# Mystery stains on ceiling drywall



## giansean (Mar 4, 2015)

Hi All,

Noticed these stains the other day, but have no idea what's causing them. You can hopefully make out some discoloration being a long strip and two circles. The strip is where two drywall panels meet, and the circles I am sure are screws. There is a screw pop in line with the stains but that looks like a normal pop.

I immediately thought this was a water leak, as this area is right below a soffit wall where two bathtubs meet side by side. However I have access to close to the area and it is bone dry (any water leaking from the 2nd tub would also have to travel under three closely spaced joists, which I assume would be visible at some other points). I can get a better look but will have to saw up some holes to get a camera in there, but I want to rule out other causes first.

The spots are not wet and not particularly soft, other than me being able to dent them a bit w/ strong pressure, but that's true of any compounded area. I don't have a moisture meter so can't probe it. The stain was slightly yellow which "kinda" washed off but it will not totally come out.

We are in CT and have been hit by the cold snap like the rest of the US, with temps getting near 0F over the last week. The room that this is in is a laundry room so figure it gets a bit more humidity. Could this just be a cold spot where moisture is accumulating? Otherwise, I'm out of ideas lol.

Thanks!


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## Bud9051 (Nov 11, 2015)

The circles are the drywall screws (or nails) and the long strip is a seam between two sheets. You are seeing them because there is moisture as you know from somewhere. 

It could be a cold spot that is reaching the dew point and the moisture is from the air. But with 2 tubs above and related drain and vent pipes a leak is also likely. 

In some homes you have a subfloor and then a second and that moisture could be coming from in between. 

Keep looking. Infrared cameras are extremely sensitive to moisture so could possibly spot the source and they can be rented.

Others will be along
Bud


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## mark sr (Jun 13, 2017)

Sure looks like a water stain. The fix would be coating it with an oil base primer and then touch up with the ceiling paint - if the cause for the moisture is still there, the stain will come back.


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## giansean (Mar 4, 2015)

mark sr said:


> Sure looks like a water stain. The fix would be coating it with an oil base primer and then touch up with the ceiling paint - if the cause for the moisture is still there, the stain will come back.


Sigh... it is. I did a little deeper digging using the cell phone to get around corners. It must be relatively new because it's much more wet than before though luckily it has not dripped down elsewhere yet (or even there). Fortunately I can make an access hole in the bottom of a linen closet but UNfortunately it looks to be coming from a two year old new construction bathroom. If any fixtures need attention all that new tile has to come off. FML.


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## Nealtw (Jun 22, 2017)

I fixed a shower above a little stain like that. With the amount of wet wood and mold, the shower must have been leaking into the wood work for years before it showed up.


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## mark sr (Jun 13, 2017)

Hopefully it will be something minor! The main thing is to find what is leaking. You won't know until then what it will entail to correct it. Hopefully it's something you can fix from the other side of the wall or from below.


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## giansean (Mar 4, 2015)

Nealtw said:


> I fixed a shower above a little stain like that. With the amount of wet wood and mold, the shower must have been leaking into the wood work for years before it showed up.


It very well may have. It looked horrible on film last night but stuck a still camera in there today and it looks a lot better. I am wondering (hoping) that it is water running around and into holes in the tile around the fixtures, which are not well sealed off at all.

Have to cut that access hole in the linen closet (the wall to the left at 12 o'clock) so at least I can get a couple few arms up in there to see and feel. New project... yaaaaaaaaaaaaaaay!


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## giansean (Mar 4, 2015)

The hole reveals all!

So actually the leak is pretty obvious... unfortunately it's in a sucky location to fix... straight off the drain flange which is part of an overflow/drain assembly made for the tub. Can't imagine how much fun that will be to change out, if I can even get to it from there. Time to post in the plumbing section 

But now it makes sense. It dropped down onto a spot which has an old plaster ceiling on top of sheetrock. Rather than drip through it must have run into the seam and wicked up under the joists into the downstairs room. Guess I know the path of least resistance now.


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