I think that hj is right. Now that is a HUGE gap! I'm pretty sure that water would be a problem there. I mean a BIG problem, not a small one. Maybe as big as a dinosaur. How tall are they? Maybe bigger than a 10 story building. Maybe faster than a speeding bullet. In other words, maybe that is just TOO big. Maybe you can cut a bit higher up the wall and put in some good backer board. You could to up two, mayber three rows up. Then tile everything back up again. Mad Plumber

: That is too large a gap for a properly installed tub and/or tile job. It is also too large to fill and make it look decent and last for a long time.

: : I'm not sure how to fill in a gap (about 1"-1 1/2") between tub and tile before caulking. I have used caulk only, but it takes an extremely long time to dry, and eventually cracks form. It also seems to be hollow behind this gap. Any advice greatly appreciated.
: : Thank you.