Cleaning mold quickly and properly after a flooding event

By Connie Neal, Housing & Environmental Design Specialist

If your home or business was affected by the recent flooding, there are many issues that you will be dealing with.  One of them may be mold.  Cleaning mold quickly and properly is essential for a healthy home, especially for people who suffer from allergies and asthma, according to the Federal Emergency Management Agency (FEMA).

Mold and mildew can start growing within 24-48 hours after a flood, and can lurk throughout a home, from the attic to the basement and crawl spaces.  The best defense is to clean, dry or, as a last resort, discard moldy items.

Even though it can be hard to make decisions to discard favorite items or something of sentimental value, in an effort to safeguard the well-being of your loved ones, a top-to-bottom home cleanup is your best defense.

Many materials are prone to developing mold if they remain damp or wet for too long. FEMA recommends beginning a post-flood cleanup by sorting all items exposed to floodwaters:

  • Wood and upholstered furniture, and other porous materials can trap mold and may need to be discarded.
  • Carpeting presents a problem because drying it does not remove mold spores.  Carpets with mold and mildew should be removed and discarded.
  • Glass, plastic and metal objects and other items made of hardened or nonporous materials can often be cleaned, disinfected and reused.

All surfaces exposed to flood waters should be cleaned, disinfected and dried as soon as possible.  To ensure a safe and effective cleanup, good ventilation is important as well as wearing the proper protection when cleaning.  Open windows for ventilation and wear rubber gloves and eye protection.  Consider using a mask rated N-95 or higher if heavy concentrations of mold are present.  Use a non-ammonia soap or detergent to clean all areas and washable items that came in contact with floodwaters.  The National Environmental Health Association and the National Center for Healthy Housing recommends using ½ cup to no more than 1 cup of bleach per one gallon of water to disinfect the area.  Then, thoroughly rinse.  Allow to dry thoroughly.  Never mix bleach with ammonia as the fumes are toxic.  Cleaned areas can take several days to dry thoroughly.  Using fans, and dehumidifiers will help speed up the drying process.

Check out all odors.  It is possible for mold to hide in walls and behind wall coverings.  It is important to find all mold sources and clean them properly.  Remove and discard all materials that can’t be cleaned, such as wallboard, fiberglass and cellulose areas.  Then clean the wall studs where wallboard has been removed and allow the area to dry thoroughly before replacing the wallboard.  According to Michael Goldschmidt, State Housing & Environmental Design Specialist, University of Missouri Extension, the moisture content of the wood members should be 13-15% or less before going back with new wallboard.  To measure the moisture content of walls, use a moisture meter which measures the moisture inside the material, not just the surrounding air.  Contact your local University of Missouri Extension center for further information as to their policy regarding the use of this resource.

Flood-dampened surfaces carry other risks besides mold as floodwaters may contain sewage and biological contaminants that can linger after the initial cleanup.  It is important to keep children, sick family members and pets out of the flood-affected area until cleanup can be completed.  Make sure that you are up to date with your immunizations, especially tetanus.

The University of Missouri Extension website has a free guide, MP904, Resources for Your Flooded Home available for download at http://extension.missouri.edu/p/MP904.  It offers information about electrical systems, repairing walls, cleaning furniture, flooring and floor coverings, bedding, kitchen items and controlling mold and mildew.  There is also information on financial advice, filing insurance claims, avoiding fraud and hiring a contractor.  For other tips about post-flooding cleanup, visit www.fema.gov, www.epa.gov, or www.cdc.gov.

 

Cleaning up after a flood

By Connie Neal, Housing & Environmental Design Specialist

Many homes and businesses have been affected by the recent flooding.  There are many issues surrounding flooding and recovery which can be a somewhat slow process.  It is important to be cautious before and during the cleanup process.   Because floodwaters may contain sewage and biological contaminants that can linger after the initial cleanup, there are some precautions you can take to protect yourself and your family.   It is important to keep children, sick family members and pets out of the flood-affected area until cleanup can be completed.  Make sure that you are up to date with your immunizations, especially tetanus.

Because of what you are dealing with, it is imperative that you have the proper protection.  You should wear rubber boots, rubber gloves and goggles during cleanup.  Wear a mask with an N-95 or P-100 label.  Even better, but more expensive is a half-face piece respirator with removable cartridges.  People who have asthma, allergies or other breathing conditions may be more sensitive to mold exposure and can exacerbate the problem.  If your health is compromised in any way, this is not a safe environment for you.

Upholstered furniture, mattresses or pillows that have been submerged are pretty much impossible to salvage.  If the piece seems worth the effort to save, see pages 5, 16 and 17 of the MU Extension publication listed at the end of this article.  Mattresses can be sent to a commercial renovation company for cleaning and disinfecting, however, it may be less costly to purchase new.  Items such as stuffed animals, baby toys, pillows, foam-rubber items, cosmetics, wall coverings, books and most paper products should be removed and discarded.

The Federal Emergency Management Agency (FEMA) recommends the following procedures be followed when pumping a basement to avoid serious damage, collapse or injury:

  • Begin pumping when floodwaters are no longer covering the ground outside.
  • Pump out one foot of water.  Mark the water level and wait overnight.
  • Check the water level the next day.  If the level went back up (covered your mark) it is still too early to drain your basement.
  • Wait 24 hours and then pump the water down one foot again.  Check the level the next day.
  • When the water in the basement stops returning to your mark, pump out two or three feet and wait overnight.
  • Repeat daily until all water is out of the basement.

According To Michael Goldschmidt, State Housing & Environmental Design Specialist, University of Missouri Extension, water will mitigate mostly through drywall, wood framing and insulation.  It will soak up fastest in insulation so you should plan on removing drywall and all insulation up to the next floor level at a minimum.  When the water is out of the basement, you will need dehumidifiers and fans to get the moisture to 13-15% on the wood studs assuming there are wood studs in the basement.  To measure the moisture content of walls, use a moisture meter which measures the moisture inside the material, not just the surrounding air.  You may borrow a moisture meter from most local University of Missouri Extension centers.    If the basement wall is all concrete, and no exterior/interior wood studs at that level (like in a walk-out basement), you should remove any drywall and insulation that may be in the floor joists above, but the next floor above should be okay if you dehumidify and blow fans in the house right away.  The indoor humidity levels should be measured constantly and kept below 50%.

Thoroughly clean all hard surfaces with hot water and laundry or dish detergent.  Allow to dry thoroughly before disinfecting.  You can speed up the drying process by using fans and dehumidifiers.  After the initial cleaning and drying, it will be important to disinfect these items and surfaces using ½ cup but no more than 1 cup of bleach per one gallon of water.  Never mix bleach with other cleaning solutions.  After disinfecting, the surfaces should be thoroughly dried again.

Wash clothes that were contaminated with flood or sewage water in hot water and detergent.  After completing cleanup, wash your hands with soap and warm water.  If you become ill at any time during cleanup, seek immediate medical attention.

The University of Missouri Extension website has a free guide, MP904, Resources for Your Flooded Home, available for download at http://extension.missouri.edu/p/MP904. It offers information about electrical systems, repairing walls, cleaning furniture, flooring and floor coverings, bedding, kitchen items and controlling mold and mildew.  There is also information on financial advice, filing insurance claims, avoiding fraud and hiring a contractor.