How to Clean Mold Off Walls

Tips to remove it permanently and when to call a pro

By
Mary Marlowe Leverette
Mary Marlowe Leverette 2018
Mary Marlowe Leverette

Mary Marlowe Leverette is one of the industry's most highly-regarded housekeeping and fabric care experts, sharing her knowledge on efficient housekeeping, laundry, and textile conservation. She is also a Master Gardener with over 40+ years of experience and 20+ years of writing experience. Mary is also a member of The Spruce Gardening and Plant Care Review Board.

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Updated on 02/19/24
Reviewed by
Katie Berry
Katie Berry
Reviewed by Katie Berry
Katie Berry is a cleaning expert with 30 years of household management experience and 12 years of writing about cleaning methods and routines for Housewife How-Tos. She is the author of several books about homemaking.
Learn more about The Spruce's Review Board
Closeup of someone scrubbing mold off of a wall

The Spruce / Almar Creative

In This Article
Project Overview
  • Working Time: 30 mins - 8 hrs
  • Total Time: 1 hr - 1 day
  • Skill Level: Beginner
  • Estimated Cost: $0 to $5

Small colonies of mold, even toxic molds, can be removed with some basic disinfecting supplies you probably have on hand by following safety procedures. However, if the mold growth is extensive, it is a good idea for a professional mold removal company to test and remove the mold. The U.S. Department of Environmental Protection recommends professional removal of mold colonies that cover more than 10 square feet (roughly a three-foot by three-foot patch). Local public health departments offer advice on mold testing and refer you to a mold remediation company.

Mold spores are all around us, and all it takes for them to activate is some moisture and warmth. Mold growth can happen anywhere the conditions are optimal on any surface from wood to tile to sheetrock walls. The mold you discover on your walls can be black, green, brown, or white. If the colony is large, it is important to determine which type of mold growth you have before tackling the cleaning job to determine the overall health effects to your and your family.

How to Know If You Have a Mold Problem

Mold should be removed as quickly as possible once it is discovered. You may not always see mold, but these signs are indicators that there may be a mold problem in your home:

  • You detect a musty smell in your home. The odor signals a mold problem that needs to be addressed.
  • You have neglected a leaky faucet or roof.
  • A wall that feels soft or damp to the touch may indicate that there is interior mold growth that will soon appear on the surface.
  • There is moisture accumulation that takes a long time to evaporate from walls due to poor ventilation in the house.

What You'll Need

Equipment / Tools

  • Protective gloves
  • Protective eyewear
  • Protective facemask
  • Step ladder
  • Plastic bucket
  • Sponge
  • Microfiber cloth
  • Measuring cups
  • Spray bottle
  • Soft-bristled brush

Materials

  • Chlorine bleach
  • Dishwashing liquid
  • Hydrogen peroxide
  • Distilled white vinegar

Instructions

Tools needed to clean mold off of walls

The Spruce / Almar Creative

  1. Mix the Mold Cleaning Solution

    In a plastic bucket, mix one-part dishwashing liquid, 10 parts bleach, and 20 parts water. To clean a small area of mold, mix a solution of one tablespoon dishwashing liquid, 1/2 cup chlorine bleach, and one cup of warm water in a spray bottle. The dishwashing liquid helps the solution cling to the wall longer to kill the mold spores.

    Warning

    When working with bleach, use caution to avoid the inhalation of dangerous fumes. Bleach should never be combined with any product that contains ammonia or vinegar.

    Adding chlorine bleach to a mold cleaning solution

    The Spruce / Almar Creative

  2. Protect Yourself

    When removing mold, it is best to wear old clothes that you don't mind being splattered with bleach and that can be washed in hot water to remove any mold spores that might scatter to the surface. Put on a face mask (N-95 is recommended), protective eyewear, and gloves.

    Protective gear for cleaning up mold

    The Spruce / Almar Creative

  3. Increase the Ventilation in the Room

    To improve ventilation while you are cleaning, open windows or add a circulating fan. If you are working in a bathroom, turn on the bathroom ventilation fan and use the exhaust fan in the kitchen.

    Opening windows to increase ventilation

    The Spruce / Almar Creative

  4. Apply the Cleaning Solution

    The cleaning solution can be applied with a spray bottle or a sponge. It's best to clean mold starting at the bottom and working your way up. This keeps the spores from spreading and the stain from streaking on your wall. The surface of the wall should be fully wet but not oversaturated to prevent damage to the drywall. If the mold is near the ceiling, always use a sturdy stepladder or apply the solution with a clean sponge mop.

    Spraying cleaning solution onto the moldy area

    The Spruce / Almar Creative

  5. Air-Dry the Wall

    Do not wipe away the cleaning solution. Allow the wall to air-dry.

    Allowing the wall to air dry

    The Spruce / Almar Creative

  6. Check for Remaining Stains

    Once the wall is completely dry, check the area for any dark stains. If they remain, repeat the steps with a fresh chlorine bleach cleaning solution.

    Reapplying the bleach spray if mold remains

    The Spruce / Almar Creative

Alternative Ways to Remove Mold

Chlorine bleach is the most effective home-removal product for killing mold spores. However, if the infestation is small, you can use distilled white vinegar or hydrogen peroxide to kill the spores.

Distilled white vinegar is acidic enough to slowly break down the structure of the mold and kill it. However, dark stains may remain and require additional scrubbing with a household cleaner. Spray the mold with 100 percent distilled white vinegar, wipe away the mold with a microfiber cloth or sponge, and allow the area to air-dry.

Hydrogen peroxide will kill mold and lighten stains but it works more slowly than chlorine bleach and may require multiple applications. Spray the mold with three-percent hydrogen peroxide (first-aid grade), wipe the area with a sponge, and allow the wall to air-dry.

Tips to Prevent Mold Growth on Walls

  • Repair leaky plumbing and roofs promptly.
  • Improve air circulation in the home and reduce moisture with a dehumidifier.
  • Install a moisture barrier in unfinished basements and crawl spaces.
  • Clean mold and mildew-prone rooms weekly (bathrooms, laundry rooms, kitchens).
The 3 Best At-Home Mold Tests of 2024, But Consult a Professional First
FAQ
  • When is it best to call a professional regarding mold?

    It is best to call a mold professional if the mold covers a large surface area, you are unable to identify what type of mold it is, or if the mold is in a tricky-to-reach area like a crawlspace.

  • How do you identify toxic mold?

    Toxic mold has a very distinct smell, like decay or rot, so that will usually be your first indicator. It also will appear more slimy or furry than other types of mold. It is generally green-ish or gray-ish black.

  • When should you use mold deterring paint?

    You can opt to use mold-resistant paint in areas with high humidity or condensation, such as bathrooms. It's best to use only if you've seen signs of mold or mildew already, but doesn't need to be used otherwise.

  • How can I get more information on mold in my home?

    To get more information on mold in your home, you can consult your local health department or reach out to a mold professional.