Hello! I was wondering if anyone has experience how to convert the sandpaper style wall finish to a smooth finish?
Is it generally just sanding down till smooth and adding a new layer of finish?
Does anyone know the names of the finish type in German? I don’t even know how to call it in English 
Depends how hard it is. I mean yes, but if it’s a large surface it could be a lot of work, and if it’s very hard you may need something more than a basic sanding machine.
Alternative is to just knock off the worst and just cover it over with more Crepi
Putze is a very general term, I think. In French it’s either crépi or enduite, where the latter is again a generic term for what we’d call filler in the UK. Here’s the German version of Hornbach’s offerings:
In English we (that it, me) just call it crépi, as I’ve never found a UK equivalent term. Back in the 1970 when it was popular there was a product called Artex, so it may be that the word is still in use there.
Thank you! We’d like to potentially change over all the walls to a smooth finish, so perhaps we’ll need a machine. I’ll ask around at the hardware store too. Or we’ll hire someone… But where’s the fun in that!
When I’ve tackled this sort of thing I’ve never been intending to get a completely flat smooth finish, but a textured effect, no jagged bits but some some texture, sometimes deliberately with an pattern effect in mind. There are loads of tutorials on the hornbach site it may be worth looking at.
But for completely flat smooth like a modern new plastered wall you’ll need to start with a flat surface, and IME you’ll also need a professional plasterer. That’s just me knowing my limits though YMMV.
Keep in mind that Switzerland used asbestos long after it was banned elsewhere (I think it wasn’t fully banned until 1994 for home use)… Including in wall textures. So be a little cautious around sanding/chipping it off.
Sometimes it’s much easier to just grab some drywall panels and glue them over it. Then you plaster the joints (a bit of joint tape helps), and smooth/sand. Paint over, and bob’s your uncle.
EDIT: Some pictures of asbestos-based wall/ceiling textures: Asbestos Textured Coating Gallery - Acorn Analytical Services
Our French house had a chimney breast covered with this type of thing, and for that reason (the possible asbestos) it became the first time that I’d done the job being asked about, that time simply covering completely with crépi and painting over it.
Would have cost quite a bit to get specialists in to even check it out, then a lot more to remove it safely, but completely covering it over is considered a safe approach, so there’s no actual need to remove it.
We had a house in Essex, the previous owners had decorated with a bark effect Artex everywhere including the ceilings. It had to be steamed of then we had to get a plasterer to put a layer of skim over it so we could redecorate. I have the stipple effect stuff in my apartment here and absolutely hate it. You can’t clean marks off it for a start and it’s like something from the 70s, despite the fact this flat was a new build when we moved in 6 years ago.
That’s because Eternit is a CH company.
You could also try wallpaper that is thick enough to hide the wall texture.
I agree about the asbestos danger so avoid trying to remove the finish
Edit: You can also buy rolls of styrofoam (styropor) which will give you a flat finish as a basis for decorating.
Note both these methods will not hide imperfections in the walls which texture does hide.