I need guidance regarding how to repair the gap between the water line tile and the pool deck. The picture below is an illustration of how the pool deck was poured when the pool was constructed. The pool deck was poured over the top of the bond beam to create the edge of the pool and the expansion joints were installed in the deck perpendicular to the pool wall. I am not sure when the waterline tiles were installed, however the tile grout has chipped out in areas and in other areas a gap is forming between the top of the tile and the bottom of the pool deck. [attachment=0:3r80vzyq]Pool Schematic.jpg[/attachment:3r80vzyq]
Question 1: Does a joint need to be cut parallel to the pool wall about 1-1.5 feet back to create a coping allowing the pool deck to move independently without effecting the section touching the top of the pool. If so what kind of caulk should be placed in this new joint?
Question 2: In the gap between the top of the tile and the bottom of the pool deck I would like to ideally replace with grout. Can new grout be applied to the joint or is a more flexible sealant necessary? Does the ideal grouting material depend on whether or not a new joint is cut in the deck as shown?
I sincerely appreciate in advance any advice.