In my last blog I described the three elements that mold, like the rest of us, need to grow. The elements are reasonable temperature, food and water. In most cases temperature is a given and food is available. So the limiting factor is often moisture.
Mold does not need liquid moisture. Liquid moisture is essentially 100% relative humidity, like when water condenses on your air conditioning coil because it has reached the dew point. But some molds will grow fine at about 70% moisture activity, which is well short of liquid water. This is why we often focus our attention on spaces where there may not be liquid water but where the relative humidity reaches above 70%. The two most famous spaces are basements and crawlspaces. [Read more…]