How to Remove Mold from Walls for Good

Clean

Get rid of mold on your walls with these easy homemade sprays then keep it from coming back for good.

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 higher humidity areas, 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 your 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 prone to mold. 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 Get Rid of Mold on Your Walls

These steps remove mold from painted or unpainted walls, drywall, cement, and ceilings using homemade mold-killing sprays. 

 Equipment You’ll Need

  • Protective clothing
  • Old towel
  • Spray bottle
  • Cleaning rags
  • Scrub brush or scouring pad
  • Plastic sheeting (for larger areas)
  • Painter’s tape or masking tape (for larger areas)

Materials You’ll Need

  • Borax powder (20 Mule is one brand)
  • Distilled white vinegar
  • Chlorine bleach
  • Water

Wear Protective Clothing

Mold can cause severe respiratory symptoms and skin irritation. Wear a filtered mask to avoid breathing in mold spores. To prevent skin reactions or cross-contamination, wear rubber gloves, a long-sleeved shirt, and pants that you can launder in hot water, which will kill any spores they pick up. (Plan on immediately washing or discarding all of them as soon as you’re done.)

Prepare the Area

First, clear the area of decorative items, curtains, and other objects. If you can’t remove something — like heavy furniture — cover it with plastic sheeting and use painter’s tape to secure the plastic. Then, protect the floor where you’ll be working by taping a piece of plastic to the floor and covering it with an old towel to catch drips.

Finally, since mold spores can travel easily in the air, protect the rest of your home by shutting the door to the room where you’ll be working. If that’s not possible, or if the room is a large one, hang plastic sheeting to block off the area.

Removing Mold from Wallpaper

Use this method for finished, painted, or wallpapered surfaces. For unfinished surfaces, skip to the steps below to remove mold from drywall. Create a natural mold remover spray by combining 2 tablespoons of borax*, 2 ounces of distilled white vinegar, and 16 ounces of hot water.

Spray the area well, then immediately scrub it with a clean cloth or brush to remove the surface layer of mold. Then lightly respray the area, using only enough to dampen the spot — you don’t want it dripping. Wait 10 minutes and wipe it with a clean, fresh cloth. Let it dry overnight without rinsing — the remaining acetic acid from the vinegar will work overnight to finish killing mold you can’t see.

Removing Mold from Tile, Stone, Concrete, and Cement

For hard surfaces, combine 2 ounces of chlorine bleach and 16 ounces of cool water in a spray bottle. Spray the area until saturated but not dripping, then scrub it with a rag, scouring pad, or brush and wipe away the residue. Lightly respray the area, wait 15 minutes, and then wipe the area with a fresh cloth dampened with water. Let the area dry overnight and inspect it the next day. Repeat if needed.

Removing Mold from Drywall or Ceilings

Drywall and ceiling materials are porous, so the mold you see on the surface most likely has threaded its way below the surface, too. Combining 1/4 cup bleach in 2 cups cold water makes an easy homemade stubborn mold killer. Spray the surface until damp but not dripping and let the area air-dry.

Then, respray it, wipe away any residue with a fresh cloth, and reapply a final light round of spray. Let this dry overnight, and the spray will continue killing mold as it dries. (For popcorn or textured ceilings, do not rub the area — just let the spray air dry.)

Covering the Mold Stain

Killing the mold does not always remove the discoloration. If the mold leaves a light stain, you’ll need to apply an oil-based primer (like Kilz 2), then use your preferred paint to cover the area once the primer is completely dry. Don’t skip the primer — the mold stain will show through paint without it.

Tips to Keep Mold from Growing

Since mold prefers a dark, humid environment, opening your windows daily to circulate fresh air is an easy way to discourage mold growth. If someone in your family has allergies, do this very early in the morning or late in the afternoon — times when pollen counts are at their lowest. If opening your windows isn’t possible, at least open your curtains during daylight hours.

In Basements

Condensation on your basement windows or walls will cause mold growth. If you find condensation, you need better insulation. Add weatherstripping around doors, caulk gaps around windows, and insulate walls if needed.

Consider adding exhaust fans to basement bathrooms or laundry areas. These spots tend to have high humidity that leads to mold growth. If you can’t add an exhaust fan, run a floor or stand fan at least once a day to circulate dry air.

Switch to hard flooring. Although a carpet feels warmer underfoot in a basement, it also collects and traps moisture, leading to mold. Replacing carpet with a good barrier underlayment and hard flooring will help prevent mold in your basement. And you can always use throw rugs to keep your feet warm.

Swap faux plants for real ones. Live plants help clean your home’s air, but their damp soil invites mold to grow in a stuffy basement. Silk or plastic plants don’t cause mold problems, especially if you keep your fake plants clean.

Use a hygrometer to measure humidity and a dehumidifier to keep it in check. An inexpensive hygrometer lets you continually monitor the moisture levels in your basement, so you can keep them at an ideal 60% by running a dehumidifier. Make sure to empty the dehumidifier and clean its reservoir regularly, though, or it will just become another source of mold in your basement.

In Bathrooms

Use your bathroom’s exhaust fan. Run it while you’re showering and for 15 minutes after every shower or bath to keep the room’s humidity levels in check. In homes without exhaust fans, use a stand-alone fan to circulate air. For safety, opt for a battery-operated fan that you can clip to a towel rack or shelf.

Squeegee or wipe the shower walls and door after every shower to reduce moisture. Or skip the squeegee and use this homemade daily shower cleaner spray that prevents mold and mildew. Then leave your shower doors open so that air can circulate. For shower curtains, shake them to dislodge water, then leave a gap to either side so air can circulate.

Regularly inspect places prone to leaks. Watch for moisture at the base of toilets and beneath your sinks, and immediately fix any leaks you find.

In the Rest of Your Home

Inspect your interior hoses. You should replace flexible hoses on washing machines and kitchen sink sprayers immediately if you see a leak or condensation, and every five years, even if you don’t spot problems. If you don’t replace them on time, your homeowner’s or renter’s insurance won’t pay if they burst and cause water damage.

Inspect your roof after storms. Look for loose shingles or other damage that could allow water to enter your attic or home.

Keep your foundation clear. Don’t stack firewood or other items against your home’s foundation, or you’ll encourage water collection there that will seep into your basement walls.

Fix cracks promptly. Whether you find cracks in your foundation or siding, fix them immediately to keep water out of your home.

Clean your gutters in the Spring and Fall. Clogged gutters lead to water pooling near your foundation or along your walls, and that leads to water damage that causes mold.

Remember, mold won’t go away on its own. If you find signs of it growing on your walls, you need to take prompt action to get rid of it with these easy homemade mold-killing sprays. Then keep it from coming back by controlling your home’s humidity levels, promoting good air circulation, and regularly cleaning to remove mold spores.

35 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. 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.

  9. 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.

  10. 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!

  11. 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!

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Rosemary Davis says:

    Hi,

    We are redecorating our hallway. Hacking out some of the cracks to refill we noticed green and blue spots on the exposed areas which were underneath the emulsion. We can treat the areas shown but assume that the uncovered parts are the same. Have you any suggestions as to what we should do.

    Many thanks
    Rosemary

    1. Katie Berry says:

      Hi Rosemary,
      I’d suggest painting the entire hallway with a mold-blocking primer before applying new emulsion. Killz or Zinsser are two brands that work well. Be sure to look for the mold-blocking version, since it will prevent any green or blue spots from discoloring your new paint.

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