Avoiding slab shower base leakage

[Howard M Emerson]

Hello all,
I'm renovating a slab bathroom that previously had a 1-piece shower wall, base & ceiling. The old base had leaked, and I'm certain the culprit was the matching flange that held the strainer/grill. It was cracked across the top where it fit into the old base recess area. The majority of the water successfully made it down the drain, but over 20 years of a little water at a time adds up, right? I believe the mother/daughter apartment was built in 1985, so it's had some usage.

I'm now going to be placing a new Dreamline shower base using a brass Oatey 2" drain. I'll be using a new piece of 2" pipe. I even made a point of inserting the old piece of 2" into the rubber compression doughnut that is firmly embedded in the cast iron hub, and then I attached a hose to it, running the water for a few minutes to see if any water showed up AROUND where the PVC 2" was inserted.

I saw nothing, and the flow to the cesspool (viewed via the vent stack out back) was fine. So my plan is to set my base in mortar as instructed (I've done several on wood frame, prior) and after it is set, I'll do a plug test to make sure the drain/base joint is tight. I should even be able to view that area from one end because the wall is not sheet rocked on the opposite side. I'll set the mortar between 2 sheets of 6mil plastic in the event that something has to change.

So.......my question: Should I lather up the 2" PVC with some Duck Butter before inserting, or what? Is there a way of making the old rubber/new pipe fit a little tigher, of just leave well enough alone? I'm thinking that the old rubber is in for the long haul (ie: if it ain't broke, etc) and here's a picture

Again, thank you for your experienced opinions!

Best,
Howard Emerson

 

[Jeff H Young]

You expect enough space under the shower drain to be able to have pipe slip into the donut? Dran location identical? The vast majority Ive done drain wasent in center but they were mostly one piece enclosure. Perhaps the pans are centered. I dont pay attention because generally i almost always replace the p trap and make sure I have a location.
Id want a new rubber and yes on the duck butter

 

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[Howard M Emerson]

You expect enough space under the shower drain to be able to have pipe slip into the donut? Dran location identical? The vast majority Ive done drain wasent in center but they were mostly one piece enclosure. Perhaps the pans are centered. I dont pay attention because generally i almost always replace the p trap and make sure I have a location.
Id want a new rubber and yes on the duck butter

Hi Jeff,
The pipe already slips into the doughnut. I centered the new base with the existing pipe precisely where it needs to be. Breaking up a concrete floor is not an option, so I made concessions based on the existing drain location. Here's a couple of pictures showing the base exactly where it needs to be, with the pipe inserted and without:

As I said earlier: When I put a garden hose at the top of the pipe and ran water for several minutes there was NO water on the outside of the pipe where it enters the doughnut. I just want to give myself even more confidence about its integrity if at all possible. I know that a new doughnut would give me that, but extracting a 30+ year old rubber doughnut, and THEN expecting to get a new one INSERTED into old cast iron is a crap shoot.....so if the Duck Butter would be a plus, great! I have a container of it, but any other ideas are welcome.

Regards,
Howard Emerson

 

[Jeff H Young]

I guess as long as it fits tight in the donut you are good . Id feel beter replacing it .
So I guess the outside of the hub and donut are flush with concrete and enough space for shower drain.
It looks good Howard I dont see any problem

 

[Howard M Emerson]

I guess as long as it fits tight in the donut you are good . Id feel beter replacing it .
So I guess the outside of the hub and donut are flush with concrete and enough space for shower drain.
It looks good Howard I dont see any problem

Hello Jeff,
No, it's no where near flush with the concrete. It's about 2.5" below the surface, which I think is in my favor. I had 'toyed' with the idea of off-setting the drain to maximize my layout, but it would have required bending or casting my own PVC pipe. I feel very confident with the brass Oatey drain that is tightened around the pipe from above. Any offset they make is all plastic, and it just didn't feel like it was worth the chance.

I lost 2" of floor space by having to place the base where I did, but after having to redo this apartment after a water leak ruined the entire floor (pin hole in copper pipe hidden in a wall), I have my priorities straight. We were lucky to get State Farm to give us as much as they did. They tried to blame it on roof flashing, wear and tear, etc, until I ripped open a wall in front of the inspector, and then turned on the water to this half of the house.

When he saw the pin hole spraying there was no arguing. It may have taken time to get to the middle of the room via the floor, but a leak is an instantaneous thing, even if you can't see it. Thankfully he agreed with my logic.

I wonder if Phil Swift would guarantee water tightness with a can of Flex-Seal?



HE

 

[Jeff H Young]

Im glad the hub was much lower than it looks I looked carefully at pictures and couldnt tell. youll need clearance for the drain

 

[Howard M Emerson]

Im glad the hub was much lower than it looks I looked carefully at pictures and couldnt tell. youll need clearance for the drain

Jeff,
I just made a point of making sure that there is clearance.

I think it's going to work out well. The framing is quite tight to the tile flange, so aside from finally leveling in the mortar mix there shouldn't be any more than a 1/16" difference. The compression rubber sleeve gives a drop of leeway.

Thanks for keeping me on the straight and narrow!

HE

 

[Howard M Emerson]

The shower base passed the drain leak test with flying colors.

Having accidentally dropped the 'wrench' that comes with the drain in prior installs, I figured that a magnet would be prudent:

And instead of capping the stub outs with Shark bite caps I figured I'd install 1/4 stops so I could ease off on the pressure instead of getting blasted by water.......ask me how I know......

HE

 

[ec4711313]

Jeff,
I just made a point of making sure that there is clearance.

I think it's going to work out well. The framing is quite tight to the tile flange, so aside from finally leveling in the mortar mix there shouldn't be any more than a 1/16" difference. The compression rubber sleeve gives a drop of leeway.

Thanks for keeping me on the straight and narrow!

HE

Since the drain is elevated, do you get water around the drain? My setup is pretty similar and I get water around the drain but it goes away after a few minutes, not sure if it's leaking or it's normal.