Leak under shower/toilet slab area

[mbauer]

I'm in the process of replacing an 80's shower stall and had to break up the slab to replace the clamp drain. The drain was totally encased in concrete about 15 inches deep. This is a shower stall on the outer wall so it was in the footing around the house. Oh how I wish I had pier and beam. Anyhow, when we were demoing, the hammer went through the ptrap so we had to keep going. An hour later we revealed the full p-trap and some of the pvc going towards the stack. It took a LOT of work to get this clear. Two issues came out of this.

First off, the ptrap was totally clogged and I noticed that the pvc was sloping towards the trap. I was willing to take a chance on the negative slope since this shower was in service for over 20 years and put the trap and drain back in. But, after the holidays I started back into the project and realized the dirt was muddy around the drain. Yesterday I rented a hammer and demoed out enough to try and get my hand back towards the main stack off of the toilet. The area is muddy like the pack you would use for a showerpan. There seems to be a pretty decent crack or leak under there. It was dry when I initially demoed everything so I know I introduced it when we were demoing it the first time.

I'm going to have to go all the way back to the toilet drain and try to fix it. I'm looking for advice on what to expect. This seems like a doable DIY project. I've got a half dozen projects under my belt, but I've never messed with replacing underground drainage of this size.

Any suggestions on demoing the area around the toilet, getting underneath it all and figuring out what happened? You can see the trench leading back towards the main stack. I was just going to demo everything to the left of the toilet and a little bit on the right. Any explanation of what I am up against, given this is in any way typical?

 

[Terry]

If using a hammer drill, make sure you are impacting to the side to prevent "spearing" the pipe.
All I can say is be very carefull around the pipe. All you need is a good clean place to cut and couple to.

 

[Sponsor]

 

[ShowerDude]

keep digging get rid of as much cast as you can

by now youve probobly tore more slab up and chased that back to your main stack?

Go ahead And lower your new drain flange to the slab if your trap depth allows.



i like your effort to add blocking at sole plate. That tells me you are doing youre homework on how to frame for a shower build.

 

[mbauer]

Thanks for noticing the blocking. I've read, re-read and read a few more times using tutorials and books. I would really like to build this shower once and ensure that it lasts for as long as possible. The shower from 85 had a liner and lots of staples in all of the corner at the base of the floor up through the top of the liner. They stapled at each 2x4 as well. I'm actually surprised that I didn't have a bigger mess behind the walls.

The story of the wet sand unfolded as I started breaking up the floor. When I removed the carpet I could see that the concrete was patched. This house had an upstairs bath added in 97. They ran a new drain down from the attic next to the existing vent pipe and tied it into the existing toilet. They used a fernco connector to connect old to new. That appears to be where my leak is. There are roots in this area and I am betting this has been leaking for some time. It's nice to know it wasn't my initial demolition that rattled something loose. I'm also feeling pretty lucky to have discovered it at all.

The left is the waste and the right is coming down from the upstairs bath. The vent pipe goes up on the left side. The shower taps in right to the left of the toilet at the vent pipe.

Any suggestions on how to fix this correctly? Also, can someone explain why they would have put a cleanout under the slab?

Thanks

 

[Terry]

Is there a pipe for the toilet vent. It looks like an empty hub there.

The rubber fitting is not one I would have used.
The cleanout under a slab is no help.

 

[mbauer]

Here's a pic of the vent pipe attached to the toilet. To the left is the shower drain.

I'm thinking that there isn't a way for me to put PVC back without major reconstruction.