Paint basement floor with white efflorescence, year of construction 1960

Hi Jochen,

you really gave this some proper thought – many just paint over it and then wonder about blisters or mold. If the cellar doesn’t have a continuous floor slab, then the moisture from below simply can’t be ignored. Anything that is vapor-tight will eventually give you problems, no matter what the label says.

These "diffusion-open" epoxy resins are usually only more diffusion-open than the dense variants, but not truly breathable layers in the real sense. That means with an old cellar without a barrier, you still risk moisture buildup. I’m surprised your neighbors are satisfied with it – have you seen how their floor looks today or just heard that "everything is fine"?

A mineral, silicate-based solution would be much more sensible here. Maybe a bit more plain visually, but technically sound. If you do it properly, you’ll have peace of mind and no material that flakes off after six months again. Or do you want to use the cellar more intensively, for example as a workshop with rolling loads? That would be decisive for the choice.

Have a nice evening

No. No workshop. We just walk there... And one room is a laundry room. I only know silicate paint from the wall, what is that for the floor?

Jochen, if you already know silicate, you are not that far off from the right thing. There are indeed mineral floor coatings that work on a water glass basis – basically a kind of "silicification" of the screed. The surface remains vapor-permeable but becomes harder and more resistant to dust and abrasion. Visually, it is not a high-gloss finish, rather a matte, technical look that appears very clean.

You just must not expect that stuff to mask cracks or swallow small unevenness; it remains honest – just as the floor is. And that is probably better than some plastic layer that ultimately only preserves the moisture for you.

Have you actually checked how strong the moisture under the can really is? That is, whether it is pressing up from below or if only condensation arises due to the temperature difference? That would be the crucial question before you apply anything at all.

Thank you. So I am pretty sure that it comes from below. On the one hand, of course, because of the age of the cellar. On the other hand, because at 30% humidity at 18 to 20 degrees, I can't imagine that the cellar floor has the dew point, it's far away.

What would such a silicate floor paint be? Because when I search for floor paint I never find anything. It's always paint for the walls. Or do you simply use wall paint for the floor?
Regards Jochen