I am sure this is not the first time this has been asked, but search did not help. We have tiled our shower, but when applying grout, it is not "out" far enough? If that is the way to explain it. Can we simply add another layer so to speak? It is dry and we only noticed when cleaning up.

Peter & Pam

Most joints will be lower than the top surface of the tile depending on the shape of the tile edges. Can you post a photo of the grout joint?
Adding a very thin layer would not last. You will need to remove about 2/3 rd's of the grout depth.