 04:47 PM
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That is normal for your location. I used to have a MH outside of Orlando. While the whole MH exterior only needed washing every 3-4 yrs, the north side needed washing twice a year. The dew gets on the siding but because the sun doesn't hit the north side, it's slow to dry which makes for optimal mildew growth

Next time you paint, add some extra mildwcide to the paint - it will help some.
Old 03-02-09, 05:08 PM
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To delay the return of mold, scrubbing the siding with TSP or Borax laundry detergent is often recommended. The detergents contained in these products contain surfactants that help resist the growth of mold. But as Marksr stated, some mold growth is normal and you'll have to keep after it.

This source contains some reasonable steps one can take when dealing with mold. You could skip down to #13.

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