Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture.
Most mold starts from a water intrusion problem. Whether it be a plumbing or roofing leak, mold is generally caused by moisture that has not dried properly. In a recent case study, over 500 homes that had a mold problem began with a water intrusion problem.