Any idea what’s causing this bubbling ?

[Fmill]

A few sporadic bubbling patches have appeared on the wall- see pictures.
I sanded some other areas where it occurred back, and then repainted- but it’s come back.

Now re-painting the wall a new colour and need to deal with these.

Any idea what best approach would be?

Thinking, sand, fill, bullseye, repaint?

Thanks in advance

 

[foxhole]

Looks like effervescence do you have damp on that wall? Is it an external wall or a chimney?

 

[Fmill]

Thanks. No signs of damp, but it is an external wall yes.

 

[Leftum]

A few sporadic bubbling patches have appeared on the wall- see pictures.
I sanded some other areas where it occurred back, and then repainted- but it’s come back.

Now re-painting the wall a new colour and need to deal with these.

Any idea what best approach would be?

Thinking, sand, fill, bullseye, repaint?

Thanks in advance

I had something similar on a wall I painted yesterday. I painted over it and it grew in size. I scrapped it back and left it to dry.

Mine is an external wall and the gutter was blocked- but it isn’t now. The wall seems bone dry. I’ll do as above and hopefully it won’t peel off.

 

[opps]

Looks like effervescence do you have damp on that wall? Is it an external wall or a chimney?

Agreed, the salts in the plaster have pushed to the surface.

BTW, it is efflorescence. Effervescence the release of gasses (bubbles) in liquid. That said, both result in bubbles.

 

[foxhole]

Agreed, the salts in the plaster have pushed to the surface.

BTW, it is efflorescence. Effervescence the release of gasses (bubbles) in liquid. That said, both result in bubbles.

Auto correct maybe, wrote it 4 times then gave up .