Cleaning up after a flood

Health concerns for cleaning up after a flood

Information provided by LSU AgCenter:

Prevent further damage to your flooded home and your health

A flood-damaged home requires special attention to avoid further damage and health hazards from molds, other fungi, algae, and bacteria. Wetness and high humidity spur their growth within two to three days, so it's essential to act fast after a flood, according to Claudette Reichel, LSU AgCenter extension housing specialist.

Mold and other fungi are bad for the house and for the occupants. Mold spores are an allergen and some types of molds produce mycotoxins. Decay-causing fungi grow in wood that stays wet for an extended period, causing it to lose strength.

"In a nutshell, a wet house is soon an unhealthy house and eventually a rotting house. To make matters even worse, such secondary damage may be excluded from coverage on your flood and homeowner's insurance," Reichel said.

If your home has been flooded, it should be cleaned and dried quickly and thoroughly to prevent mold and future damage by wood rot. Because flood water may be contaminated with sewage or other biological pollutants, it's advisable to safely disinfect, too. Areas wetted by clean rainwater—for instance from a leaking roof—may not need to be disinfected. All wet areas should be allowed to dry thoroughly before being covered or enclosed.

"A professional water damage restoration contractor with special drying equipment is the best and safest way to go" Reichel said. "But after a flood many homeowners don't have that option."

For safety, wear protective clothing on legs, arms, feet, and hands while cleaning up debris. Wear rubber gloves and goggles while handling flood-damaged items.

Buildings constructed before 1978 may have lead-based paint. Sanding or scraping this paint creates a serious health hazard. Visit for more information about lead-based paint before disturbing it. If you hire a contractor to do any work that could disturb paint, be sure the contractor is certified by EPA as a Lead Certified Renovator, Reichel said.

Disinfectants should be chosen and used carefully because they can pose a hazard, too. Commercial disinfecting cleaners need to be diluted as directed to be effective. Bleach solutions, such as 1/4 cup to 1/2 cup liquid chlorine laundry bleach to a gallon of water, are economical general purpose disinfectants but can damage finishes, colors and metals and pose hazards to people. Never use chlorine bleach in or near the air conditioning system. Never mix bleach with products containing ammonia or acids; that can produce toxic fumes, Reichel said.

Begin by removing wet carpets, carpet pads, and rugs within 24 hours. Disinfect the slab. You may be able to clean valuable carpets and rugs but always replace carpet pads, Reichel said.

Remove vinyl, laminate, and other impermeable flooring over wood subfloors immediately after the flood has receded. Clean the subfloor. Drying may take weeks in Louisiana's humid climate—less if you can dehumidify the space.

"A buckled subfloor may flatten out on drying, so be patient," Reichel said.

For wood floors, carefully remove a board every few feet to reduce buckling. Leave open until the flooring is dry.

Check inside exterior walls for wet insulation.

"Remove all wet insulation, even if it means cutting into wallboard," Reichel said.

Flush out the insides of the walls. Allow and help wetted areas to dry thoroughly before installing new insulation.If possible, air condition and use a dehumidifier to speed the drying of materials by drying the indoor air.

Fiberglass, cellulose and other porous insulation should be replaced with new material. Saturated insulation will hold water, even if the wall looks dry, and eventually cause wood rot and mold problems. Using insulating foam-board (extruded polystyrene) cut to fit or closed-cell spray foam filling up to 60 percent of the wall cavity can eliminate the need to replace insulation in the next flood.

Check the attic; remove all wet insulation. Let everything dry before replacing the insulation.

Open closet and cabinet doors. Remove drawers for drying and to let air circulate. With slow drying, these may be salvageable, depending on the materials.

Paneled walls have potential to be saved by prying the paneling loose at the bottom. Remove any wet insulation; wash the wall cavity. Hold the bottom of the paneling away from the sill until everything is dry.

Remove vinyl wallpaper to allow sheetrock or paneling to dry. Removing baseboards will help too. Refinish interior walls with latex paint - never use vinyl wallpaper - to allow the walls to continue to dry to the inside. A shellac-based sealer, however, may be needed over ceiling water stains before painting.

Consider replacing all material removed with flood-hardy materials that could withstand future flooding and need only cleaning, instead of replacement. Choose ceramic tile, solid vinyl tile or solid wood flooring (with a vapor permeable finish) and elevate equipment, when feasible. If your flooded walls have solid wood studs and plywood or board sheathing, consider insulating with closed-cell foam spray insulation or rigid foam boards to fill 60 percent of the wall cavity, and finish with paperless drywall leaving gaps behind molding. After the next flood, you could then remove moldings, flush out the wall cavity and avoid having to gut and replace all the materials.

For more disaster recovery information, visit and select Family and Home, then Hazards and Threats. Or try

A detailed how-to guide, Rebuild Healthy Homes: Guide to Post-disaster Restoration for a Safe and Healthy Homes is published by the U.S. Department of Housing and Urban Development and available online or as a mobile app.

See and learn more about hazard-resistant and high-performance housing at and by visiting LaHouse Resource Center in Baton Rouge.

Take these steps for mold removal and prevention after a flood

To prevent mold growth in your home after the flood water recedes takes a meticulous approach. Mold colonies can start to grow within two to three days, so getting things clean and dry as fast as possible is critical, according to Claudette Reichel, LSU AgCenter extension housing specialist.

Take these steps first:

  • Remove wet carpeting and pads right away, as well as wet draperies and upholstery.
  • Cut into wallboard and remove all wet and damp insulation, 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.
  • If your home was built before 1978, it could contain lead-based paint and asbestos materials. Disturbing such materials can create dangerous health hazards. Before you do that, learn more at and, wear protective gear and use safe work practices.
  • Clean with nonphosphate detergents because any phosphate residue is mold food.
  • If you disinfect, follow directions carefully and never mix bleach with ammonia or acids such as vinegar or lemon juice. Disinfectants can kill molds but do not prevent new growth on damp materials.
  • 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 reliable moisture meter before replacing insulation. Before you close the wall, wood should drop at least below 20 percent moisture content to prevent decay and preferably below 16 percent to prevent mold growth.
  • Do not use vinyl wallpaper. That would prevent further drying to the inside.

To clean up mold, follow these guidelines. More detailed information is at

  • Minimize your exposure during clean-up. People are exposed to mold mainly by breathing spores or fragments, but can also be exposed through skin contact. Wearing gloves and a respirator that can filter mold spores (N-95 or better) is recommended.
  • Isolate the 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 the 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. This includes 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 should be removed and replaced.
  • Clean surface mold on nonporous materials such as hard plastic, concrete, glass, metal and solid wood. 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, but it is not a substitute for cleaning. In the case of sewage contamination (including floodwater), disinfection is recommended. On color-fast, 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.

  • Consider borate treating wood. While walls and subfloors are exposed is a great time to treat them with a penetrating borate solution to provide safe protection from termites and decay. The coating may also help to deter mold growth during the drying time.
  • 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 look dry can still be wet enough to support regrowth.
  • 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 should be removed. Rebuilding should wait until all affected materials have dried completely.
  • You can reduce future damage by restoring your home with flood-resistant materials and elevating equipment where possible. Consider ceramic or solid vinyl tile flooring and wall assemblies that can be washed and dried with solid wood studs, plywood (no OSB), closed-cell foam insulation, and paperless drywall with latex paint or removable wainscoting.

See and learn more about hazard resistant housing at and by visiting LaHouse Home and Landscape Resource Center in Baton Rouge. Find more storm recovery publications at, including Mold Removal Guidelines for Your Flooded Home. For a detailed "how-to" guide, see HUD's Rebuild Healthy Homes: Guide to Post-disaster Restoration for a Safe and Healthy Home, a free online publication and mobile app from HUD.

FEMA offers the following additional tips for dealing with hazardous waste after a flood:

Hazardous waste should always be separated from non-hazardous materials. Types of hazardous waste includes:

  • Cleaning products such as bleach, ammonia, and polishes
  • Pesticides and repellants
  • Automotive fluids
  • Paints, varnishes, and solvents
  • Batteries, fluorescent lightbulbs, and items containing mercury
  • Fire starters, accelerants, and other flammable items

Materials contaminated with flammable products should be separated from all other waste and stored in a well-ventilated area. If stored outdoors, flammable materials should be placed in a covered, fire-resistant container to prevent soil or groundwater contamination.

In the case of a chemical or oil spill, survivors are encouraged to call local authorities before contacting the Louisiana Department of Environmental Quality (DEQ) at 1-888-763-5424.

Specific instructions for all waste removal, including hazardous waste removal, are available at the DEQ website at

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