Shower floor leak

[hylomatt]

While testing a fix for my show floor drain, I found that the closet flange wasn't completely sealed to the floor of the fiberglass shower shell. Water was running under the toilet, past the flange, down the hole onto the top of the tank and falling on the ground. So after I removed the toilet and closet flange, dropped the holding tank and cleaned up the area, I can see that this is not a recent development. Probably the last person to try to fix this made the problem. The closet flange was epoxied to the floor and also it was cracked. There were a couple of extra screws through the flange and into the floor as well.

So I'm trying to figure out how I can fix this without tearing up the interior of my RV. If I had my druthers, I'd be able to carefully disassemble enough of the shower shell surrounding bits to slide the shower out into the hallway or just enough out of the way to pull out and replace the rotten wood bits. Then reassemble it all, etc.

When I say rotten, I mean that I can push a fingernail into the wood or grab the wooden ring underneath the shell (and around the 3" pipe beneath the toilet) and move it easily. It's not coming apart under its own weight but I could break most of it out of there using two fingers. Definitely not strong enough to keep the floor from flexing when someone sits down on the toilet.

Does anyone have any insight for me here?

 

[Matt Colie]

Matt,
If the bad wood is in structural places, it will have to be replaced. You should be able to replace those areas that are structural from underneath. With good epoxy like West system, you should be able to scarph in the new section or sister the joint adequately.
When I had the flange up to drop the black tank, I laid a bead of caulk around the floor flange to both seal it from leakage (we do use the shower) and hopefully prevent the new screws from corrosion.
Matt

 

[dsmithy]

Matt,
Look on this forum at: "Forums>GMC Motorhome Forum>Marketplace>Parts for sale>Free Bathroom" for some pictures of what's under a '73 bathroom unit. You may find some helpful info in that thread.

 

[bdub]

Link:

Free bathroom

I have a 1976 Eleganza II that I have removed the interior from in prep for rebuilding. I carefully removed the bathroom and would prefer not to put it in the dump. Here is my craigslist posting for it. https://seattle.craigslist.org/see/zip/d/seattle-free-rv-bathroom/7477065289.html Anyone...

www.gmcmotorhome.org

 

[hylomatt]

@dsmithy @bdub Yes, thanks for that link. That was my post that prompted that helpful response. In retrospect, I wish I hadn't hijacked that other thread. I usually behave myself better than that

 

[hylomatt]

My diagnosis of the issue:

The sealant between the closet flange and the shower floor had failed and was allowing water to run onto the wooden plywood/pressboard support that the toilet's flange was secured to with screws. This allowed the toilet to move about whenever you put any weight on it. Thankfully, no cracked ABS or clogged lines.
I was able to extract the wooden support in pieces and then chisel and sand the remaining edges of it smooth and out of the way for my fix. Although the wood didn't feel 100%, I couldn't dig my nails or small screwdrivers into the remaining wood any more than I could newer wood. I think the remaining wood was fine to leave in place for now.

---

My solution:

I wish I had taken photos of the various steps and pieces used but I didn't and so I'll describe what I did, in case it can help anyone else.

I dropped the holding tank, removed the closet flange, and cleaned off all of the old sealing material. I had to build a good support for the toilet, since the original plywood/pressboard pieces was swollen toast. I bought 3/4 inch plywood, cut multiple "square-ish" pieces and drilled a 4 inch hole in the center of each. I sawed them in half, so that I could fit them through the hole in the floor and through the access in the rear of the shower wall. I laid them in layers, rotating each layer 90 deg offset from the previous layer so that no cut line lined up with the one above or below, and glued each layer to the previous layer. This formed a nice, solid base to support the shower floor under and around the closet flange. After that was done, the whole stack was secured to the wooden base (the plywood right above the holding tank) with a perimeter of 8 lags. Mild countersinking was done to make sure no touching/rubbing would occur between the lags and the plastic holding tank. I then reinstalled the holding tank. Then I installed the new closet flange, with ample silicone sealant beneath, and then screwed the closet flange to the floor and into the stack. Then I used silicone around the flange and notches so that any water in the floor of the shower that managed to make it underneath the toilet would run beneath the shower. Then with a new flange seal, the toilet was installed. Nice and solid, no flexing or ability to stress the shower floor.

---

I also lined the base of the toilet all around with plumber's putty. That seal is not as nice as I would've preferred since it's always ready to collect dirt and hair but it has stayed clean so far. I don't want to use a hardening sealer because I don't want to fight with get the the toilet lifted up if/when I need to do so again. I'm tempted to remove this putty but it could be the 1st line of defense to keeping the floors nice.

Anyway, just trying to tie a bow on this story and provide some data for how I resolved the issue. If it had been worse, meaning real rot and poor to no floor support for the shower, I would've removed the walls and shower shell somehow but luckily, that proved not to be necessary. If that day comes, now I know a lot more about how the shower fits in the RV and what the underside looks like and I'll be ready to rehab it.