How to Remove Mold from Walls for Good

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.