Why is this damp ring keep reappearing!?

[ax222s]

Hi all,

2 years ago I had a salt lamp on this alcove shelf. It got humid and the salt lamp 'sweated' and formed a pool on the shelf. I removed the salt lamp, mopped-away surface water and put dehumidifier on for 48 hours. The mark disappeared. Its been fine over summer, but now its getting colder its reappeared again!! It cant be damp can it? Why is it reppearing? That mark was never there before the salt lamp sweated. Very odd.

I dont know if this has got anything to do with it, but its a cob wall with lime paint.

Thanks

 

[ax222s]

Reattached a high contrast image that better shows the mark

 

[blup]

Salt in walls is a source of damp, so its likely that the crystals have been absorbed in the wall and like other forms of damp comes to the surface when temperature drops. Its a little ironic that a product with health benefits has caused damp.

Blup

 

[ax222s]

Salt in walls is a source of damp, so its likely that the crystals have been absorbed in the wall and like other forms of damp comes to the surface when temperature drops. Its a little ironic that a product with health benefits has caused damp.

Blup

Ah I see! So what do you think I could do? Brush the salt away? Keep brushing it away as it comes to the surface? Overpaint it?

 

[blup]

Two options, remove the plaster and leave it for a year or so to dry out then restore, or apply something like zinsser bin which will effectively "tank" the area and prevent the damp coming through.

Blup