4197015Mold Web Course — Lesson 2: What Mold Needs to Growthe Environmental Protection Agency
Lesson 2What Mold Needs to Grow
To grow indoors, mold needs moisture and food. Moisture is the most important factor influencing mold growth indoors. Controlling indoor moisture helps limit mold growth.
Moisture control is the key to mold control.
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Mold does not need a lot of water to grow. A little condensation, in a bathroom or around a window sill, for example, can be enough. Common sites for indoor mold growth include bathroom tile and grout, basement walls, and areas around windows, near leaky water fountains, and around sinks. Common sources of water or moisture include roof leaks, condensation due to high humidity or cold spots in a building, slow leaks in plumbing fixtures, humidification systems, sprinkler systems, and floods.*
Besides moisture, mold needs nutrients, or food, to grow. Mold can grow on virtually any organic substance. Most buildings are full of organic materials that mold can use as food, including paper, cloth, wood, plant material, and even soil. In most cases, temperature is not an issue; some molds grow in warm areas, while others prefer cool locations such as bread stored in a refrigerator. Often, more
than one type of mold can be found growing in the same area, although conditions such as moisture, light, and temperature may favor one species of mold over another.
*Floods
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Buildings that have been heavily damaged by flood waters should be assessed for structural integrity and remediated by experienced professionals. Please note that the guidelines covered in this course were developed for damage caused by clean water (not flood water, sewage, or other contaminated water). See the EPA Resource List, which includes the EPA Fact Sheet: Flood Cleanup - Avoiding Indoor Air Quality Problems, for more information.
