ᐅ Removing Soot Stains from an Old Chimney

Dear members,

About two years ago, I bought a nice house in Bavaria and have been doing as much as possible myself. So far, everything has gone well, whether with contacts, contractors, or DIY. Now there is one problem that I do not yet know how to solve and I need advice/help from you.

We have completely finished the interior work, removed everything, redone and replastered it all using good plaster that protects against mold and similar issues. However, in one room—and from the other side, also in the adjacent room—soot stains have formed from an old chimney that is no longer in use. The question is, how can I cover these stains? I have very good paint from our painter that covers evenly, even on dark plaster—real professional painter’s paint, not just a regular brand. The problem is, the yellow-red staining keeps showing through.

Despite advice not to, I bought some "anti-nicotine and soot paint" from Obi. You can forget about that. For one, it is not white and it does not cover the soot stains as described. Our painter revealed a small trick: simply stick aluminum foil on and then attach panels or wallpaper on top of that. I can imagine doing that on the ceiling, as panels will be installed there anyway. But on the walls, we want to use paint only. In the ground floor, we either have stretch ceilings or wood chip wallpaper, and the walls are painted white. Now the upper floor is next to finish, and that is where we have this problem. Does anyone know a trick or a solution?

Thank you very much for your replies.

I would try treating that with a surfactant-based plastic cleaner (usually in spray bottles). With or without ammonium hydroxide (respiratory mask recommended!). Possibly follow up with hydrogen peroxide.

In the right picture, it also looks like it might be slightly scorched?!?

Instead of making such a fuss, I would quickly fix it with drywall.