I am removing a fiberglass tub/shower and will replace with a hot mop shower pan with appropriate double drain. The bathroom sets on the first floor slab, with the drain about 8 inches from the wall. I want to move the drain to the center. If I break the concrete and move the drain to the center, how do I fasten the drain to the slab? Do I give myself enough room with an access hole to run my drain line, attach the drain to the pvc, then fill the hole with concrete, and attach the drain with concrete screws? Any help will be appreciated. stairman2001

My name is Justin I am a fourth generation shower pan hot-mopper and the answer to your question. Bust the concrete out from its present location and continue to the location you desire. Take your piping and combine with existing plumbing to the new location. If I were to come in to mop this is what I would like to see ( for positioning of drain ) is the bottom drain flange top, flush with the concrete that you are about to pour. NOTE: never screw screws through a drain even on a wood subfloor. Your concrete poured around the drain will be perfect to hold it in place and it will not move. I hope that this thread has helped you with your question or questions.

I am not sure why you believe a double drain is appropriate or necessary, it is not. You might consider reviewing a Swanstone retro 3260 shower pan. They are designed to replace a tub with a shower and use the existing drain trap. Swanstone Retrofit Shower Floor Left Drain - Home Improvement - Compare Prices, Reviews and Buy at NexTag - Price - Review

The bottom portion of your CI drain has flange with 3 screws. As you tighten the screws, it squeezes the seal against the pipe making positive seal.

Some drains have ABS bottom and CI top. You just glue the bottom directly to your ABS / PVC trap riser, hot mop over it, and set upper half into hot hot-mop.

Your drain MUST have weep holes. Don't attempt to install drain w/o them or you will be redoing your new shower pan again. Weep holes drain condensation that occurs between the concrete and hot mop when hot water hits cold (concrete and tile) shower floor. When you install upper portion of the drain (over hot mop), than the height of the drain will give you finished height of your pan floor.

Some drains have adjustable top portion that screws in and out. But still, it is a two-part drain...

Ballengerb1: Yes, double drain is necessary for hot mop. ( " Double Drain" - meaning drain that can be split into two halves )

I mistook the terminolgy and thought he meant two separate drain pipes. Thanks for the explanation. I do so many Swanston 3260s that I forgot how to do a pan from scratch. For those who want a custom pan I offer this link, Ryan seems to know what's up with building a pan. How to Build a Shower Pan