I moved to an old house south of Germany. For various reasons (mold, ugly looking, etc.) want to paint the walls from scratch by scrapping all the wallpaper and paint. I started from one room, I scraped all the wallpaper and old paint by using a spatula. I will sand all the wall surfaces to remove all the existing residue of wallpaper and paint. (glue etc.)
In the end, I will have the following surface as a starting point:
It is a thick plaster layer (like concrete) over bricks.
I want a nice finish and a solid & durable coating against the mold forming so I don't have to build my walls every year. (humidity is relatively high)
I read a lot on the internet about how to build a good wall finish. But still, I don't have a concrete idea of how should i prime, plaster, and paint the walls in the right way.
There are a couple of questions in my mind:
Do I need to prime the raw surface before plastering? If so, which material should I use and how to apply it? There are articles suggesting applying PVA before the plaster to control the moisture from moving from inside of the wall to the plaster/paint surface.
Is sanding over the plaster a bad idea? I read some comments about the plaster should not be sanded at all. I was thinking to sand the plaster after it dries to make it perfectly flat because I am not very experienced in plastering and most likely will end up with an uneven wall surface.