I have a bathroom in our 1930's house that doesn't have an exhaust fan...and two teenage boys who take ridiculously long steamy showers. We had some mold issues on the ceiling, and some of the ceiling paint was cracking anyway, so I set about fixing things. I scraped all the old paint away back to the plaster. I primed with Zinsser Perma-White mold resistant primer, then painted with two coats of Zinsser ceiling paint. Looked great.

But now every week or so I walk in there to find these gross, sticky orange dots all over the ceiling. They wipe away and leave no stains, but they look awful.

Googling seems to indicate these are surfactants from the paint? Is that consistent with your experience?

I'm planning on putting in an exhaust fan in the spring... have to penetrate the brick exterior and don't feel like doing that when it's freezing outside... which I hope will help, but is there anything else I can do to stop this?

Update: here's a picture of the ceiling after a week of no one using the shower at all

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  • 1
    Install a timer operated shutoff valve on the hot water line. ;)
    – FreeMan
    Dec 30, 2020 at 0:57
  • I have seen orange fungus on wood do you have any photos? I use hydrogen peroxide 3% and water. This solution is good at killing mold and not discoloring surfaces.
    – Ed Beal
    Dec 31, 2020 at 2:59

2 Answers 2


I hate to burst your bubble but I have one of those antique houses and unlike yours it has a vent - in the wall - which is probably what you are thinking of doing - but the vent doesn't do jack squat. The only bathroom vents that work right (in my experience) are ones in the ceiling. When you install yours if you take the ceiling down and put the vent pipe exiting the house above the ceiling it will work otherwise you will continually have problems.

I just ignore the ceiling then once a year get up there with 50/50 bleach/water and wipe it all down. The bleach soaks into the paint and is nasty enough that the mold dies immediately on touching the paint even months later. Ultimately nature manages to break down whatever residue the bleach leaves behind and the mold will finally start then I attack it again. It's a battle of nature vs chemicals. Ignore the "cap of bleach in a gallon of water" recommendations those are for wus ses.

  • I agree that ceiling exhaust fans do better, but I don’t like the smell of bleach 1930 farm house here also.
    – Ed Beal
    Dec 31, 2020 at 3:05
  • Updated OP with a picture of the current state of the ceiling. Those blotches wipe off with a damp cloth...but they'll be back.
    – jerH
    Jan 12, 2021 at 21:23

If the orange anomaly's are produced from the paint it may not be dried enough. If so once it has dried completely it should be impervious to moisture.

If it is indeed surfacant's, as someone suggested I would think their source would be from steam laden with soap or shampoo. These two common cleaners are usually produced with surfacant's. Meaning they contain substances that enable the breakdown of oil (if I remember High School Chem 101 correctly).

Either way the solution is venting. While waiting for fan have the boys crack the window before they exit the room.

  • I thought surfactants broke down water tension, I know things like jet dry is a surfactant that breakers water tension so dishes won’t spot. Maybe there are similar ones for oil ?
    – Ed Beal
    Dec 31, 2020 at 3:16

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