great point about leaks and floods...
I have my Ilford MC 500 up on a small stepstool (and the spare as well, actually it sits on one of those flower pot bases with rolling casters - these things are QUITE heavy) so that in case of flooding, my electronics aren't sitting on the ground.
Concrete floor and linoleum,have no need for anyting more.
(BTW tired to have all the colour in the darkroom as close as possible to the darkroom light such that reflected light from various sources would reflect fogging light as little as possible, ans still give light!)
Mine is plain old concrete. It works well, but it's hard on the back. I could put down some interlocking resilient pads in the heavy work area, and I may. But those can be hard to keep clean. Linoleum sounds like an excellent idea.
Ceramic tile and a bar stool. It is just the right height for the counter top and sink. For the enlarger I stand.