UNDERSTANDING WATER DAMAGE RELATED MOLD, MILDEW & FUNGUS
by Claude Blackburn
One of the reasons for drying water soaked carpets, structural materials and contents is to prevent permanent damage caused by fungi and bacteria. Saprobic fungi (which includes mildew and molds) and bacteria are responsible for decomposition of all organic material. Under the right conditions fungal spores germinate and form hypha. During this process the spore absorbs water through its wall, the cytoplasm becomes activated and division takes place. The growing tip of the hypha eventually branches out. This is the begining of the mycelium. Growing tips that come in contact with other hypha often fuse with them to become a hyphal net.
Mildew is the mass of threadlike hypha and fruiting structures produced by various fungi in the division mycota. The mildew we deal with is caused by one of 50,000 species of saprophytic fungus that lack chlorophyll and feed off dead organic materials. Since fungi possess no chlorophyll, they cannot photosynthesize, and they obtain their carbohydrates by secreting enzymes into the surface on which they are growing. The enzymes digest the food, which is then obsorbed directly into the hyphal walls of the fungi. Generally acid growth substances are needed as a food source. Saprobic fungi utilize most types of organic materials such as lignin, cellulose and other polysaccarides.
Fungus spores are everywhere and are just waiting for the right conditions for growth in every structure. Studies have shown that most mildew is mesophilic, that is it grows between 69 and 86 degrees. Most mildews will not grow where it is colder than 65 degrees or warmer than 115 degrees fahrenheit. Mildew also prefers an enviroment that is damp and dark. It is intresting to note that it does not grow well where there is good air ventilation. (A good reason to use Turbo Dryers.) Another Characteristic of most mildew is that it won't grow when totally submersed in water. Mildew and other fungus spores are present in every structure, Yet they usually remain in a dormant state when materials are dry and the humidity is below 60% RH. They quickly become active when organic materials become damp and/or humidity increases above 60%RH.
Most likely you've seen the affect of fungus growth many times. A walk through a forest attests to the power and rapid growth of fungi on wood materials. A fallen tree soon decays and returns to the soil. Moss usually grows on a tree in the shadow of the wind. A mailbox post must be treated with wood preservative to retard the growth of fungi. Fungus feeds and grows on the grout between the tiles from moisture and humidity. Even cedar, the most resistant of woods, becomes a home for fungus on roofing shakes. And the growth is usually more pronounced on the more shady/windless side of the home.
In an indoor flood situation, mildew grows on cellulose carpet fibers such as jute, wool, rayon, and cotton. It can even thrive on the organic materials in carpet adhesive. It can also attack the paper materials in drywall and even wood materials including framing, floors, walls tackless strip. Mildew cannot "feed" on synthetic materials such as nylon, polyester, acrylic or oilfins. Yet you may see mildew on these materials if there is sufficient organic material (soil) to support growth. When mildew is active, it can damage carpet adhesive jute backings, while being hidden from view by the synthetic face yarns. With time it can even weaken framing materials and destroy drywall while invisible behind the wall. Therefore it is prudent to treat wet materials as if mildew was already present.
When dis-engaging water damaged carpet look for previous mildew damage. This is most common around bathtubs, showers, toilets and sliding glass doors or where there has been a slow leak. Mildew usually appears black and feels sooty. It gives off gaseous odors when it is active. This gas is carried by high humidity to all parts of the home or business. It is not always easy to determine when mildew is present because it can remain dormant for long periods without releasing its gaseous odor. When the right conditions are introduced, it can once again become active. Deflooders must understand mildew or eventually get into trouble. It is vitally important for you to evaluate the potential for mildew growth and damage during the emergency service call.
Most fungi can be destroyed using a strong enough concentration of an antimicrobial deodorizer. Affected materials should be treated on the initial service call while the materials are still wet. Materials can be treated again after the initial extraction and even once again before and/or after the cleaning process. Yet the most important treatment is the initial one.
"You've made the right call"
SERVICES & RESTORATION"
Untreated water damage
Mold & Mildew
attacking a home's
over 5 ft. wide and 8 ft. long, 2 inch.
thick. It had consumed a rat
Photos by Kevin Benson