Is it OK to apply thinset to cured thinset?
I’m tiling my shower walls and managed to finish about 1/2 a wall. I scraped off the thinset where it wasn’t covered by any tile. However, there is a smooth surface now where the scraped thinset was.
I’m pretty sure that I can simply apply new thinset over the old thinset without any problems. Just want to confirm.
Should I rough up the old thinset at all?
Thanks in advance.