Frequent Causes of Mold Growth

10 Mold Facts for Homeowners, Landlords, Tenants, & Employers

1. Airborne mold spores are everywhere both indoors and outdoors. Resident and employee health is at serious risk if there are elevated levels of mold spores indoors, as compared to an outdoor mold control test.

2. The most dangerous indoor molds are Alternaria, Aspergillus, Chaetomium, Cladosporium, Fusarium, Mucor, Penicillium, and Stachybotrys. Mold testing and mold laboratory analysis are required to identify specific mold species.

3. Molds spores can cause serious health problems even if the spores are dead or dormant (inactive while waiting for more moisture to resume growth). Even the smell of dead or dormant mold can make some mold-sensitive persons ill.

4. It is impossible to get rid of all mold spores indoors. Some mold spores will always be present in house dust and floating in the air.

5. The mold spores will not grow into mold colonies if there is insufficient moisture.  Indoor mold growth can and should be prevented or controlled by controlling moisture indoors. If organic materials are wet for more than 24 hours, mold growth can begin.

6. Mold grows by eating and destroying organic building materials and other cellulose-based materials such as carpeting, upholstery, and clothing. The longer that mold grows, the more mold damage to the building.

7. Cellulose is the main substance in the cell walls of plants (and thus of wood), and it is used in the manufacture of many organic building materials such as drywall, plasterboard, plywood substitutes, and ceiling tiles.

8. Mold can grow hidden and undetected inside wall and ceiling cavities; beneath wallpaper, paneling, and carpeting; and inside heating and cooling equipment and ducts, attics, crawl spaces, and basements.

9. Mold growth is often the result of a structural or construction defect, or of maintenance neglect, that allows moisture to enter the building.

10. The owner or employer must first fix the water problem (roof leak, plumbing leak, high indoor humidity) that enables the mold to grow. Effective mold remediation requires killing the mold with an EPA-registered fungicide, removing it, and treating the cleaned area with an EPA-registered preventive fungicidal coating.