Shower reno - removing cast iron drain from concrete

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Hi everyone,

I have a basement bathroom with an old tile shower that had been improperly installed and was moldy and falling apart. I tore it out to the studs 2 years ago and just haven't gotten around to redoing it due to the drain situation. The house was build in 1962, so I have some galvanized drain pipes and this shower appears to have a brass drain with a rusty old pipe that I'd like to replace. You can see I tried chipping away with a chisel and hammer and was getting nowhere fast. I want to rent a 20 lb demo hammer from home depot and try and chip away the concrete and make a 12" hole around the drain center. I'm concerned that I might damage the pipe beyond where it elbows 18" below the surface. I'd like to use a kerdi drain and system for reference.

Pictures of shower and drain: https://imgur.com/a/SnoUb

Questions I have:

1.) For removing and replacing the drain, is a demo hammer the way to go? I've never removed concrete, so is this something I should hire a plumber for, or is it simple enough for a DIY'er to do with a hammer and then Fernco couple PVC to the galvanized pipe? Do I need to scope the drain to see how bad the corrosion is downstream? I've poured water into the trap and plugged it for 2 years with a towel, and it appears to still have water at the bottom so hopefully it isn't leaking. I haven't tested the flow rate to see how quickly it drains, though. The main stack vent/drain is about 5 feet away. The drain goes into the concrete floor along that curb, which is a wall between this bathroom and the adjacent utility room. I'd think replacing the drain to the main stack would involve some serious demo, so I'd like to replace the drain correctly without making this a huge undertaking for myself.

2.) I'm replacing the manifold with a Hansgrohe iBox. I'm still using a standard single shower head, so it should be straightforward. Is this a DIY job or should I hire a plumber to install? I've only sweated copper pipes once before, but I could learn and would think any issues would be apparent right away.

3.) I'm guessing there isn't a liner underneath the concrete pan, so should I just raise the drain and use a preformed shower pan?

Thanks in advance.

 

[Michael Stoecker]

Hello, Please contact Hansgrohe at 800-334-0455 for options for your shower. I would recommend hiring a plumber though for the installation.

 

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[Tanner]

Updated the initial post with pics. I haven't tried removing the drain yet, but was wondering about the venting situation. The concrete curb opposite the shower threshold is where the main vent/drain line goes below the concrete and where the large vent is on my roof. There's a sink and toilet on the other side of the shower valve wall. It's about 4 ft between the shower drain and main stack. I poured water into the drain at about 8 gallons/min and it had no issues draining, so I would hope it should drain just fine for a standard shower head. My main concern is if the pipe is corroded through between the shower drain and where it enters the main line. Is this a legitimate concern, and would I be able to tell just replacing the trap around the shower pan? I'd like to avoid trying to replace the shower drain all the way to the vent since I'd have to demo half my bathroom just to get to it.

 

[Cacher_Chick]

I saw-cut a square of concrete around the drain and then finish it with a sledgehammer. If the pipe is in good enough condition to be worth saving, some pounding around the drain is not going to hurt the pipe. If you can dig down to the trap, you can replace it and the riser.