So I am checking on what my tile guys are doing during this huge remodel of my home.

I looked today and they have started on the shower.

They have put a liner down on my concrete foundation first. Then they have put a sloped bed of concrete on top of that.

From everything I have read that is not correct... right? Shouldn't the liner be on top of the sloped area and not below it?

It is starting to worry me that I might know more about shower pans than they do.

So my question to the experts is this:

Is there any reason that someone would do this other than sheer ignorance? Also, If I continue the job and have them put a liner above the sloped concrete will it somehow hurt me in the future that there is a liner below the sloped surface as well?

Thank you for your advice!

I am certainly not an expert on this but I believe the steps are:

1) Frame out the shower stall.
2) Build a sloping pre-form.
3) Place the membrane down.
4) Build the final form with the drain

I will defer to any other responses.

Thanks for the reply. That's what I thought. Now I have had two different "experts" out that are saying what has been done is correct. So what the heck?

I'm considering just applying redgard on the sloped surface and everywhere else. Then a possible negative situation would be that there is the liner below the sloped surface and the redgard. Would that create mold city?

Hi Todd...

The way I do these is to install the presloped mortar and then I put a tar paper down over the presloped mortar to prevent any abrasions from cutting into the new liner...this step cannot be skipped! Then I install the new liner. I install all my corner/threshold patches and then let the pan sit overnight for eveything to dry.

Then, the next day I fill/test the new pan. Here, I install a test ball into the shower drain and I fill the pan with water to the threshold level. I keep that as it is for 24 hours before I drain it and give my approval to install the shower mortar floor and finally tile, etc.

If I am on a wood floor I will first install a layer of tar paper between the wood and the presloped floor so the presloped floor doesn't rot the wood floor over time by trapping moisture. Then I lay the presloped mortar, then tar paper again, etc...

The layer between the concrete floor and the presloped floor shouldn't be an issue if everything stays dry. Could be the guy thinks of it as a 2nd layer of protection... as silly as that would be.

It could also be that the contractor is letting the presloped floor dry and will install the tar paper (or similar) and membrane tomorrow? Maybe?

Keep us posted on progress... OK?

Any thoughts/concerns?

Mark

Thank you for all of your help. I would really have made some mistakes if it wasn't for this board.

So I decided to take out what the previous "plumber" had done.

I had another plumber come by and check it out.

The previous "plumber" had moved some water lines for me. He busted out part of the slab and moved them. I did not see that he did not ever cover them back up. In fact, they are up higher than the foundation. They also happen to be right below the shower pan.

So, in his installation they were sticking up quite a bit into the shower liner. Then he had poured concrete all over that.

Also, he completely messed up the drain and did not even take it apart before doing the shower liner. He just took the top strainer off.

So the plumber that stopped by really seemed to know his stuff. He talked about how the guy should have used a "harder" copper or something and how it should have been soldered using a different material. I felt a lot better. Then he started telling me how he would do the shower liner and he said that he did not "pre-slope" it. He said he never presloped before putting down the liner and he basically said he wouldn't do it. So this is the third person I've had come out that either did it wrong or did not want to to put down a sloped surface first and then a shower liner second. They all think the shower liner goes down first, then the slope.

Am I wrong about something here?

The whole purpose to sloping the liner (via the presloped mortar underneath) is to force water that gets down into the concrete to fall by gravity to the weep holes in the shower strainer.

If the water doesn't get forced down to the strainer weep holes water can pool in areas and mold/mildew can begin to break down the concrete and create odors, tile/grout issues, etc.

I'd stop talkng to plumbers about this and seek help from a local tile or general contractor... they usually know how to do these.

Here is a page that describes membrane installation on a slab:

How to Build Shower Pan on Slab Floor | eHow.com

This one is almost exactly how I do my showers... ;)

Another site that agrees:

Installing Tile Shower Drain

The only thing this guy misses is the additional tar paper between the mortar and the liner. I could find you 20 sites that say the same thing... you need a preslope!

Back to you...

Mark

Thanks Mark. Now I'm just in search of someone in the DFW area (Texas) to do the work right.


I honestly feel like I'm taking crazy pills. I have now spoke with 6 different tile guys and 2 plumbers who are all saying they don't preslope prior to liner installation. They are saying they put the liner down first on the flat surface, then build up a sloped dry pack on TOP of the liner. When asked about why the liner shouldn't be sloped they just say that's how they have always done it.

I then even bring up the fact that if water ever makes it down to the liner not near the drain... what will become of it?

I just get run around answers and they always insist it won't mold. I'm really frustrated and I guess I might have to do it myself.

First you install a flange type shower drain,(see image) to descrie it it is a drain that has the regular top drain with the chrome strainer, below that you have another drain It is about six inches in diamiter and the top part of the drain screws into this bottom part. This bottom part of the drain has another part that is either bolted down or it also screws together, so actually there are three pieces to this drain. The very bottom part goes down over your drain pipe, the rim of it should be level with the concrete floor, it would not hurt if it was one quarter inch lower then the floor. After you have this on and it is sealed to the drain pipe you they cover the shower floor and up the walls with a vynal sheet of plastic.
This should roll up the walls about 8 inches but you can make it as high as you want. You do not cut the corners but fold that similar to the way you would wrap a package, this way the plastic with fit snug into the corners of the shower. Secure the plastic to the walls of the shower with staples or nails, do this as high up on the plastic as you can, you might use somekind of bushing material, like the little roofing disk so the plastic willonot tear out of the nails or staples as you are working on it. After you have the vynal in place cut a hole right in the center of the drain. Make a small hole at first, then enlarge it to expose the threads that the second part of the drain will go into. Of if it is bolted down make sher all of the plastic is under the second flange. Tighten this ring tight to the bottom part of the drain. Now screw the third part of the drain into the second part and adjust the height to how thick you want you Quickset or mud for the tile or what ever you are going to cover the floor with. Make sure you have a sloope in all directions toward the drain.
Doing it this way any water that would ever get through the floor of the shower would be caught in the plastic and the drain is built to let this water drain into the sewer drain.
If you had one of the double seepage drains in your hand it would be very easy to understand all of the above. Good luck, Tom

So Tom, contrary to what everyone else has said thus far I am getting from you that you put the liner down first in you installs. The other people on this thread and many other places on the web say to put down a sloped material first, then the liner, then the top coat that will be tiled. This makes more sense to me to do that.

In your post you mentioned to put the drain, then the liner, then slope the material on top of that. So you disagree with others about sloping first and then putting a liner on?

Hi Todd...

Tom is not talking about a vinyl liner with a regular drain. He is talking about a "double seepage drain".. see his image. In 30 years I've never worked with one...

We don't use these in my area. We either use the vinyl membrane and a vinyl membrane shower strainer (see image) or we use a copper pan.

In other areas they use hot mopping for showers... ;)

In your area they may use these double seepage drains? As Tom asked... do you have a drain that looks like the one he posted or does your strainer look like the one below?

If it looks like my pic... then you'll need to preslope before installing the vinyl. If your drain looks like Tom's pic. Then you may be just fine as things are!

Wait for Tom to repost, too!

Mark

Up and down the Southwest Gulfc coast that's the only way I've see showere\s installed with the exception of a slab dap out that's hot mopped with a regular drain.
But I've been retired for 22 years so mew methods have been developed. My apologies for the confusion. Just as Mark has never built a shower pan out of Vinyl Compaseal with a flange type shower drain I've never seen a tile man mud and slope the floor in first and then install the liner.
I'll check with some tile guys and see how we're building them now.
Sorry about the confusion, Tom