Odd bathroom condensation/ectoplasm stains.
November 7, 2006 12:48 PM   Subscribe

In colder weather, while taking a shower, water eventually condenses on our bathroom walls (even with the exhaust fan on). The odd thing, which I cannot figure out, is that a faint yellowish substance appears from nowhere and runs down the wall. I wouldn't notice this on the semi-gloss lavender paint, but it pools on the white wainscotting below. It's an old house but was painted a few years ago and the paint seems clean on the surface. I've wiped down the walls, but it doesn't seem to help. What is the yellow stuff?

P.S. There is no odor to the yellowish substance (almost an orange) and it easily wipes off when still wet.
posted by _sirmissalot_ to Home & Garden (24 answers total) 5 users marked this as a favorite
I get this too in my bathroom and have no idea why - if it helps in identifying it, my house is Victorian but the paint in the bathroom is again a few years old. It wipes off without staining when wet as _sirmissalot_'s does. It forms in odd isolated rivulets.
posted by greycap at 12:54 PM on November 7, 2006

Minerals in the water? Like hard water stains?
posted by agregoli at 12:55 PM on November 7, 2006

I have gotten this in other rooms - I just repainted my entire house within the last year and had it happen in the closet in what used to be the previous owners bedroom (and has the attic access panel in the ceiling). I guessed that she was a smoker and this was nicotine/tar that had attached to the paint underneath.

Could your house have had oil heat at one time? That leaves a residue on the walls that wouldn't be contained with repainting.
posted by blackkar at 1:05 PM on November 7, 2006

If the bathroom was wallpapered at some point, there may be wallpaper adhesive under the paint, and it comes to the surface when wet. Serious priming, or using Killz or BIN, might help.
posted by theora55 at 1:07 PM on November 7, 2006

We had this at one time in our bathroom after having painted the walls with the standard interior grade Behr paint from Home Depot. We have since repainted, starting with the top-of-the-line KILZ primer (KILZ Premium), then with Sherwin-Williams' top of the line Duration paint, and have not had the problem since.

So my un-expert advice would be to use a high quality primer then a higher quality paint designed for bathroom/kitchen applications where the painted surfaces are likely to get wet or at least damp.
posted by pitchblende at 1:20 PM on November 7, 2006

Do you smoke? We get this in our bathroom, but I've always put it down to nicotine collecting in the vapors because we're both smokers (not that I smoke in the bathroom). It would be interesting to find out if it's something else because it's exactly as you describe and it is only in the bathroom.
posted by floanna at 1:23 PM on November 7, 2006

I have this too, or a very similar yellow gooey substance, due to poor bathroom ventilation in my 50-ish-year-old university housing. I call it mold, but I have no good reason for thinking so. I'm sure it could equally well be minerals or adhesives leaching out of the drywall.
posted by RogerB at 1:39 PM on November 7, 2006

Response by poster: We're not smokers and the people who lived in this house for a few years before us weren't smokers either.

I doubt it's minerals since the water is from the city supply and plus, how would they carry in water vapor? I don't notice any staining in tub or shower walls.

The house was oil-heated for a long time (it's now natural gas)--actually coal-heated before that. I can't imagine any residue would have that kind of staying power, though. But who knows? The whole thing is weird.
posted by _sirmissalot_ at 1:49 PM on November 7, 2006

Dab some up with a Q-tip (not the anti-bacterial kind or with a paper towel) and put it into 1/2 inch of milk on the kitchen counter for a couple of days. If you see lots of yellow, it's probably a living thing, most likely bacteria.
posted by jamjam at 1:51 PM on November 7, 2006 [1 favorite]

This happened in the bathroom of an apartment I used to rent in an older Victorian-style house (1870s maybe?). The place had a fresh coat of paint immediately before I moved in. I figured it was something in the paint because it dripped from the wall AND the ceiling, which were both painted with the same paint. It also seemed to decrease (but not go away totally) over the two years I lived there. I found it kind of gross, especially when two or three people would take showers back to back and it would drip from the ceiling. Yuck.
posted by flying kumquat at 1:58 PM on November 7, 2006

My last apartment had this issue in the bathroom too, but I never figured out what the substance was. I never smoked there, and I don't think the previous tenant did either. The building was relatively new (1950s-ish) and had baseboard radiator heating, so I don't think residues from coal or gas heating had anything to do with it. Weird, and gross, but I guess I'm glad other people have seen this phenomenon.
posted by vytae at 2:08 PM on November 7, 2006

I'm hoping someone has an answer. This happened to me in my last apt. here in San Francisco. And, yes, it was an older Victorian apartment, an old bathroom with white-painted wood walls and a clawfoot tub. The yellow stuff never dripped from the celing but it did drip down the walls. I could never figure out where it came from - it seemed as if it was seeping out of the walls.

I remember Googling and asking people back then and never getting an answer....
posted by vacapinta at 2:08 PM on November 7, 2006

Hair spray residue?
posted by Kid Charlemagne at 2:14 PM on November 7, 2006

You know, I have a similar thing but it's on the tiles in my shower. It can be easily cleaned off but I have never identified the substance either. I haven't noticed it on the wallpaper, and my house was built in 1983.

BTW, I think the yellow stuff on walls from cigarettes is the tar, not the nicotine, no?
posted by forensicphd at 2:17 PM on November 7, 2006

Best answer: As a follow-up to my earlier response, I found this on the Devoe paints website that agrees with jamaro's comment:

I have noticed in the bathroom after recently painting, steam seems to leave an oily golden-yellow residue dripping down the walls. Is it something that is leaching out of the paint? What can I do to stop this?

What is happening in your bathroom is a common paint problem called "surfactant leaching."

The following is from the Paint Quality Institute

Surfactant Leaching:

Concentration of water-soluble ingredients on the surface of a latex paint, typically on a ceiling surface in rooms that have high humidity (e.g., shower, bathroom, kitchen); may be evident as tan or brown spots or areas, and can sometimes be glossy, soapy, or sticky.

Possible Cause:

All latex paint formulas will exhibit this tendency to some extent if applied in areas that become humid (bathrooms, for example), especially in ceiling areas.


Wash the affected area with soap and water, and rinse. Problem may occur once or twice again before leachable material is completely removed. When paint is applied in a bathroom it is helpful to have it dry thoroughly before using the shower.

If you have an exhaust fan use it regularly and if possible open windows.

posted by pitchblende at 2:20 PM on November 7, 2006 [1 favorite]

I also say the water-based paint is leaching surfactants. See this pdf, which has a very good explanation. Bathrooms are prone to leaching because of the sheen of the paint, humidity, and lack of air circulation.

In foggy San Francisco, leaching of exterior latex paint can continue for a few years if the paint is applied in humid weather and there's a lot of humidity while the paint is drying and curing. So don't expect that the paint will cure properly any day now.

There are two things you can do, other than live with it. Wash the walls and repaint with oil-based paint, or repaint with latex when you know the humidity will be low for a few days. For the first week, increase air circulation and take cooler, shorter showers.
posted by wryly at 2:25 PM on November 7, 2006 [1 favorite]

I doubt it's minerals since the water is from the city supply and plus, how would they carry in water vapor? I don't notice any staining in tub or shower walls.

Boy, that raises another question for me - why WOULDN'T minerals in water carry in water vapor...can anyone answer that for me?
posted by agregoli at 2:38 PM on November 7, 2006

I agree with the 'it's the paint' people. We had that exact problem in our bathroom at my parents house.
posted by jacquilynne at 2:52 PM on November 7, 2006

"...Boy, that raises another question for me - why WOULDN'T minerals in water carry in water vapor...can anyone answer that for me?"
posted by agregoli at 5:38 PM EST on November 7

Because water vapor is literally, water in gaseous form. If you distill water (vaporize it with heat), any dissolved material with a higher boiling point than water remains behind in the pot, and so, if you live in a hard water area, you see the previously dissolved calcium, sulphur, iron or other minerals in discoloration rings. The same process happens by evaporation of water, albeit more slowly, or in situations where shower steam provides the water vapor.

However, if shower spray hits the walls, that's another story. By that mechanism, since the water carrying the dissolved minerals is hitting the wall, then, yes, the minerals could be deposited on the wall.
posted by paulsc at 2:58 PM on November 7, 2006

agregoli - I think that when water gets hot enough to rise as steam, it's actually been converted into a gas-form and thus is pretty pure H20. I think that's what 'distilling' is all about. BUt it's been a long time since grade school....
posted by Rubber Soul at 3:02 PM on November 7, 2006

adding to paulsc's and Rubber Soul's answers ... the more complete answer is that everything dissolved in water (and the water) has a different tendency to evaporate (a different boiling point, a different vapor pressure). Most of the time, the water is the most volatile stuff in the pot, so it'll evaporate (or boil off) leaving everything else behind. Some small amount of the other stuff might evaporate as well, depending on what it is. On the other hand, alcohol is more volatile than water, so you can heat an alcohol-water mixture up to a point where the alcohol is coming off pretty quickly and the water is coming off very slowly. Condense the vapor onto a nearby cold object and you have distilled liquor.

It gets more complicated than that, but that's the basic idea.
posted by hattifattener at 12:00 AM on November 8, 2006

I have the same problem - thanks for providing some answers. No I just have to sort out that mould...
posted by jonesor at 6:30 AM on November 8, 2006

Curses! "Now", not "no"
posted by jonesor at 6:31 AM on November 8, 2006

Thanks for the explanation...
posted by agregoli at 6:58 AM on November 8, 2006

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