I have added new drywall to a single wall in my living room. The ceiling and right-hand wall were previously textured and painted (and there is some mortar from the wall I replaced, which was covered in faux rock). I have been trying to smooth the texture and paint by multiple means, but the paint is very tough. I have tried 60 grit sandpaper and sponge, a rotary sander, and a paint scraper, but progress is limited. I am afraid to try paint thinner or stripper for fear of destroying the drywall underneath.
I have it to a certain smoothness now, but I am sure the tape will not be smooth if I apply it. I was thinking I could put a smooth, thin layer of mud on the wall with the 12" knife and, after the mud dries, apply the tape on top as if it were fresh drywall. Would there be any issues with this?
Hi, broadbear. You need to remove all the mortar, unless you later put a very heavy texture on that area. A power sander and 60 grit paper would remove paint and texture very fast, unless you're talking about the grout. If so, I would use a wide-bladed chisel to remove it. The chisel has 2 sides to the blade, try each for best performance.
Where the tape goes has to be sanded below the rest, so when you add 3 coats of compound there, it won't be much higher than around it.