I have an apartment in Turkey, there is one wall that takes a hammering over
the wet winter months, the wall is currently painted externally and
internally and is not on the ground floor, When I go out in spring there is
a little `dampness` on the inside of that wall, normal for turkish builds
and easily sorted with a quick scrape and a new coat of paint.
However I would like to at least improve the situation and even better if I
could solve it by trying to coat the wall with something to seal it.

Any ideas?

thanks.