Four Steps to Preventing Mold Growth after a Flood

The Healthy House Institute (HHI) is pleased to share these steps for preventing mold growth after a flood.

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Aside from stopping the source of the moisture, it’s important to promptly remove wet furnishings and porous materials from the flooded area to enable a thorough damage-assessment, and drying and restoring contents that have not been compromised.

Some of it - such as wet/moldy carpet, drywall, upholstery and fabrics - will need to be discarded.

Vacuum using HEPA-wet-dry vacuums to remove moisture, mold and soils without spreading allergenic or unhealthy mold and dust particles around your home. According to the IICRC, "It is preferable to use a HEPA vacuum, but a simple wet/dry vacuum can work. When using a wet/dry vacuum, attach a hose to the exhaust and vent the exhaust air to the outside. This keeps dust, spores and other fine particles from being suspended in the air and settling back on clean surfaces."  Sponsored Link - Professional Wet-Dry Vacuums and HEPA Wet-Dry Vacuums.

In the case of minor “clean” flooding, say from a small burst indoor water pipe, homeowners can remove smaller wet items themselves, but should wear goggles, gloves, long sleeves and an N-95 respirator to avoid exposure to mold spores that may already be present in the environment.

Clean mold from smooth surfaces using a weak bleach-water solution (1/4 - 1/2 cup bleach per gallon of water). Use gloves, eye and skin protection and plenty of ventilation. If you are sensitive to mold or chemicals, have someone else do it.

If the flooding is excessive and/or “dirty” - e.g., from a rising river or sewer backup - expert help is needed to protect health and property.
 

Step Two – Dry It Out and Quickly

Mold spores are everywhere, but need moisture to “germinate” – so drying affected areas is Step Two. Since mold can grow within 24 to 48 hours, quick action is critical.

Aside from obviously wet areas, experts using special meters can check for and locate moisture - even finding hidden wet/moldy places, such as inside wall cavities - and implement techniques to enable a thorough drying-out process. They may also use special fans or “air-scrubbing” equipment with HEPA filters. See also Step Three.

Step Three – Air It Out

The flooded, wet area will need fresh air and ventilation to dry it out, but take care not to spread mold spores around your home by improper “airing”. Consult with an IICRC-certified firm to set up “containment”– a fancy word that means keeping doors closed, putting up plastic sheeting, exhausting air to the outdoors, and other measures to enable the drying and ventilation process without exposing loved ones to contaminated air from the flooded area.

Step Four – Keep it Dry to Keep It Out

The cardinal rule for preventing mold growth is – Keep it Dry. Strive to ensure your home’s insides are staying dry.  It’s also a way to protect the investment of your home, since excess mold growth and moisture will damage the structure, in addition to being unhealthful.

Try to keep indoor humidity below 50% using air conditioning or a dehumidifier. Have carpets cleaned by professionals that use equipment to clean and properly dry your carpet.

Keep mold outside where it belongs.

Tip: Use a water-sensing alarm (battery-operated) in moisture-prone areas such as next to the washer, the hot water heater, in the basement and other possible wet zones, so you are alerted if excess moisture happens.

Tip: If you can’t use a HEPA vacuum to clean, damp-wipe surfaces to remove mold. Put moldy items in plastic (bags or sheets) before you take them out.

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