I freaked out about the waterlogged boards I couldn't remove and phoned a contractor for a price to remove everything, repair floor and walls if necessary, install a fibreglass shower and a give a time frame for completion. His wife took the message and promised a call back that evening. It's been about a week, no call back.   

My son was in town on the weekend. He removed the yucky board for me and also removed most of the caulking where floor walls meet.

I haven't tried the Dremel grout removal tool yet because I discovered that all the tiles on the lower part of the walls are loose. The 25 year old adhesive had dried out and let go. The grout was holding the tiles together in sheets. As soon as I released one tile, many others fell off with it. Most of the grout crumbled off the tiles in the process.

All (I hope) loose tiles and accompanying grout have been removed from the bottom four feet all the way around. Many tiles broke. I'm scraping the old glue off the walls in hopes of leaving a clean, dry, somewhat rough, surface for the mortar to bond to. My husband has begun cleaning old glue and bits of grout from the intact tiles. When I'm satisfied that the walls are sound, I'll work on cleaning tiles too. There is rather a lot of them.

There is one place where the wall is bulging out. I'll see if I can figure out how to use a wood plane to make it flush with the rest of the wall. If that doesn't work I'll have to try to cut out that piece and replace it.   I hope my efforts won't cause more tiles to fall off. I only have about a week to get this done.

Next, I'll try to remove the old one inch square floor tiles. I wonder what nasty surprises lurk there?

rags