How would you react if I told you that your homes walls were virtually guaranteed to grow mold?
That for a portion of the year, the sheeting inside your wall will be wet?
Some of us may be too young to remember the black mold scares of the late 80’s and early 90’s that happened when builders began tightening their homes in response to tougher energy codes, new methods and products, and customer demands. Most builders have not completely addressed the root cause of these problems.
Mold is less of a problem because the codes and products have changed in response, but in the vast majority of new homes; it remains a threat.
You see; in the “good” ole days; the walls, windows, and roofs of homes were quite leaky. Most homes were not air conditioned. This meant that in the winter months, the warm, moist air would leak out, pulling cold, dry air in with it. Air flowing through the walls was very capable of drying out any moisture that had accumulated within the wall cavities. Since mold needs moisture to grow, it never had a chance in these leaky homes.
Problems began to arise when large amounts of insulation began to be placed in the walls. This slowed air movement, reducing drying. Compounding the problem was housewrap and OSB, which reduced air flow even more. Now a new problem presented itself: The cold exterior sheeting began to condense indoor moisture, just like a cold can of soda gets wet when you place it in a warm environment.
While there is a vast body of information on ways to address this problem, the simple fact is that most builders either are not aware of it, or don’t have an adequate solution. Their homes will have moisture condensing within the wall cavity for a portion of the year. Our winters have the greatest condensation potential, but summer conditions can cause condensation as well.
As this condensation wets the OSB and insulation, it causes premature failure of structural components of the home. It is also a key factor in the growth of mold. Just because you don’t see it, doesn’t mean you don’t have a problem.