Mold on walls may be superficial or a sign of a serious issue. Drawing from expert advice and homeowner experience, I’ll explain proven methods for how to identify and get rid of mold on your walls.
I’ll share my colleague Amanda’s firsthand experience discovering hidden mold and what she did about it. I also spoke with Richard Reid of Universal Restoration of North Florida in Jacksonville, who shared valuable insights about how to identify and handle mold problems in your home.
How to Spot Mold Growth
First, confirm you’re actually dealing with mold. “The main signs of mold in a home include a musty smell, visible discoloration or stains, water damage, recent moisture issues, and allergy-like symptoms,” explains Reid.
He also points out some less obvious indicators that homeowners often overlook, like “high humidity in the home [and] discolored edges of whatever it’s behind.”
Here are the key things to check for:
- Obvious growth: Black, green, or brown spots on walls with a powdery or slimy texture that start small and grow larger.
- Funky smells: A musty, earthy odor, like wet cardboard, gets stronger near affected areas.
- Wall troubles: Peeling wallpaper, bubbling paint, or warped surfaces.
- Water damage: Water stains, discoloration, or constantly damp spots on walls.
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What You’ll Need
Gather your supplies before starting to make the job easier. Here’s what you’ll need to remove mold from your walls safely and effectively.
Safety Gear
Mold spores can cause respiratory problems and irritate your eyes and skin. Take precautions to keep yourself safe.
- N-95 or respirator mask: Filters out mold spores and protects your lungs during cleanup.
- Non-porous gloves: Thick rubber or nitrile gloves extending past wrists.
- Eye protection: Safety goggles to protect from cleaning solutions and spores.
- Protective clothing: Long-sleeved washable shirts and pants that cover exposed skin.
Cleaning Supplies
- Clean rags or paper towels: Opt for absorbent, lint-free cloths, and heavy-duty paper towels.
- Spray bottle: If using DIY cleaning solutions, use a medium-sized bottle with adjustable spray settings.
- Scrub brush: Medium-stiff bristles (softer or hard may be needed based on the wall type) and a smaller detail brush or old toothbrush.
- Sponges: Both regular cleaning and scrubber types.
- Cleaning solution: Use a commercial mold remover or make your own. Test a hidden patch of wall to ensure the solution won’t damage the surface.
Cleaning Solutions
To remove surface mold from your walls, try the following cleaning solutions
- Commercial solution: Only use EPA-registered mold-removal products.
- Hydrogen peroxide: Put it in a spray bottle undiluted.
- Baking soda mix: 1 tablespoon of baking soda in 1 cup of water, a gentle option.
- Vinegar: Add undiluted vinegar to a spray bottle.
Safety Tip: Cleaning supplies (bleach, hydrogen peroxide, and vinegar) should never be combined, as this can produce harmful fumes.
Steps to Remove Mold on Walls
Follow these steps to remove surface mold from your walls safely and effectively. Take your time and complete each step to ensure the best results.
1. Ventilate the Room
Before starting any mold removal work, seal off the room with plastic sheeting and tape, and cover air vents to prevent mold spores from spreading through the HVAC system. Open windows and place a fan in one window facing outward to create good airflow that directs mold particles outside. Good airflow keeps you safe and helps the room dry out.
2. Put on Safety Gear
Put on all your safety equipment before you begin cleaning. This includes your mask, gloves, goggles, and protective clothing. Ensure everything fits properly and is secure to keep you fully protected throughout the process.
3. Apply Cleaning Solution
Work in small sections to ensure thorough coverage. Apply your chosen cleaning solution generously to the moldy areas using a spray bottle or sponge. Start at the top and work your way down to prevent drips and streaks.
4. Allow the Solution to Sit
Let the cleaning solution sit on the moldy surface. Time will vary depending on the solution you use. This waiting period allows the solution to penetrate and break down the mold effectively. Keep the surface damp during this time. If it starts to dry, spray on more solution.
- Commercial mold remover: Follow the manufacturer’s directions on how long you need to wait.
- Bleach solution: Leave on for 10 to 30 minutes.
- Vinegar-based: Leave on the surface for at least 1 hour.
- Hydrogen peroxide: Wait until the hydrogen peroxide stops bubbling, which should take around 10 minutes.
- Baking soda: Wait about 10 minutes.
5. Scrub the Surface
Using your scrub brush, work in circular motions to clean the moldy areas gently but firmly. Pay special attention to corners and crevices where mold tends to accumulate.
- For textured surfaces, use a soft-bristled brush to get into all the grooves without damaging the wall.
- For concrete walls, use a wire brush
6. Clean the Area
After scrubbing, wipe down all surfaces with clean, damp cloths to remove loosened mold and cleaning solution residue. Change your cleaning cloths frequently to avoid spreading mold spores to clean areas. Use fresh water for rinsing to ensure all cleaning products are completely removed from the wall surface.
7. Dry the Surface
Use clean towels or a fan to thoroughly dry the wall surface. This step is crucial and takes an average of 24 hours, as any remaining moisture could lead to new mold growth. Use a moisture meter to verify the wall is completely dry to ensure the job is complete.
8. Final Inspection
Once the surface is completely dry, carefully inspect the cleaned areas for any remaining mold spots, discoloration, or dampness. Run your hand over the surface to check for any remaining moisture or unusual textures. If you spot any issues, repeat the cleaning process on those specific areas before moving on.
Pro Tip: After finishing, dispose of all cleaning materials properly and wash your clothes immediately.
Check out the video below to see the process in action:
See Related: How to Get Rid of Mold in Your Bathroom
Different Walls Need Different Care
Here are the specific methods needed for each wall surface to remove mold effectively without damaging the surface.
- Painted walls: Use gentle pressure to avoid damage. Existing soft spots may indicate that the drywall needs to be replaced. Any drywall that has been affected by mold should be replaced, not cleaned.
- Bathroom tiles: These durable surfaces tolerate stronger cleaners. Pay special attention to grout lines, which easily trap mold.
- Concrete/stone walls: You’ll need to get the cleaner deep into all the porous areas and use a wire brush for tough spots.
- Wallpapered surfaces: It’s recommended that you remove moldy wallpaper, as mold often grows behind it as well.
- Wood paneling: Mold can compromise both the surface appearance and structural integrity of wood paneling. Test affected areas by pressing with a screwdriver — if the wood feels firm, clean it with your chosen cleaning solution. Scrub gently and dry thoroughly.
If the wood has been wet for longer than 48 hours, feels soft, or shows substantial mold growth, replace the affected panels to ensure safety and prevent further damage.
Pro Tip: Moisture breeds mold, so ensure you know what has caused the mold on your wall before trying to clean it. If the source of the moisture (water leaks behind the wall, high humidity, etc.) isn’t corrected, the mold will return.
Personal Experience: Unexpected Signs of Mold
My coworker Amanda S. shared her experience tackling a hidden mold problem, offering valuable insights about water damage detection:
“I discovered mold in my basement bathroom through an unexpected sign — ants! They were eating through the baseboard, following a water leak from an improperly installed sliding glass door above. When I opened the wall, I found spongy drywall and mold covering the plumbing, wall studs, and insulation. It had even spread between the concrete floor and linoleum.
After properly sealing the door, I took a systematic approach: removing damaged materials (drywall, insulation, flooring), thoroughly drying, cleaning with bleach, and installing new materials with Kilz paint applied even on the inside of the wall. My experience taught me an important lesson: Pay attention to unusual signs in your home, as even something like ants could mean you have hidden mold.”
Prevent Mold on Walls
Whether you’ve had a water leak in your home or want to reduce everyday moisture buildup, here are helpful tips to keep the moldy menace from showing up in the first place.
“The areas most susceptible to mold are any places where the humidity is elevated,” Reid notes. “This could be your garage, laundry room, or anywhere a water intrusion can occur (windows, doors, broken pipes, etc.).”
Here’s how to prevent mold growth in your home:
- Control humidity: Keep indoor humidity below 50% to prevent mold growth. Keep your air conditioner running in the warmer months and use dehumidifiers when needed.
- Ventilate properly: Use exhaust fans in bathrooms and kitchens to remove moisture.
- Fix water issues: Immediately repair any leaks in your roof, pipes, windows, and walls.
- Dry water-damaged materials quickly: Thoroughly dry any water-damaged materials and quickly dry or replace any soaked carpets and upholstery. This is key in preventing mold, as mold colonies can start to form within 24-48 hours after a surface becomes wet.
- Upgrade materials: Add mold inhibitors to paint and use mold-resistant shower curtains and cleaning products.
- Clean regularly: Clean bathrooms with mold-killing products and keep surfaces dry.
See Related: How to Prevent Mold in Your Bathroom
When to Call in the Pros
Often you can clean up mold yourself, but there are times when you need to call a professional. Here are some cases when you should get expert help:
- Mold covers more than 10 square feet: Large patches of mold need specialized equipment and expertise to get it all.
- You have underlying health conditions: Those with respiratory issues, weakened immune systems, or allergies should avoid contact with mold.
- Mold keeps returning: Recurring mold can indicate a hidden moisture source, an HVAC infestation, or a structural issue that needs to be addressed by a professional.
The Bottom Line on Mold
If you find mold on your walls or anywhere else in your home, it’s important to act quickly, but always ensure your safety first. Wear protective gear and use cleaning solutions designed to fight mold. To stop mold from coming back, keep your home well-ventilated and fix moisture issues right away. These simple steps will help keep your walls fungi-free.
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Main Image Credit: Svetlana Golovco / Adobe Stock Free / License
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