I am in the process of having a new bathroom fit. The plumber has left for the day and so i have just been to see how it looks. The tiles we have chosen are quite big and I can see into the gap between the tile and the wall that he hasnt put adhesive all over the wall he has put blobs in each corner and the middle. I am concerned that the only thing keeping water from seeping in and running down the gap between the wall and the tile will be grout. is this acceptable?