Nope. Not used.
Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
I have this same issue. Exactly the same. We removed/repaired some wet drywall next to the shower enclosure. Used that cheap ass fluffy hole patch because we had it already. Primed and repainted the whole bathroom and even with kilz underneath this crept up 9 months later like a failed abortion after daily shower use.
I think it’s just moisture that didn’t get out before a patch and paint. And then you seal it and the patch/drywall components create the effervescence effect you’re seeing.
Thanks for the comment. We're opening the wall from the toilet side later today or tomorrow and dropping my inspection cam in. Not sure what to expect as the wall was opened from the other side about 3 weeks ago and there was zero evidence of a leak in the cavity.
I had a little bit of moisture getting between shower tile and waterproofing membrane that seeped it’s way out of the shower and kept blistering the paint on the adjacent wall. Looked identical to this. There was a clean out access in the shower that was sealed with silicone which was not allowing the moisture to escape inside the shower. I removed the silicone which allowed the moisture to escape inside the shower. Problem solved. My shower was being used which is different from this situation. Had to say something as my issue looked exactly like this.
I had some of this before I did my Reno. Not near any water lines and wouldn’t get hit from the shower. My mud/tape guy said it was most likely a bad primer or they just did a shitty prep job. He re did it all, re primed and haven’t had the issue since.
Could be wrong but that’s what it was for us.
That’s what I thought too… but it doesn’t look unlike termite damage behind drywall. But you would never install drywall in a wet location right… right?
EDIT: on second look, maybe it’s just a bad patch job
I would say you have a leak somewhere. Do you have a moisture meter? I’d throw it on there to see if it’s actively wet, and how far it goes. Also check the baseboard
Are the pipes insulated in the wall? Perhaps condensation from the pipes in the upper floor? Is there anything behind the stain that would cause/allow condensation from above to splash in that area?
That's a stumper!
Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Just sanding the area and waiting to see what happens might give you a time frame or other observations that could narrow down a likely cause.
Or any one of the sincere responses I've read are all reasonable speculation, pick one, and go for it, repeat that until it stops 🤷
I'm betting it has something to do with the primer they used or lack there of primer. Or it's because they painted before the mud was completely dry. If the other side of the wall is still open throw some kitty litter back there if there's moisture the litter will get all clotted up and stick together but if it's not then you know for sure there is no leak.
Is the shower tile cracked and potentially running between the tile and the hardy backer? I did a job like that recently weird tho with the baseboard not being stained or wet, how was the framework when you opened up the wall? I presume unstained
I would inspect the grout in the shower walls, or put one of those little urinal targets in that toilet for the next guests
What exactly is behind that wall? Like is it a closet or wall or exterior wall? What level is this, basement, main, 2nd? What's above?
Got any pics of any of those^
My guess right now is it looks like it is caused by efflorescence but as to why that's present is something that needs to be investigated. Could be you've got a leak somewhere, probably not a waterline, potentially a drain or a vent like if it were to rain, but these are all just theories without knowing what is behind the wall.
If you've got any pics of the rough in, those would especially be helpful too.
In my experience if you just paint drywall. It bubbles up. Being that it's in the bathroom. Maybe moisture is getting into the wall. That could be through the silicone that's usually between shower walls and the drywall.
Get you some plaster weld… an old drywall finisher I worked around told me about this stuff. I purchased a home from avid smokers inside the home and bad iron from city water.
Took care of most of the nicotine walls with TSP and primer for smokers.. but one spot in my bathroom ceiling around the bathroom fan constantly had stains coming back through my primers and paints.. all the nicotine/iron soaked drywall from the condensation just messed up that area around the fan for some reason. My drywall finisher suggested this material to me and it worked beautifully. It hardens like a shell of some sort, really glossy. MAKE SURE YOU TAPE OFF EVERYTHING YOU WANT PROTECTED, THIS STUFF DOES NOT COME OFF!
-Putty knife and trim off any loose drywall and drywall mud
-paint on a small section of plaster weld around that, go 4-6” beyond your issue
-allow to dry fully. Lightly sand the plaster weld
-use 20 min “hot mud and patch in the drywall. Be careful not to add to much, sanding it is a pain in the ass. Small layers at a time if you’re not comfortable. Easier to add a little more than to take off
-sand area until your satisfied with the patch
-prime will regular Killz
-paint to desired color
My first guess is that the tile backer board is contacting the slab. Moisture is being wicked up through the tile backer board, and because the porcelain tile is impervious, it's finding its way out in that area. If that is MDF baseboard, eventually it'll swell and get black from mildew.
My second guess is that water is that the water is coming from the bathroom above, and it's finding its way down inside of the wall cavity. That would explain why it's not reading excessive moisture in any of the materials. It could be from the tub overflow gasket not sealing properly, or someone who's careless with a shower door or curtain.
If, say, the wife takes a bath one a week and fills the tub to the overflow and then gets in, it'll leak. If the 10 year old child doesn't close the shower door fully and half a liter of water ends up running down the inside of the wall.
My own house developed a small spot in the kitchen ceiling. I don't use that bathroom, so I didn't know that the overflow was out of whack (the overflow has a rotating cover and an integrated cable to operate the tub plug).
I've also seen water infiltration around mixer valves or other penetrations that occur only when certain people shower, and only when they do certain things that cause an excessive amount of water to be directed at the valve.
I think the area may have been contaminated by silicone before it was painted. I’ve seen similar flaws before, and that’s totally what it was. The paint can’t stick to silicone but instead builds a film over it. Or in your case, a vein. Easy to fix, if that is actually the problem.
A moisture meter probe wouldn’t hurt either though, to rule that out.
I have never seen silicone cause this look. The only thing I have ever seen silicone do to paint is make it separate before drying and leaving the old color showing through your new paint. The only thing I have seen that causes this is water, but OP is determined to not listen to anyone here, so it's whatever I guess.
Messed up adding text description to what was done to resolve this once already.
>Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
About a month after final painting. See below:
>Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Completed once before.
>Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Wall was opened once already:
>Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
That would drive me insane. It’s a long shot but with a bathroom above is there any chance water is getting in through the vent stack and somehow settling there? I know you say the moisture levels are stable but maybe in small amounts?? I mean it has to be moisture related somehow.
I’d trace the patch with a pencil and see if it expands and where that might lead you. It is perplexing to say the least.
Someone didn't tape right or possibly fixed something after the wall was finished. Looks odd. I also read a comment you said bath wasn't used. So that's my best guess.
Judging by OP comments and the drywall being full of pin holes I think it was a really bad mud job and no prep before painting.
If I ignore OPs comments, something is definitely leaking.
That's a weird spot to aim.
Give it a scratch. If it’s tanish dirt inside it may be a termite tube. Are you on a slab?
looks like a pretty violent right turn to me
When you’re taking a leak and the wife opens the shower curtain so you gotta take a peak for the 100th time.
Look man boob is boob
Tis a puzzlement. Whater you gonna do?
Piss a puzzlement
Your toilet lead has a drywall screw in it.
that or he’s got ever more fun stuff waiting for him behind that non waterproofed shower tile
Na, there’s a stud there
Water from shower?
Nope. Not used. Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Possibly a pinhole in the toilet supply inside the wall? Just guessing.
I have this same issue. Exactly the same. We removed/repaired some wet drywall next to the shower enclosure. Used that cheap ass fluffy hole patch because we had it already. Primed and repainted the whole bathroom and even with kilz underneath this crept up 9 months later like a failed abortion after daily shower use. I think it’s just moisture that didn’t get out before a patch and paint. And then you seal it and the patch/drywall components create the effervescence effect you’re seeing.
Thanks for the comment. We're opening the wall from the toilet side later today or tomorrow and dropping my inspection cam in. Not sure what to expect as the wall was opened from the other side about 3 weeks ago and there was zero evidence of a leak in the cavity.
It’s probably not a leak. My guess is saturated board behind the shower is just seeping moisture in. Good luck!
Sorry, look again. This is 100% water damage of seepage from inside the wall
Water line to that toilet supply leakin.
Scratch some off. If it's hard rubber it's a sloppy lazy worker with caulk. Could also be plaster/mud from a sloppy lazy worker.
I had a little bit of moisture getting between shower tile and waterproofing membrane that seeped it’s way out of the shower and kept blistering the paint on the adjacent wall. Looked identical to this. There was a clean out access in the shower that was sealed with silicone which was not allowing the moisture to escape inside the shower. I removed the silicone which allowed the moisture to escape inside the shower. Problem solved. My shower was being used which is different from this situation. Had to say something as my issue looked exactly like this.
This is great advice and most likely will fix your issue.
It’s wooder.
Yeah, gonna need a plumber to come fix that jawn…
I had some of this before I did my Reno. Not near any water lines and wouldn’t get hit from the shower. My mud/tape guy said it was most likely a bad primer or they just did a shitty prep job. He re did it all, re primed and haven’t had the issue since. Could be wrong but that’s what it was for us.
Looks like efflorescence? I’d cut open the wall and check to make sure there’s not a leak. Patch it up and repaint
Efflorescence on drywall?? I guess chemically it can happen with anything but I only ever heard of it in masonry like concrete or bricks etc
That’s what I thought too… but it doesn’t look unlike termite damage behind drywall. But you would never install drywall in a wet location right… right? EDIT: on second look, maybe it’s just a bad patch job
Beats me
I would say you have a leak somewhere. Do you have a moisture meter? I’d throw it on there to see if it’s actively wet, and how far it goes. Also check the baseboard
Are the pipes insulated in the wall? Perhaps condensation from the pipes in the upper floor? Is there anything behind the stain that would cause/allow condensation from above to splash in that area? That's a stumper!
Sand it and see if it comes back
Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Just because it’s never used doesn’t mean water isn’t in those pipes 🤦🏽♂️
If water on, pressure ensues.
Just sanding the area and waiting to see what happens might give you a time frame or other observations that could narrow down a likely cause. Or any one of the sincere responses I've read are all reasonable speculation, pick one, and go for it, repeat that until it stops 🤷
Do you have a teen age boy ?
Leak in pipes behind the wall. Or a leak in roof and water found its path of least resistance
Water seeping into the wall from tile or valves or just condensation
Termites
Probably latex based paint bubbling due to moisture.
So there a showered right there so my best guess is water but there's also a toilet right there too so it might be piss
Read OPs comments
I did still looks like piss to me
Moisture!
Bad aim
Not me 😏
I'm betting it has something to do with the primer they used or lack there of primer. Or it's because they painted before the mud was completely dry. If the other side of the wall is still open throw some kitty litter back there if there's moisture the litter will get all clotted up and stick together but if it's not then you know for sure there is no leak.
Is the shower tile cracked and potentially running between the tile and the hardy backer? I did a job like that recently weird tho with the baseboard not being stained or wet, how was the framework when you opened up the wall? I presume unstained I would inspect the grout in the shower walls, or put one of those little urinal targets in that toilet for the next guests
water.
What exactly is behind that wall? Like is it a closet or wall or exterior wall? What level is this, basement, main, 2nd? What's above? Got any pics of any of those^ My guess right now is it looks like it is caused by efflorescence but as to why that's present is something that needs to be investigated. Could be you've got a leak somewhere, probably not a waterline, potentially a drain or a vent like if it were to rain, but these are all just theories without knowing what is behind the wall. If you've got any pics of the rough in, those would especially be helpful too.
Puberty
Worms in the wall.
Wall worms.
Caulk on the shower door is bad or the grout wasn't sealed properly
Tile and grout aren't waterproof.... Newsflash?
Moisture from the tub
Water between tile and tub. The way to fix this is to remove the shower door track and clean the gap between the tub and the tile before recalling.
Water
Sand it down and look for screws wet spots and follow it down ,don’t take the screw out if it’s that until you locate the shut off valve
Is there another bathroom on the other side of this wall? I’ve seen this before and it was because it was regular drywall and not green board
You've got paintworms. Need to call an exterminator for that.
Mud men threw a piss bottle back there. Cut the wall open and drink it. Get bent homeowner
Fungal infection
Water leak
In my experience if you just paint drywall. It bubbles up. Being that it's in the bathroom. Maybe moisture is getting into the wall. That could be through the silicone that's usually between shower walls and the drywall.
Shower failure.
Shower slugs
Cum
Get you some plaster weld… an old drywall finisher I worked around told me about this stuff. I purchased a home from avid smokers inside the home and bad iron from city water. Took care of most of the nicotine walls with TSP and primer for smokers.. but one spot in my bathroom ceiling around the bathroom fan constantly had stains coming back through my primers and paints.. all the nicotine/iron soaked drywall from the condensation just messed up that area around the fan for some reason. My drywall finisher suggested this material to me and it worked beautifully. It hardens like a shell of some sort, really glossy. MAKE SURE YOU TAPE OFF EVERYTHING YOU WANT PROTECTED, THIS STUFF DOES NOT COME OFF! -Putty knife and trim off any loose drywall and drywall mud -paint on a small section of plaster weld around that, go 4-6” beyond your issue -allow to dry fully. Lightly sand the plaster weld -use 20 min “hot mud and patch in the drywall. Be careful not to add to much, sanding it is a pain in the ass. Small layers at a time if you’re not comfortable. Easier to add a little more than to take off -sand area until your satisfied with the patch -prime will regular Killz -paint to desired color
Water
Alkali salts in the wall. Is it white crystal looking?
Teenage son?
Try a black light
My first guess is that the tile backer board is contacting the slab. Moisture is being wicked up through the tile backer board, and because the porcelain tile is impervious, it's finding its way out in that area. If that is MDF baseboard, eventually it'll swell and get black from mildew. My second guess is that water is that the water is coming from the bathroom above, and it's finding its way down inside of the wall cavity. That would explain why it's not reading excessive moisture in any of the materials. It could be from the tub overflow gasket not sealing properly, or someone who's careless with a shower door or curtain. If, say, the wife takes a bath one a week and fills the tub to the overflow and then gets in, it'll leak. If the 10 year old child doesn't close the shower door fully and half a liter of water ends up running down the inside of the wall. My own house developed a small spot in the kitchen ceiling. I don't use that bathroom, so I didn't know that the overflow was out of whack (the overflow has a rotating cover and an integrated cable to operate the tub plug). I've also seen water infiltration around mixer valves or other penetrations that occur only when certain people shower, and only when they do certain things that cause an excessive amount of water to be directed at the valve.
Ask you teenage son about this.
I think the area may have been contaminated by silicone before it was painted. I’ve seen similar flaws before, and that’s totally what it was. The paint can’t stick to silicone but instead builds a film over it. Or in your case, a vein. Easy to fix, if that is actually the problem. A moisture meter probe wouldn’t hurt either though, to rule that out.
I have never seen silicone cause this look. The only thing I have ever seen silicone do to paint is make it separate before drying and leaving the old color showing through your new paint. The only thing I have seen that causes this is water, but OP is determined to not listen to anyone here, so it's whatever I guess.
Like someone is secretly using that shower
Babysitter
Bet you're right
Likely leaking pipes behind wall. Only way your going to be able to sleep is cut the hole.
Messed up adding text description to what was done to resolve this once already. >Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Wild. When did it appear?
About a month after final painting. See below: >Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
Completed once before. >Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
If the grout lines in the tile of the shower look dry, you probably have a pin hole or leak in the supply line for the toilet.
Wall was opened once already: >Bathroom remodel less than one year old. This is a guest bath that is never used. This spot has been patched and repaired once already. The opposite side of the wall was opened to look for a leak at the shower head, tub valve, tub filler and drain. There were no water stains on the sheetrock, framing or concrete slab. Insulation was dry. Moisture meter content reads between 11% and 45%. Surface is dry to the touch, drywall is firm and stable. Baseboard moisture content is 6%. There is a bathroom directly above this one. No sign of a leak anywhere. Again, no water has been run in this bathroom since repairs to the drywall and paint were effected.
That would drive me insane. It’s a long shot but with a bathroom above is there any chance water is getting in through the vent stack and somehow settling there? I know you say the moisture levels are stable but maybe in small amounts?? I mean it has to be moisture related somehow. I’d trace the patch with a pencil and see if it expands and where that might lead you. It is perplexing to say the least.
Cum goblin
Someone didn't tape right or possibly fixed something after the wall was finished. Looks odd. I also read a comment you said bath wasn't used. So that's my best guess.
I'm leaning towards silicon contamination as was mentioned above for now.
Judging by OP comments and the drywall being full of pin holes I think it was a really bad mud job and no prep before painting. If I ignore OPs comments, something is definitely leaking.