How to Clean Mold Off Walls

Mold growth on walls is a common problem that many homeowners face. If left untreated, mold can cause serious health issues and damage to your home. Thankfully, with the right products and techniques, you can effectively remove mold from your walls and prevent it from coming back.

Understanding Mold on Walls

Before we dive into the cleaning process, it’s important to understand what mold is and why it grows on walls in the first place.

What Is Mold?

Mold is a type of fungal growth that develops in damp, humid environments. The spores land on surfaces and begin feeding on organic materials, spreading outward as they form colonies. Mold can be different colors, like black, green, or white.

On walls, mold feeds on materials like drywall, wood, wallpaper, paint, and insulation. It can cause permanent stains and damage if left for too long.

Why Does Mold Grow on Walls?

Mold spores are present everywhere in the air we breathe. However, they will only begin growing when the right conditions are present. The main factors that cause mold on walls include:

  • Moisture – From leaks, flooding, high humidity, or damp basements. Excess moisture allows mold to thrive.
  • Lack of ventilation – Stagnant air and poor airflow encourage mold growth.
  • Sources of dampness – Leaky roofs, plumbing issues, condensation, etc. Mold will appear where there is persistent moisture.
  • Organic materials – Drywall, wood, paper, etc provide nutrients for mold.

By controlling moisture and air circulation, you can prevent mold from recurring after removing it. Proper ventilation and fixing leaks is key.

Cleaning Mold Off Walls

When you discover mold on your walls, you want to clean it off as soon as possible. Mold spreads quickly when left alone. Here are the basic steps:

Step 1: Protect Yourself

Cleaning mold comes with health risks if you aren’t properly protected. You should wear:

  • An N95 respirator mask
  • Gloves
  • Goggles

Avoid touching mold with bare hands or inhaling spores. Limit your exposure when cleaning. Consider asking a professional if you have allergies or a compromised immune system.

Step 2: Assess the Affected Area

Inspect where the mold is coming from and how far it has spread. Look in surrounding areas for moisture sources. This will help you locate the root of the problem.

Identify any materials like drywall or insulation that may need replacement after cleaning. Porous surfaces can harbor mold spores even after disinfecting.

Step 3: Mix a Mold Killing Solution

For non-porous surfaces, mix an effective anti-mold solution. Bleach mixtures work well:

  • 1 part bleach
  • 1 part water

Or you can use stronger antimicrobial cleaners found at hardware stores. Make sure your product states it kills mold and mildew.

Note: Don’t mix bleach solutions with other cleaners. Never use bleach on metals as it can corrode them.

Step 4: Clean the Moldy Areas

Now you’re ready to start scrubbing away the mold. Work systematically from the outer edges in toward the middle. This helps avoid spreading spores.

Apply your mold killing solution with a brush, sponge, or cloth. Scrub gently but thoroughly until all visible mold, staining, and discoloration is gone.

Rinse cleaned areas with fresh water to remove residues. Be sure to dispose of any sponges or rags used in the garbage.

Allow all surfaces to dry completely before moving on.

Step 5: Allow to Dry

It’s crucial that affected areas dry out fully before continuing. Keep windows open and use fans or dehumidifiers if needed.

Remaining moisture will let new mold regrow quickly. Don’t proceed until all walls and lingering dampness have dried.

Step 6: Treat Porous Surfaces

If you have mold on drywall, insulation, wallpaper or other permeable materials, the spores can hide deep inside. Chemical cleaning won’t reach them all.

In these cases, you often need to:

  • Replace damaged drywall
  • Remove wallpaper
  • Discard old insulation
  • Re-paint with mold resistant paint

This eliminates lingering spores that could recolonize later. Talk to a contractor about the extent of removal needed.

Step 7: Disinfect Again

Once fully dry, do a second application of your anti-mold cleaner. This helps kill any remaining spores. Allow to dry fully.

Repeat disinfecting as needed until mold is completely eradicated. Persistence and thoroughness are key.

Step 8: Fix Moisture Issues

With the mold gone, now you can address what caused it. Hunt down and repair all water leaks or humidity sources.

Improve air circulation and add exhaust fans. Maintain low indoor humidity, ideally between 30-50%.

If the issue is humidity from a damp basement, you may need professional basement waterproofing.

Tips for Preventing Mold

Prevention is the best way to avoid recurring mold problems. Here are some handy tips:

  • Inspect for leaks and dampness regularly. Act quickly when found.
  • Run dehumidifiers to maintain low indoor humidity.
  • Ensure bathrooms and laundry have working vents and fans.
  • Open windows regularly to circulate fresh air.
  • Install vapor barriers in basements and attics.
  • Clean bathroom grout and tile with anti-mold cleaners.
  • Avoid carpet in damp areas. Use tile instead.
  • Make sure downspouts direct rainwater away from your home’s foundation.
  • Clean out gutters and drainage systems so water doesn’t pool.
  • Insulate cold surfaces like pipes to reduce condensation.

Catching and fixing moisture issues promptly goes a long way in preventing mold growth on walls and other surfaces. Proper ventilation and dehumidification will also help a mold-free indoor environment.

When to Call a Professional

In some mold situations, it’s best to call in a mold remediation specialist:

  • If you have a mold allergy or sensitivity
  • For large areas of mold growth
  • If mold is inside walls or HVAC systems
  • If the source of moisture is unknown
  • If mold persists after thorough cleaning
  • For mold testing and identification

Remediation pros have powerful tools, protective equipment, and expertise to fully dry out affected areas and kill mold on a deeper level. They can also address hidden mold behind walls that may require demolition.

For severe cases or mold in inaccessible areas, professional mold remediation may be your best bet.

FAQs About Removing Mold Off Walls

Let’s review some common questions when dealing with mold on walls:

How do I know if it’s mold on my walls?

Look for small black, green, or white spots that grow in colonies. Rub your finger over them – mold feels slightly fuzzy. Damp, dark areas are typical locations. Musky, earthy odors are also a sign of mold.

What is the black mold on walls?

Black mold, also called Stachybotrys chartarum, is a dark greenish-black mold. It grows on very wet materials like drywall or carpet. It can cause a range of health issues so clean it promptly.

Can I paint over mold on walls?

No, paint will only temporarily cover mold. It will continue growing under the paint. Always clean and disinfect walls thoroughly before painting over moldy areas.

What kills mold permanently?

No cleaner will permanently kill mold, as spores are everywhere. Removing moldy materials and fixing moisture issues prevents it from returning. Maintaining a dry, well-ventilated home is key.

Does sunlight kill mold?

Sunlight can slow mold growth, but does not kill or remove it. Physical cleaning and disinfecting are necessary to eliminate mold colonies.

Does vinegar kill mold on walls?

Yes, vinegar is a mild antimicrobial that can kill mold on non-porous walls. Use undiluted white vinegar and allow longer contact time. It may take more scrubbing than stronger cleaners.

How do you get rid of mold on walls naturally?

You can make a natural mold killing solution from vinegar, hydrogen peroxide, baking soda, or tea tree oil. However, commercial mold cleaners are usually more effective.

What is the fastest way to remove mold from walls?

Mixing a strong bleach solution and scrubbing vigorously removes mold quickly. Ensure proper ventilation. Work systematically from the edges in towards the middle.

How long after cleaning mold should I paint?

It’s best to wait at least 2-3 days after mold cleanup before painting. This allows time for surfaces to fully dry so mold doesn’t grow under the new paint.


Mold growth on walls should be addressed promptly to prevent worsening of the problem. With the proper safety gear, mold killing solutions, and cleaning techniques, you can effectively remove mold without professional help in many cases.

Be sure to take steps to prevent mold from recurring after cleaning by fixing underlying moisture issues and maintaining good air circulation. Keeping humidity low will also deter mold growth.

While cleaning small areas of household mold off hard surfaces like bathroom tiles or walls is often doable on your own, don’t hesitate to call a mold remediation specialist for larger infestations or if mold persists after thorough DIY treatment.

Stay vigilant for early signs of mold or excessive moisture, act quickly to treat it, and your home can stay mold-free for good.