But the pipe and drain fitting need to be taken apart and replaced if necessary in order to insure that a leak won't undo your efforts at reinforcing the floor. Mold won't grow without moisture.

Ideally, youll already have a drain roughed in, with the pipe sticking a few inches above the floor. Otherwise, you must break through the concrete to run a new line for a shower stall installation.

The house I grew up in had floor drains in the garage and they were wonderful. ... Downstream from the box drains I installed a self-made P-trap using 90-degree fittings.