sticky stain keeps coming through

hi, we have recently painted our place. there is a spot on one gyprock/plaster wall that is vexing us completely. Its a stain. its always been there. well, since we bough the place anyway. so, 6 years. its a little sticky to touch. my wife has now painted over it 7 times; mostly this last week. sure enough, the stain comes through the paint by the next morning. I have inspected the plaster from the back through the hole cut for a light switch in the neighbouring room. clean as a whistle and nothing stuck inside the wall. leaves me thinking that whatever it is, its on the surface.

we have tried sugar soap and other cleaners to no avail.

so, what next?
Attachment 536965

If it's been painted that many times, cleaning it with anything won't help because it's not dirty. Whatever it is has a colour and reacts with, I assume, the acrylic paint, which is what will be sticky. Have you sealed it with a stain blocker paint such as Zinsser Bin shellac stain blocker?

Quote:

---

Originally Posted by mic-d

If it's been painted that many times, cleaning it with anything won't help because it's not dirty. Whatever it is has a colour and reacts with, I assume, the acrylic paint, which is what will be sticky. Have you sealed it with a stain blocker paint such as Zinsser Bin shellac stain blocker?

---

no. we haven't. was just reading about zinsser stain blocker. will give that a try. is it something that can just be painted over the stain, left to dry, and then painted with regular paint? should we use the stain blocker to give extra coverage around the stain to stop it spreading out (not that it has, i don't think)?.

for clarity, we attempted to clean it before painting over it the first time (years ago) and then again at the start of last week prior to painting again.

Quote:

---

Originally Posted by ajm

no. we haven't. was just reading about zinsser stain blocker. will give that a try. is it something that can just be painted over the stain, left to dry, and then painted with regular paint? should we use the stain blocker to give extra coverage around the stain to stop it spreading out (not that it has, i don't think)?.

for clarity, we attempted to clean it before painting over it the first time (years ago) and then again at the start of last week prior to painting again.

---

Hi, yes paint it on with some extra coverage beyond the stain and paint over as regular undercoat.

thanks. will grab some on the way home.

Quote:

---

Originally Posted by ajm

thanks. will grab some on the way home.

---

let us know how it goes