Avoid Mold Hazards In Flood-damaged Home

Claudette Reichel, Merrill, Thomas A.  |  9/21/2005 2:13:55 AM

News Release Distributed 09/20/05

A flood-damaged home requires special attention to avoid or correct a "population explosion" of mold, says LSU AgCenter expert Dr. Claudette Reichel.

"Mold is likely to multiply on materials that stay wet for more than two or three days," cautions Reichel, adding this means many residents in storm-affected areas will face a problem.

"Even worse, the longer mold is allowed to grow, the greater the hazard and the harder it is to control," she says. "So as soon as floodwaters recede and it is safe to return, don’t delay cleaning up and drying things out."

The LSU AgCenter housing specialist says to take photographs to document damages for insurance purposes and then get started cleaning up as soon as you can return to your home.

"It is not wise to wait for the adjuster to see it in person," Reichel advises. "Most homeowners insurance policies do not cover mold damages or cleanup costs."

Reichel explains that exposure to mold – particularly in the long term – can have adverse health effects.

"Molds produce spores that float and spread easily through the air, forming new mold growths or colonies when they find the right conditions – moisture, nutrients and a place to grow," she says. "Although there is wide variation in how people are affected by mold, long-term exposure or exposure to high levels of mold is unhealthy for anyone."

Exposure to mold can trigger allergic reactions and asthma attacks, may suppress the immune system or have other effects, according to experts. Some types of mold also can produce mycotoxins under certain conditions, which can be present in live and dead spores and fragments in the air.

Although there can be problems from mold, the LSU AgCenter expert says mold testing usually is not needed and is rarely useful to answer questions about health concerns.

"Some insurance companies and legal services may require sampling as a form of documentation," she says. "And professional mold remediation contractors may test before and after cleanup to provide evidence of the cleanup’s effectiveness. But you don’t have to test just for the sake of testing."

To prevent mold growth after flooding, Reichel says to follow these tips:

–Remove wet carpeting right away. It’s best to discard it, but if you choose to salvage carpet, clean, disinfect and dry quickly with professional equipment or outdoors. Never reuse flooded padding.

–Cut away wet wallboard and remove all wet and damp insulation right away – even if wallboard appears to dry. Wet insulation will stay wet far too long, leading to the growth of hidden unhealthy mold and decay fungi inside the walls.

–Clean with non-phosphate detergents (any phosphate residue is mold food). If you disinfect, follow directions carefully and never mix bleach with ammonia or acids (vinegar). Disinfectants can kill molds, but they do not prevent regrowth.

–Do all you can to speed the drying of subfloors, slabs and wall framing before replacing insulation, wallboard and flooring. Use air conditioning or heaters, fans, and, better yet, a dehumidifier. Water damage restoration contractors with special equipment (dehumidifying blowers) can provide the fastest drying.

–Test the moisture content of studs and sheathing (using a moisture detector) before replacing insulation. Wood should drop below 20 percent moisture content by weight before you close the wall.

–Do not use vinyl wallpaper. It prevents further drying of the inside of the wall by blocking air flow.

Concerning how to clean up the mold that may already exist, the LSU AgCenter expert offers these suggestions:

Refer to the EPA guidelines that can be found in "A Brief Guide to Mold, Moisture and Your Home" or "Mold Remediation In Schools and Commercial Buildings," available online at www.epa.gov/mold.

–Minimize your exposure during cleanup. People are mainly exposed to mold by breathing spores or fragments, but you can also be exposed through skin contact. Wearing gloves and a respirator that can filter mold spores (N-95 or better) is recommended.

–Isolate work area and ventilate to outdoors. Disturbing mold colonies can cause a massive release of spores, so seal off the contaminated area from the rest of the house. If power is on, use a fan to exhaust air to the outdoors.

–Remove and discard moldy materials. Porous moldy or sewage-contaminated materials should be removed, bagged and thrown away – including gypsum wallboard, insulation, plaster, carpet/carpet pad, ceiling tiles, processed wood products and paper. To minimize the spread of spores, cover moldy material with plastic to contain spores before removing and discard it. Even if not moldy, all wet fibrous insulation and other materials that are unlikely to dry quickly enough should be removed and replaced.

–Clean surfaces. Surface mold on nonporous materials such as hard plastic, concrete, glass, metal and solid wood usually can be cleaned. Cleaning must remove, not just kill, the mold, because dead spores can still cause health problems.

–After cleaning, you may choose to use a disinfectant to kill any mold missed by the cleaning. In the case of sewage contamination, disinfection must be performed. Contact your local health department for appropriate advice. On colorfast, nonmetal surfaces, you may disinfect with a solution of 1/4 to 1/2 cup bleach per gallon of water. Do not use in the air system. Milder, less corrosive disinfectants include alcohols, disinfecting cleaners and hydrogen peroxide. Always handle with caution. Never mix bleach with ammonia, and test on a small area.

–Speed dry. Dry all wet materials as quickly as possible. Use air conditioning or heat with fans and dehumidifiers, if possible. New mold colonies can form in as little as three days if materials stay wet. Wood and other materials that may look dry can still be wet enough to support regrowth.

–Remain on mold alert. Continue looking for signs of moisture or new mold growth. If mold returns, repeat cleaning and consider using speed drying equipment and moisture meters. Regrowth may signal that the material was not dry enough or that it should be removed. Rebuilding should wait until all affected materials have dried completely.

For more information on restoring your flooded home, see the "Storm Recovery Guide" or "Cleaning Your Flood Damage Home" publications that are available through LSU AgCenter offices or at www.lsuagcenter.com.

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Contact: Claudette Reichel at (225) 578-4440 or creichel@agcenter.lsu.edu
Editor: Tom Merrill at (225) 578-2263 or tmerrill@agcenter.lsu.edu

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