How To Prevent Mold After Your House Floods

Where there's water, mold soon follows. Mold causes major damage to our homes and health, so prevent it from taking hold with these steps.

No matter how well-built, our homes can’t always stand up to the destructive power of water. Water carves riverbeds through rock and washes entire communities away in floods. It can also bring another unrelenting force into our homes: mold.

Molds exist everywhere, often beneficially, in the environment. But unchecked, mold growth in our homes destroys building materials and can cause health problems like asthma, particularly in the immunocompromised.

“Mold can grow in as little as 24 to 48 hours given a food and moisture source,” says Michael Rubino, author of The Mold Medic, an Expert’s Guide on Mold Removal and founder of HomeCleanse and Change the Air Foundation. That’s why it’s important to act fast, if you can do so safely, to prevent mold from establishing after a flooding in the house.

How To Prevent Mold After Flooding

“Properly addressing and drying out a space after a water-related event” will help prevent mold growth, says Rubino. Molds thrive in damp places with lots of organic material, and flooded homes fit the bill.

Once molds find a suitable place to reproduce, they’ll grow and not stop until you stop them. Here’s how to prevent mold from taking root in your home:

Safety first

Don’t enter a flooded home until it’s safe. For a major flood event, like a hurricane, this might mean waiting for the authorities to allow entrance. Wear long pants and sleeves, rubber boots and gloves. And, bring a change of clothes. Mold spores cling to fabrics and can easily be transferred to your next destination.

Turn off the electricity if you can safely do so. Never touch your electrical panel if it means you’ll be standing in water to reach it, though. Call a licensed electrician before proceeding with any cleanup.

Generators used in the cleanup process must be placed outside and away from the home to avoid carbon monoxide exposure.

Dry it out

“It’s best to stay away from fans while trying to dry out a space,” Rubino says. Fans introduce and blow around mold spores and bacteria, which makes cleanup harder. Fans also won’t address the humidity, which needs to be below 60 percent to inhibit mold growth.

Rubino recommends using dehumidifiers instead of fans — just make sure it’s the appropriate size for your space. You may need more than one.

The Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA) say it’s okay to use fans before mold growth starts, but direct the airflow outside to avoid blowing contaminants into other areas of your home.

Document everything

This is a good time to start taking pictures of your home and belongings. Document the damage to your home and personal property for your insurance company, and for your own edification — floods are stressful, and you don’t want to forget what you threw away.

Make decisions

“Choosing what to keep and what to throw away depends on how successfully the surfaces can be decontaminated,” says Rubino. Porous items like clothing, lampshades and carpet should just be thrown away. Contamination that gets down into the fibers of these items is very difficult to eradicate.

Semi-porous items like leather and unsealed wood should probably be tossed, especially if you have standing water, says Rubino. Even though these items look smooth, molds send out roots, called hyphae, deep within the fibers below.

Non-porous surfaces like metal, glass, sealed countertops and finished wood can be safely cleaned and disinfected.

Remove all wet materials

Physically remove all mud, debris and water-logged items. Use a wet-dry vacuum to clean as much water out of the remaining structure. Remove drywall to a foot above the water line, and cut out all wet insulation. Cut carpeting and pads into sections, roll them up and place them in garbage bags.

Clean and sanitize

Wash and dry all remaining surfaces with soap and hot water, then follow with a sanitizing solution. The CDC recommends one cup of household chlorine bleach — the bottle should list a concentration between five percent and nine percent — to five gallons water for surfaces not already contaminated by mold. Allow to air dry.

Where To Check for Mold After a Flood

Mold spores are tiny, and it’s impossible to see where they land and grow until you have a problem on your hands. In addition to carpeting, insulation and building materials, here are some surprising hiding places:

  • Particleboard furniture. The surface may look cleanable, but the porous inside is a prime spot for mold.
  • Toilet tanks. Rubino recommends checking toilet tanks once per month even in the absence of a flood, so clean them after a water event, too.
  • Appliances. Hidden areas of fridges and other appliances can harbor molds. Clean out your fridge’s drip pan and in and under your washing machine.
  • HVAC vents and intakes. Make sure to have HVAC units inspected before turning them on.

How To Kill Mold After a Flood

If it’s been 24 to 48 hours since the flood, assume you have mold. Rubino recommends hiring a certified mold inspector before attempting remediation. Visible mold growth often isn’t the best indicator of a lurking mold issue.

If you decide to tackle the cleanup yourself, know your limits: “Anything larger than 10 square feet should automatically be handled by professionals,” says Rubino. That’s not a very big space — a little over three feet wide by three feet long.

Wear an N95 (or better) mask or respirator. Wear rubber gloves and goggles to protect your hands and eyes. Follow the steps above to clean and dry your home, and toss out moldy items and building materials.

Scrub hard surfaces with hot soapy water to remove visible mold. The CDC says to follow with a mixture of one cup household chlorine bleach to one gallon of water, rinse and allow to dry. Read all labels and never mix household cleaners like bleach and ammonia.

Molds and other contaminants can cause long-term health and structural damage, so don’t risk trying to DIY if the job is too big. Mold remediation companies have the expertise and equipment to get the job done right. For sentimental items like family photos, restoration companies specializing in mold removal may be able to help.

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Ally Childress
Ally Childress is a licensed electrician and freelance writer living in Dallas, Texas.