How to Remove Mold from Painted Walls

As a rule of thumb, small patches of mold growing on painted walls and surfaces at home can usually be safely removed by cleaning with a diluted bleach solution and thoroughly drying the affected area.

However, it also depends on the type of material your wall is made of and how far the mold contamination has spread. Here’s what to know about removing mold from painted walls.

Can Mold Grow On Painted Walls?

Yes — mold can grow on painted walls and surfaces if there is excess moisture.

Most types of paint contain organic compounds that can be metabolized by mold, such as plasticizers. Oil paints are especially susceptible to mold because they contain more of these organic compounds compared to water-based paints.

Cleaning and Removing Mold

If you’re dealing with a small area of mold, you may choose to remove it yourself instead of hiring a professional. In general, cleaning with a bleach and water solution is sufficient to deal with minor mold problems at home.

However, in some situations DIY mold removal isn’t advisable and will likely allow the mold to regrow or spread:

• There is significant mold growth covering more than 10 square feet.
• You suspect there’s mold hidden inside, beneath, or behind visible surfaces.
• The underlying moisture issue that allowed mold to grow has not been identified or addressed.

Keep in mind that porous materials with visible fungal growth (e.g. rotted wood, wallpaper, carpet, insulation) cannot be cleaned and should instead be removed and discarded.

Walls that are fully painted or sealed can be treated like non-porous materials, even if the underlying substrate is wood or drywall. According to the Institute of Inspection, Cleaning, and Restoration Certification (IICRC):

“Mold growth in a surface of condensation on painted walls or non-porous surfaces can usually be removed by vacuuming, washing with dilute biocide and detergent, cleaning, thoroughly drying, and repainting.”

How to Remove Mold from Painted Walls

What you’ll need: rubber gloves, N-95 mask, goggles, household bleach, water, 2 large buckets, 2 sponges or disposable rags, spray bottle (recommended), towel or dehumidifier (recommended), HEPA vacuum (recommended)

Preparation

1. First, make sure that the underlying source of moisture (e.g. leaks, condensation, water damage) has been properly corrected and the area has been thoroughly dried.
2. Wear personal protective equipment (gloves, mask, and goggles) and open windows to make sure the work area is well-ventilated.
3. Remove and double-bag unsalvageable mold-contaminated materials (e.g. carpets, wallpaper, insulation) in 6-mil or thicker polyethylene bags before discarding them. Large items and upholstered furniture should be covered with plastic sheeting and sealed with duct tape.

Mold Removal (From Painted Walls)

1. Fill one of the buckets with soap and water.
2. In the other large bucket, prepare a diluted bleach solution by mixing 1 gallon of warm water with 1 cup of bleach. Diluting the bleach this way will help kill mold without causing damage or discoloration to painted walls. Never use undiluted bleach or mix bleach with ammonia.
3. With a spray bottle or sponge, lightly dampen the moldy areas with soap and water. This prevents spores from becoming airborne.
4. Soak a sponge or rag in the diluted bleach solution and thoroughly scrub the entire affected area until mold colonies are no longer visible. Make sure that all sections of painted walls with or near mold have been wiped down with the bleach solution.
5. Wait at least 10 to 15 minutes to allow the bleach solution to soak in and kill the remaining mold.
6. Soak a clean sponge or rag in soap and water, then wipe down the area to remove the bleach residue. Do not use the same sponge or rag that you used earlier to apply the bleach. Rinse the sponge in the bucket as needed until the entire wall has been cleaned.
7. Dry the entire area by wiping it with a towel or using a dehumidifier to remove as much water and moisture as possible.
8. After the area has been thoroughly dried, use a HEPA vacuum to clean up any remaining dust and mold debris. When you’re done, empty the contents of the vacuum into sealed plastic bags.

Can You Paint Over Mold?

It might be tempting to spray the mold with a disinfectant and simply paint over it. DO NOT DO THIS.

Paint applied over moldy surfaces is likely to peel, and unless it is properly cleaned and removed, mold might still be growing between the wall and the paint. Adding new paint only acts as a temporary cover-up.

According to the EPA: “the issue with paint is that it traps moisture between the paint and the wall, further aiding and abetting the growth of the mold.”

If you see mold growing on painted walls, follow the steps above to clean and remove it before repainting.

About Green Orchard Group

Green Orchard Group is a leading provider of environmental health and safety services in New York City. Our licensed mold assessment and remediation professionals are here to help you with any type of mold question or problem.