I have a 4’x8’ bathroom with an exhaust fan and window. I get brown residual spots on the ceiling even when I use the vent fan. I have gone in the attic and it is dry above the bathroom. What's going on here?
Put a timer on you bath vent fan so that it runs for 20-30 minutes after a shower to better remove the moisture.
The spots are from mildew growing on the surface of the paint, most likely from condensation build up from colder months. A residue builds up on the ceiling paint surface once the mildew begins to grow from the moisture. The moisture then continues to “stick” to the residue and grow even more until it gets dark and typically shows as spots.
Just spray the spots with chlorine bleach and the spots go away – BUT lightly scrub the ceiling paint to remove the mildew residue so that the moisture does not thrive quite so quickly from the moisture.
There is likely nothing wrong with your attic, roof or venting … just a bit of good old elbow grease. Expect to see your spots return every so often. Learn more about Mosby water & moisture repair services.