If you have extensive damage and mold growth, the best practice is to hire a reputable firm that is licensed and trained in dealing with water damage and mold remediation. But that may be difficult after a disaster. You may have to do the clean-up yourself. If so, follow the steps below:
1. Wear protective gear
People are exposed to mold by breathing spores and by skin contact. Wear gloves, goggles and a NIOSH-approved respirator rated N95 or higher. Some respirators have valves to make it easier to breathe. A properly fitted half-face N100 respirator with filter cartridges provides greater protection and comfort than the mask types.
2. Take an inventory
Compile a room-by-room inventory of missing or damaged goods, and include manufacturers’ names, dates and places of purchase, and prices. Take photographs to document the damages for insurance purposes.
3. Isolate and Ventilate
Disturbing mold colonies during clean-up can cause a huge release of spores into the air, so seal off the moldy areas from the rest of the house. Open windows, and don’t run the central heating or air conditioning system during clean-up. Tape plastic over air grilles, and drape plastic in stairwells if other levels are dry and clean. If you have power, put a box fan in a window to blow out and exhaust mold-filled air to the outdoors.
4. Remove moldy porous materials
Porous moldy or sewage-contaminated materials should be removed, put in plastic bags and discarded. To reduce the release and spread of mold spores, it is helpful to cover moldy material with plastic sheeting before disturbing it.
Specific removal considerations:
Remove all flooded carpeting, upholstery, fabrics and mattresses right away. It’s best to discard them, but if you hope to salvage a valuable rug or furniture, have it professionally cleaned, disinfected and dried. Tell the cleaner about the mold and its cause. Never reuse flooded padding.
Remove all wet fibrous and open cell foam insulation – even if wallboard appears to be dry. Wet insulation will stay wet far too long, leading to the growth of hidden mold and wood decay inside the walls. Cut wall covering above the level that was wet; water can wick up above the flood level.
It’s best to remove all moldy, porous materials (except solid wood), especially if there is heavy or long-term mold growth, such as paper-faced drywall and flooring, processed wood products, ceiling tiles and paper products.
Plaster and non-paper faced drywall walls that have dried, are in good condition and have no insulation in the wall may be cleaned and sanitized to salvage them. However, there is a risk of mold on the backside that can release spores into the indoor air. If you choose to restore these materials, try to seal all interior gaps to be airtight before repainting.
Remove all vinyl wallpaper and any other materials that hamper drying. Interior-side vapor barriers or foil-faced insulation should be removed.
5. Clean and disinfect
Surface mold can be cleaned from non-porous materials such as china, hard plastic, glass and metal; solid wood can also be cleaned since mold grows only on its surface. Cleaning should remove mold, not just kill it, because dead spores can still cause health problems.
Clean items with non-phosphate detergents (any phosphate residue is mold food). When disinfecting, follow the directions carefully and never mix bleach with ammonia or acids (vinegar). Disinfectants can kill molds, but they do not prevent regrowth. The CDC’s recommendations for cleaning mold growth off hard surfaces are 1 cup (240 mL) bleach to 1 gallon (3.8 L) water. Mix 1 cup (240 mL) of bleach in 1 gallon of water. Wash surfaces with the bleach mixture. If surfaces are rough, scrub them with a stiff brush. Rinse surfaces with clean water. Allow to air dry.
Consider borate treatment. Applying a borate treatment to wood framing provides resistance to termites and decay, and may inhibit mold growth. The type that penetrates the wood over time offers greatest protection. Do NOT apply sealants that can hamper drying.
6. Speed dry
After you have removed moldy, porous materials and cleaned and disinfected, it’s important to do all you can to dry wet materials as quickly as possible. Close windows and if possible run the air conditioning or heat, run fans, and use a dehumidifier. (Contractors who specialize in water damage restoration have special equipment [dehumidifying blowers] that dry materials faster than other methods.) If there is no power, keep windows open. Pay special attention that subfloors, slabs and wall framing are completely dry before replacing insulation, wallboard and flooring.
7. Remain on mold alert.
Continue looking for signs of dampness and new mold growth. Mold can form in as little as 2-3 days if materials stay damp. Wood and other materials that may look dry can still be wet enough to support new growth. If mold returns, repeat cleaning and use speed drying equipment and moisture meters. Regrowth may signal that the materials aren’t dry enough or should be removed.
8. Do not restore until all materials have dried completely.
Get a moisture meter to test the moisture content of studs and sheathing before replacing insulation. Wood products specialists recommend that wood have no more than 14-15% moisture by weight before you close the wall.
9. Restore with flood-resistant materials. If possible, restore with materials that can withstand a flood with less damage. Use closed-cell foam insulation that does not absorb water and solid wood or water-resistant structural materials. Elevate wiring and equipment. Consider removable wainscoting or paperless drywall, and water-tolerant flooring such as ceramic tile, solid wood, stained concrete, etc. Some new wallboard materials may be more mold-resistant. Do NOT use vinyl wallpaper, oil-based paint or other finishes that block further drying on the inside.
Centers for Disease COntrol and Prevention. Cleaning and Sanitizing with Bleach after an Emergency, https://www.cdc.gov/disasters/bleach.html.
Harris, Janie. Texas A&M AgriLife Extension Service. Controlling mold growth after the storm. Publication ER-010, 8-06, https://texashelp.tamu.edu/wp-content/uploads/2016/02/ER010-controlling-mold-growth-post-storm.pdf.
Reichel, Claudette. Louisianna State University Extension Ag Center. Mold removal guidelines for your flooded home. LSU AgCenter publication 2949-B, 02/17, http://www.lsuagcenter.com/NR/rdonlyres/CABFF19A-1781-4C7E-B58C-1588F203A588/29666/Pub2949BMoldRemovalFINAL1.pdf
U.S. Department of Housing and Urban Development, Office of Lead Hazard Control and Healthy Homes. Rebuild Healthy Homes: Guide to Post-disaster Restoration for a Safe and Healthy Home https://portal.hud.gov/hudportal/documents/huddoc?id=Rebuild_Healthy_Home.pdf. May 2015.