How does mold spread in your home?

For molds to grow and reproduce, they only need an organic food source, such as cellulose, which is found in building materials such as wood and drywall. The amount of moisture in these materials influences how an organism can support growth. Moisture sources would include condensation in humid rooms, on windows, unheated closets, dampness under carpets and on shower curtains, and periodic wet sections in ductwork of air conditioned ventilation. Temperature is also a factor that affects mold growth. Molds typically require temperatures between 5°C and 38°C to grow.