Water marks on wall near the ceiling


Old 11-22-10, 09:15 PM
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Water marks on wall near the ceiling

I noticed today what looks like water drip marks on the inside walls in one of my bedrooms and a bathroom on the 2nd floor. It's right at the top, near the ceiling and it's only on the outside walls, and what looks like just in these two rooms. The other two rooms on the same floor (2nd floor) seem fine though maybe I just can't see it. I tried wiping it, but it wouldn't wipe off.

I live in Canada and of course at this time of the year it is getting cold, and unfortunately our heating is terrible on the 2nd floor as we just have forced air that doesn't blow enough.

Any idea what is causing these water-like marks?
Old 11-23-10, 06:13 AM
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Sounds like you have a leak

Not fun
Old 11-23-10, 09:26 AM
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Hi Snaffoo,
There are only a few sources for water, rain, condensation, or a leak in your water system.

Rain: look for details on the roof or windows above the problem area.

Condensation: Although it is early in the cold season and I assume you have lived there for more than one winter, any condensation issues should be associated with something that was changed. Lights, electrical work, bath vents, insulation, or anything that may have allowed warm moist air to enter a cold space. If there is a heat duct in that area where warm moist air is leaking into the walls, that can provide a source of moisture. It would also result in reduced heat flow to where it is supposed to be going. You mentioned the second floor doesn't blow enough.

Water Pipes: Water or drain pipes, toilets and suck can be leaking. The point at which you see the moisture can be several feet horizontally from the source so check everything above and to the sides of that area.

Did you have this problem last year? Did it just start? Have you made any changes this year in that area?

Old 11-23-10, 06:52 PM
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Old 11-23-10, 07:11 PM
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I had a similar stain because the blown in insulation in my walls had settled and left voids at the top. The area with the void gets colder than the surrounding wall, moisture condenses more easily on the cold surface, and dust collects on the condensation. This causes what a lot of people call "ghosting".

The stain actually looked like a water mark, but it was just the shape of the void that made it look that way. I could also see some of my studs and drywall screws due to thermal bridging, which is basically the same principal.

My stain was very similar to the dark area of the above photo, only much fainter.


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