Cement board install question.

[Chester Kaup]

I have removed all the tile in my shower. When I removed the bottom 4 rows of tile on the wall it pretty much destroyed the morter bed on top if the liner. I removed the morter bed up to a previous joint. The liner appears to be in good condition with no leaks. There is now a groove all the way around the pan next to the wall. In some places it is level with the floor and in other places as deep as 3/4". Should I fill this groove and then put on the cement board leaving a gap between it and the floor or what is the best way?

[scut207]

Pictures would really help, I can't quite wrap my head around what you're trying to describe.

[ckl111]

How old is the shower? Even though the liner may still be good now, that can change and the last thing you want to do is replace a liner when all your new tile is in. Your old drain could be corroded down below too.

I would complete the demo rather than trying to patch an iffy liner and base.

[Chester Kaup]

Looks like you are right about taking it all out. The more I remove of the wall the more problems I find. Total removal to the studs in progress.

Now a question.

Originally the shower had two layers of sheetrock, then metal mesh and finally cement on the metal mesh. Why the two layers of sheetrock and do I need to put it back before the cement board?

Thanks.

[AdamP]

I'd do cement board only. It's possible previous reno's were done where people just kept going over what was there.

The other problem is you have to worry about the wall thickness for the rest of the bathroom. Is the rest of the bathroom 2 sheets of sheetrock?

Also, have you thought about what type of waterproofing you're going to do?

[Chester Kaup]

The shower is built in such a way that the walls of it never butt up against the rest of the bath walls so no problem there.

Please elaborate on what you mean by waterproofing?

[AdamP]

Cement board contains no organic material, so it will not mold, but it is indeed not waterproof.

One option of waterproofing I would suggest is the Kerdi membrane. There are a few different options. I suggest doing a few searches on this website.

Just remember, wood studs -> cement board -> tile & grout is not a waterproofed shower.

You need something like:

wood studs -> moisture barrier -> cement board -> tile & grout

or

wood studs -> cement board -> waterproofing (i.e. Kerdi) -> tile & grout

Me personally, I like surface waterproofing right behind the tile & grout, but everyone has their own preference.

[cx]

Welcome, Chester.

With a traditional shower pan you have the option of installing a moisture barrier of poly or roofing felt behind your CBU walls or applying a direct bonded waterproofing membrane over the inside of the walls. You must do one or the other, but you must not do both. You require no vapor barrier unless you plan a steam shower.

My opinion; worth price charged.

[Chester Kaup]

I cannot get a test plug to seal in my shower drain. It is a expendable rubber plug. The drain pipe is cast iron and very rough on the inside. I am afraid a ballon will just pop and never seal. Suggestions?

[cx]

Chester, it'll help if you'll keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered. We can give it a more generic title any time you'd like to suggest one.

Thought you were tearing out all the old stuff in that shower? Guess that didn't include CI drain and trap, eh?

You can try a wire brush on your drill to clean out that pipe some. Might help, might not. Then try a lot of Vaseline on the inside of the pipe and outside of the test plug.

If that doesn't work, you might wanna remove that drain riser and trap and replace it with PVC or ABS pipe. Kinda late in the game if you're doing a flood test, but it'd still be a good idea before you get any further along.

My opinion; worth price charged.

[Chester Kaup]

Sorry about the posting etiquitte.

I only took out the walls of the shower back to the studs. The pan had been replaced previously and still looked in decent shape. I though I would test the existing pan and if it was OK I would not have to remove and replace.

Thanks for the ideas.

[cx]

I have occasionally, against my better judgement, been talked into replacing only the pan of a failed shower, but there is no way I'd ever spend my customer's money re-building the walls over an old, questionable, shower pan. And never would get to be even a longer time if the existing plumbing was cast iron.

But it's entirely up to you what you do in your house, eh?

My opinion; worth price charged.

[reefone]

im with cx on this one. a new liner is about $50 and a few bags of sand topping mix isnt much either for the piece of mind it will give you.

[Chester Kaup]

I took your advice and removed the old shower pan liner last night. Turns out it was not installed correctly. There was no slope to the floor and the drain was higher than the surrounding floor. Unfortunatly the cast iron drain pipe broke off about 6" below the floor. Now a couple of questions.

1. The floor has about 4" diameter hole where the 2" pipe comes up through. When I put in the new PVC drain pipe do I need this gap around the pipe?

2. How thick do you make the sloped floor under the liner?

Thanks.