Hi, I have removed wallpaper in the basement, but when I tore down the wallpaper, there are remnants of glue? left. I was planning to paint with silicate and wonder if it has to be removed first, it is about 2mm thick.
If it's a dry wall without the risk of incoming moisture, there's no problem with glue remaining. However, it looks more like putty, which is often cellulose-bound, so mold can grow quickly on it if it gets wet.
I had the same on some of my walls. I used a Japanese spatula that you can angle under and break/knock in and remove quite large flakes, and then a regular 80 mm wide spatula that I tapped with a hammer at the end to remove what was stuck harder.
I also tried sanding, chiseling, and sawing with various machines, but it damaged the aerated concrete behind way too much (or created an awful lot of dust).
