Common causes
- No exhaust fan, or one that’s too small or too noisy to use
- A fan that vents into the attic instead of outdoors
- Fan not run long enough after showers
- A leak from above or from a roof vent
- Cold AC supply air hitting a warm, humid ceiling
The fix
- Install a quiet fan sized for the room, ducted to the roof or an exterior wall
- Add a timer or humidity-sensing switch so it runs long enough
- Replace stained or soft drywall with moisture-resistant board
- Use a mold-resistant bathroom paint on the ceiling
Common questions
Can I clean bathroom ceiling mold myself?
Small surface spots can usually be cleaned with detergent and water and the area dried. If it covers a large area, keeps returning or the drywall is soft, the moisture source needs fixing and the drywall replacing.
Where should a bathroom fan vent?
Outdoors, through the roof or a wall. A fan that dumps moist air into the attic can cause mold on the roof deck.
Sources
This guide is general information, not legal, tax or financial advice. Rules change; confirm details with the agency named in the sources or a licensed professional.