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THE MOLD CONTROVERSY (cont'd)

Problems In New Construction

One might wonder, “Why do we hear so much about mold these days and not in the past?” The answer is not an obvious one, but a short history lesson will help highlight the answer for you. Before the Arab Oil Embargo of 1973, and for decades before this, many painted interior walls were constructed of wooden lathe (thin wooden boards) and a mortar mix, which contained antifungal properties. Those kinds of painted surfaces were resistant to mold. Many houses, particularly the older ones with wooden sliding windows, were also somewhat drafty, which led to many fresh air exchanges during the day.  

But after oil prices soared in 1973, the building industry began looking at more energy efficient methods and materials. This was a natural response to market factors as people wanted houses that did not cost so much to heat. The result was more energy efficient homes, tighter windows, the use of sheet-rock or drywall and OSB plywood. These “good cents homes” were less drafty and more energy efficient. But this move to new materials led to lower indoor air quality. Ironically, the drafty old houses were healthier because they exchanged the air from the outside around the clock. But alas, it turns out that mold, particularly the marker taxa molds that have been implicated in SBS love drywall and oriented strand board plywood (OSB).

Builders have also cut corners to save money. Instead of installing flashing around windows, they simply put on trim and a bead of caulk. But caulking fails and dries out over time and windows without flashing will eventually leak. According to a recent ABC news report, complaints regarding new homes to the Better Business Bureau have doubled in the last five years. Mold, which appears in many of those complaints, has become more of an issue in recent years due to new building materials and processes. The manufacturing techniques used to produce materials such as OSB plywood also bring more molds into the structure from the beginning. Dormant and isolated mold spores can be impregnated into these materials in the manufacturing process, then become active when these materials get wet. This happens frequently during the building process, which has become year round in many parts of the country. Energy conservation codes have also led to the construction of homes that are unable to breathe and dry. Therefore, once water is trapped, mold has the conditions it needs to flourish.

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