Getting Mildew Off Drywall

The drywall in your home can become infested with mold as a result of flood damage, rain leakage from a poorly insulated roof or high indoor humidity. If you have a large area of mold or mildew due to water damage of any kind, you must replace the drywall. Drywall is highly porous, and mold can hide in and behind the wall. If you just have a small amount of surface mildew — early-stage mold — due to high relative humidity in the home, you can remove the fungus yourself.

Things You'll Need

• Bleach
• Bucket
• Sponge
• Dehumidifier
• Space heater
• Rubber gloves

Instructions

1. Heat your home to dry the wall. You may need to run your central heating unit for several hours to remove the moisture, or you can use a space heater. If the moisture on the drywall results from humidity, you can also use a dehumidifier.

2. Mix a water and bleach solution in a bucket. The Federal Emergency Management Agency (FEMA) recommends 1/4 cup of bleach to a gallon of water for mold remediation, while the Centers of Disease Control and Prevention (CDC) recommend using a full cup of bleach per gallon of water. Do not use any higher concentration than 1 cup of bleach to 1 gallon of water.

3. Put on protective gloves. Dip a sponge in the diluted bleach solution and begin dabbing the drywall wherever mildew appears. Do not scrub the drywall, as this may push more unnecessary moisture into the porous material — and excess moisture caused your problem in the first place. Apply just enough of the solution to coat the mildewed surface with bleach.

4. Dab the drywall with a second damp sponge, this time using only water. This allows you to rinse the wall without soaking it. Do this no sooner than 15 minutes after your initial bleach application, so that the bleach has time to kill the fungus.

5. Dry the wall again. Towels and cloths will prove useless against porous material such as drywall, so you will need to use heat again. If mold or mildew returns in the following hours or days, replace the drywall. Recurrence likely indicates that a mold colony exists deep inside the drywall, or even behind the wallboard.

References

• Centers for Disease Control and Prevention: Facts About Stachybotrys Chartarum and Other Molds
• University of Missouri Extension; How to Prevent and Remove Mildew -- Home Methods; Wanda Eubank, et al.; April 1998
• Federal Emergency Management Agency: Dealing With Mold and Mildew in Your Flood-Damaged Home