Short answer
If the patch is smaller than about 10 square feet, you can usually clean it yourself. Open a window, put on gloves, goggles and an N95 mask, and keep kids and pets out. Scrub the spots with water and a little detergent, then dry the area completely with a fan. Find and fix the moisture, or the mold comes back. Bigger patches, or mold in soft drywall, need a pro.
Safety first
Wear gloves, goggles and an N95 mask, and keep a window open. Never mix bleach with ammonia, vinegar or other cleaners: the fumes can hurt your lungs. If someone at home has asthma, mold allergies or a weak immune system, let another person do the cleanup.
How to clean mold off a wall or ceiling
1Dark spots in a corner or on the ceiling
Mold grows where moisture sits: cold corners, behind furniture, around windows that sweat and under small leaks. A musty odor often shows up first.
Read all the steps
- Dark spots in a corner or on the ceiling. Mold grows where moisture sits: cold corners, behind furniture, around windows that sweat and under small leaks. A musty odor often shows up first.
- Check the size first. Smaller than about 10 square feet, roughly a 3 by 3 foot patch? You can clean it. Bigger, or the drywall feels soft, call a pro.
- Window open, mask, goggles and gloves. Fresh air keeps spores and fumes away from your lungs. An N95 mask, goggles and long gloves protect you. Keep kids and pets out.
- Scrub with water and detergent. A bucket of water with a little detergent and a sponge or soft brush. Rinse the sponge often and do not soak the wall.
- Dry it fully and keep it dry. Run a fan until the spot is dry. In damp rooms a dehumidifier helps keep humidity between 30 and 50 percent, so the mold does not return.
- Big patch or keeps coming back? Call a pro Especially if: the mold covers more than about 10 square feet, roughly a 3 by 3 foot patch.
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What not to do
- Do not mix bleach with ammonia, vinegar or other cleaners. If you use anything besides detergent, use one product at a time and rinse with water in between.
- Do not paint over mold. Paint on a moldy wall peels and the mold keeps growing underneath. Clean it, let it dry, then prime and paint.
- Do not soak drywall or ceiling tiles. Porous materials that stay moldy or feel soft usually have to be cut out and replaced.
Why it keeps coming back
Mold needs moisture. On walls it usually comes from a leak behind the wall or above the ceiling, or from condensation on cold outside walls and windows. Steam from showers, cooking and drying clothes indoors adds more. Run the kitchen and bath fans, move furniture a few inches off outside walls and dry anything that gets wet within 24 to 48 hours.
Spots on a bathroom ceiling
Mold on a bathroom ceiling usually means the steam has nowhere to go. Run the exhaust fan during every shower and for 20 to 30 minutes after. A water stain on the ceiling or a soft, sagging spot is different. That is a leak from the roof or a pipe upstairs, and it needs a roofer or a plumber before any cleaning.
When to call a house cleaner
- The mold covers more than about 10 square feet, roughly a 3 by 3 foot patch.
- The drywall or ceiling is soft, stained or sagging, a sign of a leak behind it.
- It comes back within a few weeks after a good cleaning.
- The mold came from flooding or sewage water, or it is inside the heating and cooling ducts.
- Someone at home has asthma, allergies or a weak immune system.
Frequently asked questions
Can I clean mold off walls myself?
Yes, if the patch is smaller than about 10 square feet and the wall is solid. Wear an N95 mask, goggles and gloves, scrub with water and detergent and dry it fully. Larger areas are a job for a pro.
Should I use bleach to clean mold on walls?
Usually you do not need it. Water and detergent clean mold off painted walls. If you do use bleach, follow the label, open a window and never mix it with ammonia, vinegar or other cleaners.
Does vinegar kill mold on walls?
White vinegar can help on small spots on painted walls. Spray it on, wait about an hour, wipe and let the wall dry. Never use it together with bleach, and rinse with water before switching products.
Why does mold keep growing in the corner of my ceiling?
Cold corners collect condensation, especially on outside walls and above showers. Lower the humidity with fans or a dehumidifier, keep air moving and check for a leak from the roof or a pipe above.
Is black mold on walls dangerous?
Any mold can trigger allergies, asthma and irritation, whatever its color. You do not need to test what kind it is: clean small patches safely and call a pro for large ones.
Can I just paint over mold?
No. Paint over mold peels, and the mold keeps growing underneath. Clean it, dry the wall fully, then prime and paint.
Sources
Checked October 24, 2026. Requirements and recommendations change: confirm them on the source site.