Mold or mildew on the bathroom ceiling
Black or gray speckles on the bathroom ceiling are mildew, a mold that grows where steam condenses and doesn't dry out. Small patches clean off with soap and water. They'll come back within weeks, though, unless you get the moisture out of the room, which usually means running the exhaust fan longer or getting it working properly. The cleaning is the easy part. The mildew comes back unless the fan runs long enough to dry the room.
Why bathroom ceilings get moldy
Warm, moist air from a shower rises and condenses on the coolest surface, which is usually the ceiling, especially over an outside wall or under an attic. If it stays damp for hours every day, mildew grows on the paint.
The EPA says you can usually clean up mold yourself if the patch is smaller than about 10 square feet. A brown stain, peeling paint or a soft spot means water is coming from somewhere else, like a roof or a bathroom above, and that needs fixing first.
What feeds the mildew
The fan is weak, missing or turned off too soon.
Steam condenses under the attic or an outside wall.
A roof or upstairs bathroom.
Holds moisture; mildew grows easily.
| What you see | What it means | What to do |
|---|---|---|
| Small black or gray specks | Surface mildew | Clean it yourself. |
| Brown stain or bubbling paint | Water coming from above | Find the leak first. |
| Patch bigger than about 10 sq ft | Larger mold problem | Call a mold professional. |
| Comes back within weeks | Too much moisture | Fix the fan and ventilation. |
Let's fix it
- Check how big it isMeasure the patch. Spots adding up to less than about 10 square feet are a DIY job. If the ceiling is stained brown, bubbling or soft, or the mold keeps spreading, water is getting in from somewhere else.
- Protect yourselfOpen the window, turn on the exhaust fan, and put on gloves, goggles and an N95 mask. Cover the tub and floor with a drop cloth. Set the ladder on a dry, level spot.
- Scrub it offMix dish detergent in warm water and scrub the spots with a damp sponge or soft brush. Use as little water as you can so the drywall doesn't soak. Wipe with a clean damp cloth and repeat until the stains are gone.
- Dry it completelyLeave the fan running and the door open for a day or two. The ceiling needs to be completely dry before you paint, or the mildew grows right back under the new coat.
- Repaint if it's stainedIf shadows of the stain remain, prime them with a stain-blocking primer. If the old paint is glossy, scuff it lightly with fine sandpaper first. Then roll on a mildew-resistant bathroom paint. It holds up to steam much better than regular flat paint.
- Check the exhaust fanHold a single square of toilet paper up to the fan grille while it runs. It should hold the paper against the grille. If it doesn't, the fan needs cleaning, the damper is stuck, or the duct is blocked.
- Keep the moisture downRun the fan during every shower and for about 20 minutes after. Leave the door open and the shower curtain spread out to dry. Wipe the ceiling after long, hot showers until the fan is fixed.
Watch it done
- The spots are gone and the ceiling is dry
- The fan holds a square of toilet paper to the grille
- No new mildew after a few weeks of showers
Mildew back fast? The fan may be too small or venting into the attic.
If it keeps coming back
If mildew comes back quickly with the fan running, the fan may be too small for the bathroom or venting into the attic instead of outside. A contractor can check the duct.
If the ceiling is cold because there's little insulation above it, adding insulation in the attic over the bathroom cuts down condensation a lot.
What a pro typically charges (a rough estimate; prices vary by area): Professional mold cleanup for a small area typically runs $500–$1,500. Replacing a bathroom exhaust fan usually costs $250–$500 installed.
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Bathroom mold questions
Should I use bleach on bathroom ceiling mold?
The EPA recommends detergent and water for cleaning mold on hard surfaces. Never mix bleach with ammonia or other cleaners.
Why does mold keep coming back on my bathroom ceiling?
The room stays damp too long. Run the exhaust fan during showers and for about 20 minutes after, and make sure it actually pulls air.
Can I paint over bathroom mold?
Clean it off and let the ceiling dry first. Then use a mildew-resistant bathroom paint.
When should I call a mold professional?
If the patch is bigger than about 10 square feet, keeps coming back, or the ceiling is stained or soft from a leak.
What are the black spots on my bathroom ceiling?
They're usually mildew, a mold that grows where steam condenses and doesn't dry out. Small patches clean off with soap and water.