How to remove mold on plaster walls?

Candice Cleaver
by Candice Cleaver

I need your help with a worrisome problem, I have mold on my plaster wall. I would love to know what causes mold growth on plaster walls and if it is a health hazard. Is there any way to prevent this issue? Any advice on how to get rid of it is appreciated.

Mold on plaster walls

  21 answers
  • You need to find the source of the mold. Plaster wall indicate an old house. Check for leaks or moisture around the sill. Once that is found and taken care of, the mold on the wall can be dealt with...vinegar will penetrate the plaster and kill the mold.

  • Janice Janice on May 30, 2023

    HI Candice, mold needs moisture to form. Perhaps you have a leak that is causing the mold on your plaster. When my basement flooded the company who rescued it got rid of the water and then used bleach and water to spray all the areas that had gotten damp. I think 1 cup of bleach to 1 gallon of water. Some mold is very dangerous if let untreated. I'm linking a government site that will inform you better about the problem. Hope it is helpful to you.

  • GrandmasHouseDIY GrandmasHouseDIY on May 30, 2023

    Once you eliminate the source you will want to scrub the area with white vinegar before repainting. If it is in a damp environment (like a bathrom) I would suggest a mold and mildew resistant primer and than paint and that should really help keep mold from showing up again!

  • William William on May 30, 2023

    You need to find what is causing the mold to form. Mold needs moisture. Bleach will clean the mold. Rinse well. Then use vinegar to kill mold spores. Rinse well. Do not mix bleach and vinegar together, Harmful fumes will form.

  • Kathy Gunter Law Kathy Gunter Law on May 30, 2023

    First, you can clean the area with vinegar to kill mold spores. Then wipe clean and prime with a stain blocker, I use Bullseye 1-2-3. Then you can paint over that.

    As for prevention, you might need to put in a dehumidifier. Keep the air flowing in the area and moisture level at a minimum. Other devices would be a product like Damp-Rid placed in the area. I purchased a small dehumidifier from WalMart and put in a bedroom that amazed me as to how much moisture is pulled from the air each day.

    • Candice Cleaver Candice Cleaver on Jun 04, 2023

      Thanks Kathy, I need to find the source of the moisture that is causing the mold and yes, maybe a dehumidifier for prevention.

  • You will definitely need to use a primer before painting after you get it cleaned up. We've used Kilz and it works very well.

  • Cheryl A Cheryl A on May 31, 2023

    Mold on plaster walls on the other hand are cleanable since it is not a food source, and not porous. The mold is usually feeding on your paint and dust.

  • Redcatcec Redcatcec on Jun 01, 2023

    First find out what the moisture source is for the mold, you may be able to control the growth with a dehumidifier if you can;t find the source. Start with vinegar to kill the mold spores, then wipe off with water. Best use bleach to remove the stain. Do not mix the bleach and the vinegar, it will cause a caustic gas to form.

  • Deb K Deb K on Jun 01, 2023

    Hi Candice, hope this helps you out. Vinegar is an effective cleaning solution for bathroom mold and mildew. Spray a wall with full-strength vinegar or a diluted mix of vinegar and water and scrub or wipe down at least once a week to discourage fungal growth.

    Or you can use a mold specific product

  • Mogie Mogie on Jun 01, 2023

    First, spray a bleach solution to attack mold stains on walls.

    Spray mold on walls with white vinegar to get to the root of the problem.

    But first find the problem and fix or this will happen again.

  • To prevent this from happening, and the way to start is finding what's causing the mold. There's moisture getting in the wall from somewhere and that has to be repaired first. Once that's fixed, you can lightly spray with bleach to clear up the mold, use a waterproof primer, and then paint.

  • Plasterboard is made up of layers, thus using bleach or even a mold wash will only get rid of the mold on the surface. The biggest problem is that there is active mold on the plasterboard. Unfortunately, replacing the plasterboard is the only method to permanently get rid of mold.

  • Yamitanny Yamitanny on Jan 25, 2024

    First off, it could be due to high humidity or water leaks, so maybe check for those. Mold isn't usually a health hazard unless you have allergies or respiratory issues, but better safe than sorry. Prevention-wise, good ventilation is key, and fixing leaks pronto helps a ton. Now, tackling the existing mold – I recently had success with a DIY mix of white vinegar and baking soda. Just be sure to wear a mask and open a window; it can get a bit pungent. If it's a bigger issue, considering Murrieta flood damage services could be a lifesaver. I heard good things about a flood management service provider in the area. Maybe they can assist?

  • Betsy Betsy on Jan 25, 2024

    Hi Candice: You have to be very careful with this as it can get into your lungs, so wear a mask when cleaning. You need to know if it's mold or mildew. Look here:

    What's the Difference? Mold vs. Mildew (

    Here are some helpful sites:

    How to Remove Mold on Drywall - This Old House

    Mold On the Walls: Why It's There and How to Get Rid of It - Bob Vila

    How To Remove Mold From Drywall - Painted And Unpainted (

    If you have a problem with moisture, you can get some dehumidifiers at the Dollar Tree. I use them all of the time and they work great! You can write on the top when you installed them and keep a check to see how long it takes to fill up. If it's fast, then you may have a serious leak somewhere.

  • SalvatoreBarron SalvatoreBarron on Feb 20, 2024

    I had a similar situation a while back, and it turned out to be quite the puzzle. Mold on plaster walls can happen due to moisture, leaks, or poor ventilation. First, ensure there's no water source causing it. As for health concerns, it's essential to tackle it promptly. I stumbled upon this fantastic mold removal company in Houston, TX. They really know their stuff! You might want to check out for some useful tips too. For prevention, try improving ventilation, fixing leaks, and keeping humidity levels in check. As for removal, a mix of white vinegar and baking soda worked wonders for me. Just be sure to wear protective gear!

  • Johnavallance82 Johnavallance82 on Feb 21, 2024

    If it is in a corner then it probably is because the air is moist and there is not enough ventilation or movement of air!

  • Kathy Gunter Law Kathy Gunter Law on Feb 22, 2024

    I would have it tested. Prevention would be a dehumidifier if you know what's causing it. Wondering what is on the other side because it could be coming from other room. White vinegar will kill mold spores. Then you can try to lift the stain with hydrogen peroxide and finally prime and paint over it.

  • Dee Dee on Feb 24, 2024

    Moisture causes mold. You can either use white vinegar or bleach on the stain and scrub with a magic eraser.