Rip it Up and Start Again: Mold Removal Clean-Up Best Practices

Although a flood can be a devastating event within our homes and throughout the built environment, the risk of mold growth in the aftermath of a flood can be equally as destructive if the proper actions are not taken.

USG recommends the following best practices for mold removal in the wake of a flood:

Act Fast to Stop Mold

Mold spores begin to germinate within 48 hours of the initial wetting, so it is imperative to stop mold growth at the source.

After a flood, you can stop the progression of mold growth by drying out the building as fast as possible. This includes opening and draining all cavities, such as inside walls, doors, closets, and cabinets. Using dehumidifiers and fans can help circulate air and draw out moisture to help quicken the drying process and stop mold germination in its tracks. If drywall or plaster has been saturated by contaminated floodwater, it should be removed.

The importance of the first 48 hours is crucial in the clean-up of mold. The risk of mold growth increases substantially after 48 hours. Although the most obvious mold growth can be seen or smelled, mold thrives under or behind objects like carpet, cushions, or walls.

The actual removal of molded items can be dangerous and, ideally, you would seek the help of qualified professionals. In situations where you must handle mold, you should always wear personal protective equipment, such as:

• Respirator mask (at least N95)
• Non-latex nitrile or rubber gloves
• Eye goggles without holes or vents
• Rubber boots
• Disposable clothing, including long sleeves and pants

Remember that mold is not the only danger that you must prepare yourself against, as floodwaters can contain raw sewage or industrial overflow filled with bacteria or toxic materials.

Clean-Up Can Get Messy

Only after you have finished drying out the building can you then begin to assess the water damage. If the damage is too severe and beyond repair, the only option to salvaging the space is to completely tear-down and replace it with a new system.

In the case of more moderate damage, the existing drywall must be removed to be at least 2 feet above the line where floodwater was in direct contact with the walls. Buildings built before 1980 will require extra caution, as their materials may contain asbestos or lead-based paint. If you are ever in doubt, consult a professional before continuing with the repair.

Removing any porous materials that have been flooded from the building, such as carpeting or insulation, can drastically reduce the conditions that promote mold growth. Any materials that cannot be thoroughly dried and cleaned should be thrown out.

At this point, if you do not have to do a complete tear-down of the affected space, clean any hard, moldy surfaces with water and detergent. Never mix products containing bleach or ammonia and make sure that you do not contribute to any additional mold growth by drying any surfaces as soon as they’re clean.

The Aftermath

After completing the clean-up of the flood, conduct a full inspection of the building to ensure that mold growth does not continue. Remember, it’s just as important to use your nose as it is to use your eyes when completing this inspection. Following these steps will help ensure that mold will not risk the health of everyone involved, from yourself to other building occupants.

Additional information from USG on mold maintenance and eradication can be found here; an accompanying video on mold removal and clean-up best practices can be found here.

FEMA also provides comprehensive resources related to mold & mildew removal in addition to guides on flood recovery and building materials that are resistant to flood damage: Dealing with Mold & Mildew in Your Flood Damaged Home, Initial Restoration for Flooded Buildings, and Flood Damage-Resistant Materials Requirements.