Next year (tax return) Im going to redo my bathroom and get a shower wrap to go over my tub & tile walls. I've got a problem I have to fix before then. Ive had the house a year now & there was loose grout in the tiles in the shower. I've patched it with caulk for now but theres a soft spot below the soap holder and theres loose tile. I know I have to replace part of the wall. My questions are; since its soft Im assuming someone used drywall instead of backerboard. Which should I use to patch the wall? should I use grout as the joint sealer instead of spackle? Can I reuse the tiles and if so, how do I clean the backs off if theres grout stuck to it ...wire brush? What tools will I need? What can I use to remove old grout between the other tiles that arent loose yet so I can regrout them before they get worse? Thanks for the help.