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.
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.