What causes relative humidity damage?
We’ve all suffered through muggy, steamy summer days. Humidity, or the amount of water vapor in the air, can be measured in several ways. Relative humidity (RH) is a measure of the amount of water vapor air holds at a given temperature. Regardless of temperature, too high, too low, or fluctuating levels of RH can damage artifacts in our houses and museums. High RH causes mold, mildew, and fungal growth, as well as swelling, rusting, and corroding. Low RH causes cracking, shrinking, drying, desiccation, and brittleness. Fluctuating RH causes swelling and shrinking; over time, the lifting and peeling of surfaces and structural weakness.
