Water, Mold, & Building Materials

Building Science Corporation is a credible resource with unbiased factual information.
BSI-027 is a fascinating examination of the prevalence of microbial growth in new buildings. This excerpt is interesting and the photographs included in the article are truly remarkable.

“Mold is pretty easy to understand. No water no mold. Any questions? Well, there are a few. For one we have more mold today, but we don’t have more water. What’s with that? We’ve always built outside out of wet stuff. Concrete comes in a big truck and we “pour it.” We put “mud” in the joints of gypsum board. That hasn’t changed. The problem is that the same amount of water we’ve always had to deal with is hanging around longer and longer in building materials that can’t take it. We have more insulation today and that reduces drying potentials because it reduces energy exchange. That is one reason we have more problems with mold today. The “more insulation” is responsible for the water “hanging around longer” part. But there is another reason—the building materials “that can’t take it” part. We used to build out of rocks and 1,000 year-old trees. Not any more and that is a big deal, as we will see.

From an engineering perspective all that mold needs is carbon—to boldly go where no mold has gone before and seek out and find carbon. But it wants the carbon in a very special form—it wants it in the form of sugar. So, all the mold wants is the carbon in sugar. Now, we don’t talk that way because we don’t want civilians to catch on. We say that mold wants the carbon in a glucose polymer called cellulose—it makes us sound smarter. So where is all the cellulose? It’s in the plant kingdom. So, all the mold wants is the carbon in the cellulose in the plant kingdom. Pretty easy so far. But there are certain rules that the mold has to follow—one of which is that the plant has to be dead first. So what do we build out of? Naturally, dead plants.1″