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Re: GBlist: Re: Stucco

In a message dated 9/8/97 11:38:18 PM, you wrote:

<<A quick note on breathability and latex/acrylic mediums. I came upon a
reference for a european iaq research project that focused on mold
growth between layers of latex paint (bathroom area focus) and between
drywall and latex. Anyone familiar with this study or similar ones.>>


I got mountains of studies on fungal growth in my files, but not this one.
 I'd sure be interested in the study you recall.  I'm not familiar with that
study, but I have a fair amount of direct experience growing and dealing with
mold and a fair amount of training in indoor biology.  Mold, like any living
creature is looking for food, water, shelter and a way to make babies (mold
is a bit more broad minded about reproductive methods than mammals).  For
food it needs carbon, but has evolved to get rid of cellulose and lignin -
old plant stuff.  For water it needs a material to grow on that contains 65%
or more the amount of water it takes to saturate the material.  Latex paint an
d the paper covering on wallboard are good sources of carbon.  I find viable
mold spores everywhere I sample, unless the surface has been sanitized.  All
it takes for fungal growth in latex paint or wallboard covering is enough
water to get to the needed water activity in the material.  So bathroom walls
are good locations.  In cooling mode, particularly if the house is running
negative, the inner paper layer sheetrock beneath the paint is a good
location for moisture accumulation by condensation, doubly so if there is
vinyl wallpaper.  In heating mode the same dynamic makes a good habitat for
fungi in the outer stucco layer of the exterior walls, especially if the
house is running positive.  These problems are more likely in areas where
there is a lot of moisture in the outdoor air, like the coastal states, or in
sampwy microclimates.  The biggest, most difficult to deal with fungal
problems I've encoutered always seem to be in places with names like - Beaver
River, Nine-Mile Swamp, and Buzzards Bay.  In these places the mold grows on
everything inside and out.  In places where they get 7 inches of rain a year,
it takes a special coincidence of events to make a habitat for mold.  

Jeeze, I kinda rambled on being professorial.  Well, take what you like and
leave the rest.  

Warm regards,

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