I have three questions for anyone who can help. PLEASE SOMEONE HELP ME! What's happened here is that the tiles above the tiles that you see have fallen off due to erosion, growth of roots, etc.
(1) How do I fill this gap, which is behind tiles that fell off? Which product (please be very specific) do I use to fill this gap?
(2) What type of tile glue would I use to attach the tiles to the wall here? (please be very specific with the product name) I know that the glue has to be different to the standard indoor floor tiles for a kitchen.
(3) What type of grout do I use for tiles like this? (it will be submerged under water)
Someone please help me! I'm in desperate need of advice.