18 | July 2019
les' heels when it comes to mold infestation. Gypsum wallboard, cellu-
lose-based ceiling tiles, insulation and fireproofing materials are some of
the products that often fall prey to mold attacks.
Wet It, and They Will Come…Sooner
If there is one underlying issue in this mold/microbial mayhem, it's the
moisture. Spores are everywhere: in building materials, in our furnish-
ings, on our indoor surfaces, and even in the air. Our dwellings and
their contents are potential food sources for these microbes because
they are largely comprised of organic materials. Fungi and bacteria do
not grow in the air; they grow on environmental surfaces. These are
universal truths. Why, you may ask, do only some buildings become
infested with mold or other microbial contaminants? What should be
the obvious answer is, of course, moisture.
Typically, fungus growth requires an environment with a water activi-
ty (represented by the acronym—A
w
) of greater than 0.7 at the surface.
A material with an elevated moisture content (MC) will often provide a
suitable surface A
w
to promote microbial growth.
Post Hurricane Katrina mold damage in New Orleans
apartment —Photo by IAQ Technologies
Close up of mold growth on interior wall —Photo by
IAQ Technologies
Mold growth on fan
in flood-damaged
home — Photo by
IAQ Technologies
