Such materials as wallpaper paste, paper, fabrics, skin cells and wood are some excellent sources of food for mold. Molds can be found growing on drywall, carpet backing, wood structures, furnishing and clothing. A misconception about mold is that it needs to have a dark environment in which to grow, such as a closet or basement. The reason it seems to grow faster in these areas is because there is less air movement to dry out residue moisture in the walls or moisture which has condensed on building surfaces and on clothing. In addition, the growth in these areas is not as noticeable to the resident as in the more frequently used areas of the house.
Mold needs water to grow.
Water intrusion into the building structure from rain, irrigation systems and plumbing leaks are common sources of water intrusion. Defects in the construction of a building water proof system may allow water into wall cavities around windows, doors, balconies, and exterior fixtures to name a few. Once the water is trapped inside a wall cavity and not dried out within 24-48 hours, it can cause mold to grow. Another water source is condensation from an elevated amount of water vapor in the air condensing on building surfaces and wetting them. Water vapor inside a home can be caused by the water intrusion as described above evaporating inside wall cavities and building structures.