How to Remove Mold from Walls

Clean

Once you’ve seen the first signs of discoloration, you need to figure out how to remove mold from walls fast to keep it from spreading and causing both health and structural issues. Follow these tips and use the mold removal spray recipes below to get your mold situation under control.

Inspecting for Wall Mold

Just about every home develops mold at some point. Surprisingly, newer homes get it more often than older ones.

That’s because mold occurs in areas of higher humidity, and the tighter seals around windows and doors in new home construction keep in more moisture than drafty old homes.

Signs of Mold Growth

The most obvious sign of a mold problem is finding green, brown, orange or even black spots. But there are other, less apparent signs:

  • Cracked or peeling paint
  • Discoloration
  • A recurrent “soot” or black streaks, specks, or dots
  • Bulging
  • A musty, damp smell

Where You’ll Find It Growing

Mold on basement or exterior walls occurs when water vapor in the air meets a cold surface and turns the vapor into a liquid.

Bathrooms and laundry rooms develop mold because they’re typically very humid.

Other humid areas include the walls and ceiling near humidifiers and any room with a hot tub or jacuzzi improperly installed indoors.

Mold also grows where there is (or has been) a water leak. Places like the cupboards under sinks are very prone to it. Once a pipe has leaked, there’s a good chance mold will grow unnoticed within the wall until the problem requires expert removal.

How to Remove Mold from Walls in Your Home

How to Remove Mold on Walls

Steps to remove mold from painted or unpainted walls, drywall, cement, and ceilings using homemade mold killing sprays.
Print
Total Time8 hrs 30 mins

Equipment

  • Protective clothing
  • Old towel
  • Spray bottle
  • Cleaning rags
  • Scrub Brush
  • Plastic sheeting (for larger areas)
  • Painter's tape or masking tape (for larger areas)

Materials

Natural Mold Remover

  • 2 tablespoons Borax
  • 1/4 cup white vinegar
  • 2 cups hot water

Stubborn Mold Remover

  • 1/4 cup chlorine bleach
  • 2 cups cold water

Instructions

  • Wear Protective Clothing. Mold can cause severe respiratory symptoms and skin irritation.
    Wear a face covering, so you don't breathe in mold spores while you remove them.
    Wear rubber gloves to protect your hands from contact with mold spores.
    Wear a long-sleeved shirt and pants that can be laundered in hot water to kill any spores they pick up.
    Woman wearing face mask, long sleeves, and rubber gloves as she removes mold on window and wall
  • Prepare the Area. Mold spores easily travel in your home's air. Close the door to the room where you'll be working, or use tape to hang plastic sheeting to block off the area.
    Remove all decorative objects, curtains, and other items from the area where you'll be working. If you can't remove something like heavy furniture, cover it with plastic sheeting. Tape the plastic down, so it stays in place.
    Place an old towel on the floor where you'll be working to catch any drips. If the area is carpeted, tape a piece of plastic sheeting in place to prevent stains.
  • Removing Mold from Paint or Wallpaper. Use this method for finished, painted or wallpapered surfaces. For unfinished surfaces, skip to the steps below to remove mold from drywall.
    Use the Natural Mold Remover Spray recipe. Spray the area well then immediately scrub with a clean cloth or brush to remove the surface layer of mold.
    Reapply the spray, lightly this time. Use only enough to dampen the area — you don't want it to drip. Wait 10 minutes, then wipe with a clean, fresh cloth. Do not rinse. Let the area dry overnight.
    Hand in rubber glove pointing spray bottle of homemade mold remover at mold growth on painted wall
  • Removing Mold from Tile, Stone, Concrete, and Cement. Wait at least 24 hours after using the Natural Mold Remover Spray to apply the Stubborn Mold Remover Spray. They are not safe to combine.
    Open the windows to ensure adequate ventilation. Use the Stubborn Mold Removal Spray recipe. Apply the spray and immediately scrub the area with a clean rag or scrub brush. Then, lightly reapply the spray and wait 15 minutes.
    Wipe the area with a clean cloth dampened with water. Let the area dry overnight.
  • Removing Mold from Drywall or Popcorn Ceilings. These surfaces are porous, which means the mold grows on the surface but may also thread its way into the structure of the drywall/ceiling material.
    Use the Stubborn Mold Remover Spray recipe. Spray the surface until it's damp but not dripping. Wait a few minutes for the drywall to absorb the spray then apply more. Wait 15 minutes.
    Get a clean cloth damp with the Stubborn Mold Removal Spray and scrub the area. Do not let the cloth come into contact with other surfaces, or you may spread the mold spores.
    Wipe the area with a clean cloth dampened with more Stubborn Mold Removal spray. Do not rinse. Let the area dry overnight. Do not use a fan to dry it — the spray will continue killing mold as it dries.
    If the any discoloration remains, apply an oil-based primer (like Kilz 2) to seal the stain. Use your preferred paint to cover the area once the primer is completely dry.

How to Stop Mold from Growing on Walls

To get rid of mold on walls permanently, remove it using the steps above. Then, adopt the following practices to keep it from returning.

In Basements

  • Open curtains daily. Sunlight is a natural mold killer.
  • If your basement has windows and doors, open them a few minutes each day to allow air to circulate.
  • Use fans or space heaters to circulate air in basements without windows.

In Bathrooms

  • Use bathroom fans after every shower or bath for at least 10 minutes.
  • Use a mold-prevention spray or squeegee after every shower. (Related: Homemade Daily Shower Spray.)
  • Keep shower doors open to allow air to circulate. Plastic shower curtains should be shaken well to dislodge water droplets then left partially open.
  • Replace damaged caulk or grout in your shower and tub immediately.
  • Clean your bathrooms, kitchen, and laundry room weekly. Look for signs of moisture or leaks in cabinets.

In the Rest of Your Home

  • Keep your home’s humidity levels in check. Overly humid air contributes to mold and mildew growth.
  • Visually check your roof after severe storms for loose shingles or other damage that could allow water to enter your attic or home.
  • Keep debris and junk away from your home’s foundation so water does not collect there and seep into your basement or under your home.
  • Watch for signs of cracks in your foundation and contact foundation repair specialists immediately if you see any.
  • Inspect your washing machine hose quarterly and replace it every five years even if it does not show wear. (Many homeowner insurance policies will deny claims for water damage if you don’t!)

45 Comments

  1. Delores Lyon says:

    Thanks for sharing these different recipes! I just noticed that the corner space between the walls and ceiling of my bathroom are an odd color. The last thing I want is mold damaging my home, so I am going to spend my Saturday getting rid of it. Hopefully these homemade cleaners will do the trick!

  2. And thanks for the recipe, hopefully it does the trick.

  3. Some great info here, a lot of people just don’t realise that condensation is one of the main causes of mould on walls. Prevention is a must, bleach and water help when cleaning but proper ventilation is key when it comes to battling mould issues. Really good article with some helpful tips. Thanks for sharing.

  4. We had a leak in a room and now there is a white coating on a wood armoire- is that mold?

  5. Wilma Schoenheit says:

    I have mold in a closet next to the air conditioner filter. I’m wondering if it come from the attic and somethings leaking from Ac!

    1. Katie Berry says:

      It could be something from above, or moisture building up inside the closet. You should probably schedule an AC tuneup to have it inspected.

    2. I live in a RV and the clothing closet always has mold and if you lean something against that wall then it gets mold on it. It happens every year. How to stop it.

    3. dehumidifier

  6. Donna might want to try putting damp rid in the closet. I hang it in my closets.

    1. Katie Berry says:

      Damp Rid is wonderful. A box of sidewalk chalk works, too!

  7. I have mold on wood stained doors. Do your 2 methods work for them too?

    1. Katie Berry says:

      Yes, but (there’s always a “but”, right?) don’t leave the solution in contact with the wood for too long or it might lighten the wood. It’s better to lightly reapply it several times than risk having a discolored spot from a heavy-handed application. 🙂

  8. Rusty Mitchell says:

    I have water saturated baseboards in my bedroom about 6 inches up. I am getting an itchy throat but I know I’m not sick so it must be from mold.
    I’m burning two essential oil diffusers to mitigate the bad air and I keep window open with two fans on high all day. Is there anything else I can do to keep my bedroom temporarily habitatble? My landlord is waiting for an appraisal to send in a mold clean out crew.

    Thanks

    1. Katie Berry says:

      Diffusers won’t mitigate mold spores in the air. Running your fan and keeping the windows open (assuming it’s not raining or terribly humid outside) will help. You might want to tape/tack tarp over the saturated areas to keep the mold spores contained. That won’t help dry it out, though, which might upset your landlord so you’ll have to choose between your health and his/her happiness.

  9. stephanie says:

    Thank for the advise of removing mould of the wall. I live in the UK and not sure what to use instead of Borax or where I can buy it.

    Any help in purchasing Borax, would be very helpful

    thank you

    1. Katie Berry says:

      Hello, Stephanie! Unfortunately, Borax is not available for sale in the UK due to different health and safety regulations but you can find substitutes (which are sodium borate, sodium tetraborate, or disodium tetraborate) that work almost as well, though. Look for “Borax Substitute” at Tesco in the cleaning aisle — both “Dripak” and “Clear and Natural” brands work equally well. They’re also available on Amazon. Here’s a link to the UK listing.

  10. On My bedroom walls (near the window) and bathroom walls ..I’ve noticed moulds growing ..and it has also affected our skin ..we cleaned it then it came again …we are extremely upset with this problem…pls suggest good solutions..
    Thanks

    1. Katie Berry says:

      First, try cleaning using the instructions here. Then, be sure you’ve caulked properly around your bathroom windows and that you are running your bathroom fan for 15 minutes every time someone finishes bathing. If you continue to have problems, call a professional.

  11. Katie Berry says:

    Excellent tip. Thanks!

  12. In our RV we have a mould problem on the ceiling of the bathroom mostly in the winter when it is stored… I have tried to keep the vent open and closed.(no difference ) we use Driz.air to absorb moisture. Is the moisture coming from the toilet or/and bath drain? If I use the cleaning methods you suggest could I then paint the ceiling with special paint?

    1. Katie Berry says:

      Once you’ve killed the mold you should use a primer designed to fight mold. I don’t know whether there’s a specific one for RVs but I’m sure an RV place could tell you.

  13. I live in an apt here in Mexico. The structure here is made of cinder blocks & cement. I notice black stuff is growing on the walls. Even more I’ve been cooking beans in the Crickpot for just a few months (July-January) usually with the windows open but this winter has been cold so the last few months ive cooked with all the windows shut closed. I notice all my walls including the bathroom are soaked. Now with minimal black creeping in various places does this mean that ALL my walls & ceilings need to be washed down. If so Im gonna need some help!

    1. Katie Berry says:

      It could be mold or just plain mildew but, without seeing it, I really don’t know. Either way, it’ll keep spreading unless you clean it. Sorry!

  14. I have mold that keeps forming in my single bedroom I share with my partner. The room is always cold my dad doesn’t use the heating . I’ve noticed when we wake in the morning they is water running down the walls. Ended up with mold forming round the corners/edges and window. I’ve wiped them and dried them also got a small dehumidifier but not resolved the situation… help?

    1. Katie Berry says:

      Without heat, the temperature difference between the water (in pipes, the toilet tank, etc.) and the ambient air will cause condensation.

  15. Going to go for bleach had a pipe leak and it got the walls in a closet damp 4 inches high now its green almost 3 ft high. Can’t leave the door a open my cat will go in but I can put a fan and space heater in there space heater will shut off automatically after 15 minutes come back on in a half hr. I will pull the plug if I leave the house

    1. Katie Berry says:

      If it’s that bad, I think you’re smart to go straight to the bleach solution. Good luck!

  16. Claudia B. says:

    We used the natural mold removal spray (Borax, vinegar, water) on mold on painted walls inside a closet, using your instructions. It did a pretty good job, but most areas still have gray mold residue and a couple of areas still show black mold. What do you recommend? If the bleach method, how much time should go by before using it.

    1. Katie Berry says:

      Hi Claudia,
      You should wait at least 24 hours, or until the walls are completely dry, whichever is later. The reason for waiting is to ensure the vinegar from the first solution is dry and inactive, since mixing bleach and vinegar creates chlorine gas.

  17. the tip about replacing the hoses on the washing machine also applies to the flex hoses on flick mixer sink taps too they have a tag with a manufacture date on them they also have a replacement date if your hoses haven’t been checked regularly by a plumber and replaced by the due date no insurance for burst pipes. they are the most common cause of water damage in kitchen and bathroom cabinetry.

    1. Katie Berry says:

      Great point. Thank you!

  18. I have a cinderblock building that we have insulated and finished the walls with Sheetrock. Every year we have a powdery green mildew, I presumed, form on the walls during winter and early spring. We do not have heat or air in the building and only use it during summer trade. What can we do to prevent this from occurring and best way to remove and treat.

    1. Katie Berry says:

      Hi Junell,
      The only real way to stop that mildew from forming is with adequate air circulation. Without it, any moisture in the air will collect on the walls and cause mildew and possibly mold, too.

  19. Do you use hot water in both recipes, or.just.the one for stubborn stains? Thanks!

    1. Katie Berry says:

      Hi Kay,
      Hot water is for the first mold killer recipe only. I’ve updated the stubborn mold killer recipe to indicate that it needs cold water. That’s because hot water makes the active ingredients in chlorine bleach ineffective, and also increases the risk you’ll inhale harmful fumes. Hope that helps!

    2. Thank you so much Katie, I appreciate your help. I’m glad I asked because I would of used hot water in both.

    3. Katie Berry says:

      I’m happy to have helped, Kay, and apologize I wasn’t more clear the first time.

  20. I have a home on stilts near the bay. Only in the last 6 months has what appears to be mold began to grow in our very tiny hallway off the bathroom. Is this from moisture from the bathroom? Why now?

    1. Katie Berry says:

      It’s hard to answer “why now.” It could be a variety of things, like a warmer season this year or less wind circulating the air, which would let mold and mildew grow.

  21. Katrina wardrop says:

    Hi I’m desperate I’m 77 just lost my hubby. I live in England. And everything seems to be falling apart around my home , I’m pretty good at coping but the biggest problem is my utility room my washing machine, dryier fridge freezer, and boiler is in there.I’m south facing so the sun gets in there all through spring and summer but once November till March my wall wall statute covering in black dust which I can wipe I’d but behind washing machine etc, the walls are black I open my window as soon as I get up and shut it around 6pm. I had something fitted to my window which you can open and shut I leave this open all the time.my hubby would deal with this as I can’t bend through osteoarthritis but he’s not here and I’m afraid to trust anyone in the house and I have money for professionals please please can you advise. Thank you katrina

    1. Katie Berry says:

      Hello Katrina,
      First, let me extend my condolences on your loss. It is a horrible thing to have happened, and I know how overwhelming it can be trying to figure things out and move forward.

      With respect to your utility room, your second comment (not posted) indicated that you didn’t want to hire professionals. So, the suggestions which follow are ideas you can try on your own.

      It sounds as if you’ve got plenty of ventilation in there if you’re opening the utility room window that often. Since that’s the case, I suspect the black dust you’re seeing is carbon exhaust from the boiler. (And the timing of November through March, when one would run the furnace due to the chill) seems to support that.

      So, I’d recommend looking up your boiler’s operating manual online and find out how to replace the filter. A clogged filter would cause the exhaust to vent in your utility room, so changing to a fresh one might solve your problem. While you’ve got the manual in front of you, read up on how often the filter needs to be changed and any other maintenance tasks they recommend homeowners do on their own. Also, make sure the boiler isn’t crowded by other things in the utility room, since it needs plenty of space to intake air.

      Best wishes,
      Katie

  22. Arnel Abano says:

    Hello, you mentioned that sunlight helps rid of mold? If I have an area that does not get direct sun, can I use a UV light to replace the sunlight?

    1. Katie Berry says:

      You can certainly try it, especially if it puts out heat since that reduces the moisture which mold needs to thrive.

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