Are these encrustations due to damp?

[campariman]

From the photos can anyone please diagnose what is causing these unsightly raised marks on my lower walls? They are basement walls. I normally sand them down and repaint but after a few months they reappear. Also, on the corner and another just above the skirting I did repairs a short while ago with Polyfilla only for encrustations to appear all around the borders of the filler. Polyfilla dried a funny brown colour and it seems to be seeping through now. Elsewhere on the walls the encrustations appear as small hard raised dots. The walls do not feel damp but could this be the underlying cause nonetheless? Is there anything I can do that is not too brutal, something that can hold it back for a few years at least until the next decorating round? Any advice gratefully received.[img]





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[welsh brickie]

yes its damp,the white fluffy stuff is effloresance,It will keep on reoccuring
try painting the wall with a pva solution,it may help but its no guarentee,to completely eradicate it the plaster needs to be removed and the walls tanked

[campariman]

Hi and thanks for the reply. There is nothing fluffy about these nasty beggars; they quite hard and crusty and I have been known to take a chisel to them. Presumably effloresance can take this form as well? In which case I could certainly try a pva solution though I also have some Polycell One Coat Damp Seal.

I notice many have viewed the question but I would be glad for the opinions of others experienced in these matters.