What is this yellow goo running down my walls?

[Dylan T]

Hi all - I've recently had a bathroom makeover and painted the walls white with kitchen bathroom dulux easycare. I painted over existing light grey walls that had no problems. Since painting after a shower a yellow goo drips down the walls and you can see it collecting on the caulk of the tile trim. All walls are doing it - there doesn't seem to be an area worse than another. If I wipe it off the yellow stuff is transparent and slightly mucusy; kind of like if you leave a tin of paint for ages in the shed and it separates and you're left with a clear-ish layer on top.

But the tin was new, well away from expiry, and i got a large one that i used in the kitchen and utility room all which are fine. I've also painted so many rooms in many houses before - i'm open to user error but I can't think what I haven't done a million times before.

I've researched online and the two main things that seem to come back are cigarette smoke which I can rule out as no one here smokes and the room was previously taken back to bare plaster. And the other is that its a settling in of the paint but it's been 4 months now and it's still happening; making a bit less but still enough.

Ideas really appreciated!

 

[Odds]

Does the room collect a lot of condensation overnight?

 

[Dylan T]

Does the room collect a lot of condensation overnight?

It can get quite steamy after a shower; the room has proper extraction via van through pipe into a fitted roof vent in loft, but shouldn't be other forms of condensation coming in at night. I did have a thought that there was dust in the extraction pipe that was somehow mixing with the steam, coming back down into the steam but i don't think that makes sense, and wouldnt form on the walls that quickly, and I think i'd also see actual dirty drips coming from the pipe onto the floor which i don't.

 

[Odds]

Run your hands over the wall to see if they're damp, otherwise look into alternative solutions.

 

[Dylan T]

Run your hands over the wall to see if they're damp, otherwise look into alternative solutions.

They're not damp, just condensation after a shower.

 

[freddiemercurystwin]

Is it only on that junction or on the walls in general too?

 

[Wayners]

It's the mastic that's deteriorating and being affected by moisture.
Run some low tack masking tape down wall and clean off plastic with cif.
If that don't work then you can use uPVC as solvent cleaner.

 

[Dylan T]

It's the mastic that's deteriorating and being affected by moisture.
Run some low tack masking tape down wall and clean off plastic with cif.
If that don't work then you can use uPVC as solvent cleaner.

I wish this was the case but unfortunately it’s running down the walls above the caulk, it’s just that it’s more visible here for a photo as you can see it collecting. The caulk was new at point of painting anyway

 

[Dylan T]

Is it only on that junction or on the walls in general too?

Entire room