1. Observe and protect
Photograph the issue, prevent further damage where you safely can, and write down when you first noticed it.
2. Evaluate the house and site
None of it shows once the tile goes up: where the drain sits, what the framing behind it looks like, how the waterproofing was detailed at the transitions, whether the fan can actually clear the room, and how workers can get in and out. In an older Elgin Historic District or Spring/Douglas home, that evaluation should include when the bathroom itself was added relative to the house's 1886–1920 construction.
3. Define a written scope
Get specific about preparation, protection, materials, access, required permits, testing, cleanup, restoration, and exclusions in writing.
4. Compare providers
Confirm each provider's credentials and compare how they justify their approach, not only what they charge.
5. Inspect closeout
Confirm testing, a clean job site, complete documentation, warranty paperwork, and what maintenance falls to you going forward.