Remove Mold from Walls: Expert Tips and DIY Mold-Killer Sprays
Discovering mold growth on your walls can be alarming, because it’s unattractive and poses health risks. In this article, I cover the process to effectively remove mold from walls using two homemade mold-killing sprays made from common household ingredients. Plus, I’ve got some practical strategies that can help you keep mold from returning and ways to keep it from developing in the first place.
Signs of Mold Growth
Mold often appears as green, brown, orange, or even black spots, but there are other less apparent signs to watch out for, including:
- Cracked or peeling paint
- Discoloration
- A recurrent “soot” or black streaks, specks, or dots
- Bulging
- A musty odor or damp smell
- Allergy symptoms
Safety Tips for Mold Removal
When removing mold, it is important to prioritize your safety. Follow these precautions:
- Wear protective clothing: Put on a filtered dust mask to prevent inhalation of mold spores. Wear goggles to shield your eyes from irritation caused by mold spores and sprays. Protect your skin by wearing rubber gloves, long sleeves, and pants that can be laundered in hot water once you’re done.
- Protect nearby furnishings: If you are treating a large area, cover the surrounding furnishings and floor with plastic sheeting secured with tape.
- Avoid using different treatments simultaneously: Never mix the ingredients of separate DIY mold killers together or use them simultaneously in a room, as this can produce a dangerous cleaning combination.
- Stop if you feel ill: People with greater sensitivity to mold or mildew spores should avoid mold removal. If you are allergic to mold or experience allergy symptoms during the process, stop and contact your doctor.
DIY Mold Killer for Painted Walls
This homemade mold killer is suitable for painted walls or washable wallpaper, non-textured ceilings, rugs, and washable fabrics.
Ingredients:
- 2 tablespoons of borax
- 2 ounces of white vinegar
- 16 ounces of hot water
Instructions:
- Combine the ingredients in a spray bottle.
- Spray the affected area well, then immediately scrub it with a clean cloth or brush to remove the surface layer of mold.
- Reapply lightly to just dampen the area. Wait 10 minutes and wipe it with a clean dry cloth. Do not rinse.
- Leave the area to dry overnight. Inspect the next day and repeat if needed. Otherwise, wipe the spot with a damp cloth and let it air dry.
DIY Mold Killer for Textured Ceilings
Use this homemade mold killer on tile, stone, concrete, popcorn or knockdown ceilings, and cement.
Ingredients:
- 2 ounces chlorine bleach
- 16 ounces water
Instructions:
- Combine in a spray bottle.
- Apply to dampen the area but avoid dripping. Immediately scrub it with a rag, scouring pad, or brush and wipe away the residue.
- Reapply, wait 15 minutes, and rinse with a fresh cloth dampened with water.
- Let the area dry overnight and inspect it the next day. Repeat if needed.
Mold on Drywall
When dealing with mold on drywall, the best approach is to remove and replace the affected section. Bare drywall or sheetrock is porous, allowing mold to penetrate beneath the surface. But if you aren’t prepared to remove the drywall, follow these steps:
- Mist the area with the homemade bleach-based mold remover spray mentioned earlier.
- Immediately wipe the surface to remove the mold.
- Allow the area to dry for 48 hours.
- Apply a mold-blocking primer to seal the spot and prevent further mold growth. Zisner and Killz both make good ones.
Mold Prevention Tips
To keep mold from growing on your walls, it’s important to address sources of excess moisture including condensation, leaks, and humidity.
Mold from window condensation in the summer: On scorching hot days, some condensation on glass windows and doors is inevitable. To prevent mold, avoid letting the condensation sit in place. Use fans to direct airflow towards the glass or regularly wipe away the condensation with a cloth or squeegee.
Mold from window condensation in the winter: Window condensation in winter means cold outdoor air is entering your warm home. To stop it, add weatherstripping around doors and caulk any gaps around windows as part of getting your home ready for cold weather. If these measures are not possible, make it a habit to wipe or squeegee the windows daily.
Mold in bathrooms: After every shower, run exhaust fans for 15 minutes to remove excess moisture. Use a squeegee to dry off shower walls and glass doors, or shake off any excess water from shower curtains. Additionally, leave shower doors and curtains open on either side to promote air circulation and quick drying.
Mold caused by leaks: Keep a close eye on the base of toilets and beneath sinks for any signs of moisture. Monthly checks of washing machine and refrigerator water hoses are also important. Immediately address and fix any leaks you discover to prevent mold growth.
Mold from excess humidity: Use a hygrometer to monitor the humidity levels in your home. This allows you to adjust and maintain humidity within the ideal range of 30-50%. In winter, you may need to add moisture through humidifiers, while in summer, you may need to employ dehumidifiers to lower humidity levels.
By implementing these tips, you can keep the problem from returning once you’ve removed mold from your walls.
Ready to love your home again?
I have a small where my bed is the exact length of the room and touches also touches the wall/window on the third side. Unfortunately mold is on the wall behind the headboard. I have painted cement walls and the mold is green. I won’t be able to scrub it because the bed cannot be moved. Can I just spray the solution on the wall above the headboard, let it run down the wall and hope for the best??
That will most likely damage your headboard and, unless you correct the air circulation issue and improve the insulation of the wall, the mold will simply return.
Hi, we had a leak under our kitchen sink and now have mould on our brick wall. We have dried out the area and are also using a dehumidifier. What option would you say is best to tackle to mould issue? I am also based in the UK. Thanks!
I’d recommend the bleach-based solution for brick.
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
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.
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?
You can certainly try it, especially if it puts out heat since that reduces the moisture which mold needs to thrive.
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?
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.
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.
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.
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
If it’s that bad, I think you’re smart to go straight to the bleach solution. Good luck!
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!
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!
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?
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.
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
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.
I have mold on wood stained doors. Do your 2 methods work for them too?
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. 🙂
Donna might want to try putting damp rid in the closet. I hang it in my closets.
Damp Rid is wonderful. A box of sidewalk chalk works, too!
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!
It could be something from above, or moisture building up inside the closet. You should probably schedule an AC tuneup to have it inspected.
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.
dehumidifier
We had a leak in a room and now there is a white coating on a wood armoire- is that mold?
No, that’s probably water damage to the wood. Here’s how to fix it. Let me know how it turns out!
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.
And thanks for the recipe, hopefully it does the trick.
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!