Step A is getting the old tile out. This is youngest son, Jonathan, going at it
This is the original tile that came with the house in 1962. The insulation batts are fiberglass and original too. They are in fair shape considering their age and the water that has leaked onto them over the years.
Water leaking behind the tile has done a number on the studs. We flushed out a big carpenter ant's nest when we pulled out the last piece of soggy dry wall. Concrete board or blue board hadn't been inventing in 1962, the tile was laid on plain old paper covered drywall.
When the ant's were discovered, I handed Jon a can of bug bomb. "But this says for flying insects" he objected. "Give it to 'em anyhow."
And the ants curled up and died in a very satisfactory fashion.
Whacking old tile.