This time of a year in the South, we experience very high water vapor pressures, manifesting itself by miscellaneous moisture problems of mysterious nature. Do you feel uncomfortable, your printers and copiers fail to print, envelopes glued themselves together, steel is covered with a thin layer of rust, wood delaminated and bowed, pests overrun the place, and the musty odor explains why your employees are on a sick leave?

There are many possible reasons, but this time we would take the vapor retarders under a magnifying glass. Why? Not just because of the steamy August behind our windows, but also because this subject is so simple and easy that it would make me look smart enough in comparison.

Have you ever wondered where the vapor retarder should be located? The answer is so simple, that it’s hard to understand why so many myths grew around this subject. Unlike air leakage, it’s easily quantifiable. However, unlike the air leakage, it’s hard to understand without elementary science education; which probably explains why architects fail so often and so miserably.We will quote some examples, but however funny architectural goofs may sound, the troubling part is their role models don’t do much better, as illustrated by examples from architectural education.

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