Toilets, Sinks, Showers, Tubs and Disposals - Help with shower tub.

I bought my house 5 years ago. Since the day we bought it, we knew one of the bathrooms would have to be gutted and redone. We hired a contractor friend to do the job last October. We've been happy with the results, until this past week. During a massive rain storm, my son showered, and we had a leak into the basement which was coming from the new shower stall. We didn't know if it was the bathroom, or the storm. At one point, we thought it might be the drain backing up from all the rain. My friend came to see and actually opened the wall on the outside of the shower (the hallway) to see if any water was getting behind the tile. This was done directly above the leak, but the shower had not been used in 24 hours. Nothing appeared wet, so we went on inspecting and eventually found an unglued vent pipe in the basement, and we assumed that was the problem. He agreed to come back over the weekend to redo the vent pipe (which was from the original bathroom - he never touched it).

Now.......fast forward to tonight. My son takes a shower, and it occurs to me to look in the basement, where I find new moisture, but the vent pipe is dry, so now we can rule out the vent joint being unglued. I come back upstairs, and decide to open up more of the wall, and I saw that the membrane under the shower base was holding about 2 inches of water between it, and the concrete board (basically the bottom row of tiles in the shower. It then occured to me that the big leak from Friday had to be caused by water overflowing the membrane.

The old bathroom had a plastic shower base, but the drain was centered over a joist, and whoever built it, had cut the joist. My friend repaired the joist, and to put the new drain off-center, he had to build the shower base as follows........

Plywood on the bottom. (3/4 inch)

Cement board on the walls (1/2 inch)

Rubber membrane over plywood and coming up about 8 to 10 inches over the wall.

Poured concrete over the membrane. Concrete was shaped so water drains to the middle.

Tile over the concrete, and tile over the concrete boards in the wall..

The joints where the floor meets the wall, and the walls meet each other are caulked, and everything else is non-sanded grout.

So now the question(s) are:

This membrane is not supposed to have 2 inches of water in it after someone showers, correct ?. The membrane should remain dry and only act as a barrier if something fails, like caulk, grout, drain, etc.......is that right ?. I just want to make sure I am not going to be told this is normal. Clearly, the leak came from water overflowing the membrane.

From what I listed above, does the method for building the shower look right ?. Was something missed ?

Thanks for the help. I can post pix if needed.

PS: In case the shower needs to be redone, I may want to give up on the concrete base and go back to the plastic base. Does anybody know if they make these with the drain off center ? It only needs to be off center about 4 inches to clear the joist.

Update: So I expected the water to drain out overnight. This morning, I went to look and the same amount of water is still there, which now tells me this water has been there a while. In fact, the water looks kind of yellowish to me. Perhaps the original grout didn't set enough before we started using the shower ?.

Still.....I fear we are going to have to rip out the 8 month old shower to get at the problem.

Argh.

From your description, I assume you mean moisture has wicked up the cement board about 2 inches? You don't mean that while in the shower you are standing in 2" of water correct?! Is the shower 2 walls or 3? Are all the walls wet? Which ones? Have you checked the shower valve or shower head for leaks behind the wall? Does the vent stack exit the roof very close to the shower stall? Yes pix would definitely help!
JoeP

From your description, the shower was not built correctly, and your pan is holding water. Water is not making it to the weep holes in the clamping drain due to lack of a preslope underneath the membrane (required by code and you do not have one), or the weep holes are clogged and water is not able to escape to the drain.

Tile, grout and caulk are not what makes your pan waterproof, the membrane is designed to do that. As water seeps through the grout lines, it should flow through the mud bed where it should reach the liner and then eventually make its way to the drain weepholes. It sounds like this is not happening with your shower.

The shower is 3 walls. The wall that has the plumbing has not been opened yet, but the problem appears to be on the opposite wall from the shower.

This is what I think is happening......

The shower stream is hitting the far wall, and water is getting behind the tile and the cement board, probably thru the grout.....the water then wicks down the cement board to the membrane and gets trapped between the membrane and the concrete slab that is the shower pan.

What I remember from the pan being built is plywood, then liner, then concrete, followed by tile. I do not recall any sort of preslope or any kind of weephole, but would love it if someone could point me to an illustration of either or both.

Right now I am just trying to figure out how to fix it without ripping out the shower, or assuming the shower gets knocked down and redone, how should it be done so this problem does not reoccur.


Thanks for the help.

fx

Do the grout lines on the shower floor appear to dry out and lighten to their original color are do they always appear to be dark and wet?

See this link on how to properly construct a shower. It will show the preslope and the clamping shower drain with weepholes.

Building a shower pan with pre-sloped mortar bed, liner and curb. (http://www.ontariotile.com/preslope.html)

Any water that makes it to the panliner should be able to make its way to the drain through the weepholes.

Here's and example of a clamping drain with weepholes.

Shower Drains for Tile Shower Bases :: Oatey.com (http://www.oatey.com/Plumber/Shared/ProductGroupDetail/115/Shower+Drains+for+Tile+Shower+Bases.html)

Heres the basics of how its supposed to be done.....http://www.oatey.com/shower_drains/lit/Shower%20Pan%20Liner.pdf

The pics are a little hard to see.

No expert, but if you didn't have a presloped bed under the liner...you may as well plan on ripping it all out now, before you start getting rot and mold problems. Sorry

You may want to consider using the Schluter Kerdi system if you really want a waterproof shower. Some people consider it expensive, but its cheaper than having to rip it all out and redo the damage caused by an improper install.

EDIT
Ahh didn't see Johnny was around....so take his stuff as gospel..

The shower stream is hitting the far wall, and water is getting behind the tile and the cement board, probably thru the grout.....the water then wicks down the cement board to the membrane

That is a good possibility, however it should not result in a problem. The concrete slab you refer to should be a mix of approx 1 part portland cement and 4 to 5 parts sand. It is a solid stable mix but water should filter through it very easily. If the membrane has a proper preslope under it and the weepholes are not clogged, this water should easily drain properly.

EDIT
Ahh didn't see Johnny was around....so take his stuff as gospel..

Ah gunguy you are too kind.:) The info you provided is all good stuff as well.

you may as well plan on ripping it all out now

Yeah that is most likely the case. I hate to be the bearer of bad news.

I actually had found that link just before I read your post.

Thanks for the info.

I don't believe that a preslope was done or mortar was used. I'm not sure if mortar vs. concrete makes a difference but I'm pretty sure it was concrete. I think I even remember seeing fiberglass reinforced concrete.

I could be wrong but I don't think the liner was laid on top of the concrete and then followed by more concrete. I think this was liner on top of plywood, followed by concrete, followed by tile. This may be the whole problem, now the question will be how to fix it without ripping out the entire new bathroom. And, for all I know, the weepholes are covered with concrete.

I'm thinking we may have to rip out the wall about 4 feet up, and bust up the pan, and then redo the whole bottom part again. I don't think I'm going to be comfortable with any sort of quick fix. You know how it goes.....once you lose confidence in the job, paranoia sets in.

Or maybe, I'll just try to find a plastic pan with an off center hole. Still don't know if they make those..........anybody ?.

Hey I just looked at both your locations.....

Johnny..why don't you just go up and take care of it this weekend? Nothing like a little extra work..right?

Oh wow.......Johnny you wouldn't be in northern NJ by any chance.

Gunguy what are you trying to get me into know. Fortunately, we still have a big backlog. When you see me here in the daytime theres one of two reason. Either the back or the knees arent in operating order.

I'll take that as a no.


:wall:

fx...there are any number of reputable tile guys...and you CAN do it yourself with some help here.

Unfortunately, your contractor friend didn't know what he was doing in this case, or wrongly assumed that he did. Laying flooring tile, and building a mudbed tile shower are 2 very different animals. At the very least, I think he should come back and do the removal, even if you prefer he not do the repair.

My friend said he would stand by his work and if anything needs to be redone, it will just be materials as far as my cost.

I will post back when he examines the situation and gives me a plan of action.

You're right, the instructions you guys posted look straightforward enough.

Well, that sounds good. We'll wait to hear how it turns out. Just one last thing to remember. Cement board, mortar, sand mix, grout are all water permeable substances. They are water resistant, as in won't be damaged by moisture, but they are not waterproof.

You have to have some sort of waterPROOF barrier directing water to the drains somehow. I really think thats the biggest thing to always be thinking about. If water can find its way where it shouldn't be, it will. Its just the nature of the pesky beast.

Got it. Thanks a lot. I'll keep knocking on wood.

I agree thathe shower floor was constructed incorrectly. However, I would love for HeresJohnny to explain how the water trapped between the liner and the mud bed climbed 8" over the liner Rubber membrane over plywood and coming up about 8 to 10 inches over the wall.
to soak the CB.
Always looking to learn!
JoeP

Heck joe...don't need johnny for that. We don't know where or how far the liner was run up to, and normally, theres the plastic on the studs behind the CBU. The original installer could have put plastic on the studs..then the liner over the plastic..then the CBU.


Take a 2 foot long piece of CBU and put it in 2-3" of water...it will wick up at least a foot..maybe more if it can't evaporate off the upper area.

Until its torn out and we really see what was done..no one really knows.

There is no mud bed. It's concrete.

If you mean plastic like a vapor barrier there isn't any. The liner comes up the stud wall about 8 inches like I said, and he installed the cement board over that right to the studs. The water is caught between the liner and the bottom of the cement board. If you pull the liner back, you can see the tub base underneath, which we already discussed is constructed out of concrete and is therefore not letting the water drain.

One thing of note......the water spilling over the liner is only a theory at this point. Thru the opening in the outside wall, I saw 2 inches of water last night. There was 2 inches of water this morning. There is still the same amount this evening, so the amount of water that is trapped has remained constant, and is about 4 inches from the top of the liner.

Now, keep in mind I am seeing this thru one of two walls. I still need to open up the other wall to see what the deal is there, but I am waiting for the contractor to come and see for himself. I suppose it is possible that the liner went higher on one wall than the other, and that would account for the water spilling over in one area, and not the other.

One thing that is clear is that water got thru the tile and the cement board right where the water stream hits the far wall. I can see the drip marks on the cement board. This is the wall that is open right now. The leak into the basement happened around the corner by the other wall, and like I said I think maybe the water found its way around the corner studs and spilled over finding its way into the basement right where the vent tube is (which has a partially glued elbow and we thought that was the problem until we found the liner problem).

So......there IS a problem with the shower bed and the liner not draining. There IS a second problem with the unglued vent elbow below the shower. The leak was substantial last Friday, but has not happened again although I did notice some moisture when my son showered.

Again, I will post when the full story is revealed. If time allows, I'll even post pictures.

Building a shower pan with pre-sloped mortar bed, liner and curb. (http://www.ontariotile.com/preslope.html)

I looked at all the pics. The landlord (my boss) has a rental that is an older house with no reason to believe the tiled bathroom (half-tiled walls and tiled floor) and tiled shower (walls and pan) was not original. And if not, it has been original enough for many many years with tenants using it. I can't believe that such a carefull elaborate system was done. And I do not think they had such flexible rubber membrane way back when. Obviously IF anything was used, it have to be something flexible and water proof so that it has no seams at the corners. Poly? -maybe? There is no caulk between the tiled shower floor and tiled walls that intersect at the pan. It's grouted.

I have a mind to go there and pop the drain cover to see if I see such a drain that has side entry weep holes or not.

To my knowledge, the floor is not rotting out. But after reading this post, I'm going to make it my point to go there and see what I can see from the basement perspective.

fx...true, you said no mudbed (kind of a general term) but if it is really concrete, which I totally believe based on what you said....its just soo wrong in soo many ways. Even a non-pro like me can tell....

Hope it works out well in the end..waiting to hear....

Well you guys made me stop watching the Yankees play the Mets and go take some photos. Please don't flame. My friend tried his best, and I went along with what he said without getting a second opinion.

The shower

http://i126.photobucket.com/albums/p113/montespythonmusic/PICT0109.jpg


The outside wall

http://i126.photobucket.com/albums/p113/montespythonmusic/PICT0110.jpg


Closeup on wall cutout

http://i126.photobucket.com/albums/p113/montespythonmusic/PICT0112.jpg


Looking down the hole

http://i126.photobucket.com/albums/p113/montespythonmusic/PICT0113.jpg

OK, so now.....assuming a tear down this is what I think I am looking at.

If you look at the first picture I posted, I am thinking rip up the shower base and the wall up to the accent stripe in the middle, and rebuild from there.

So......rip up would be one day. (also fix vent pipe).

Laying the mud bed.....

Pre-slope layer - one day
Liner and second layer - one day
cement board and retile - one day
grout - one day

So conceivably.....four day's worth of work ?. Does that sound about right ?.

The shower is 3 walls. The wall that has the plumbing has not been opened yet, but the problem appears to be on the opposite wall from the shower.

How did you come to that conclusion? Does the grout look cracked back there? Or mildew built into the caulk back there?

The shower stream is hitting the far wall, and water is getting behind the tile and the cement board, probably thru the grout.....the water then wicks down the cement board to the membrane and gets trapped between the membrane and the concrete slab that is the shower pan.

If the grout looks bad, inspect, redo and seal it after 72 hours, if necessary.

Who would ever want a membrane system to even have water get to where even moisture is trapped down there? I, being a handyman, would almost rather see water stains on the ceiling below a shower pan, so that then I'd simply correct the grout. This way you can tell if it ever leaks.

And that is even if that is what is happening. Maybe there is a problem with the drain itself that may be allowing water to instead of go down the drain, goes back into the weep holes instead, and gets ontop the membrane.

However, I would love for HeresJohnny to explain how the water trapped between the liner and the mud bed climbed 8" over the liner Rubber membrane over plywood and coming up about 8 to 10 inches over the wall.

joeperi

I don't believe that it climbed up over the liner. My interpretation of what fx is saying is that the water is trapped between the liner and the cement board, so its all inside the liner, it didnt climb over. This is quite possible if the mud bed is saturated. If there is no preslope under the liner, water will seek the lowest spot, and can easily pool between the liner and the cement board, then it will gradually make its way through the grout joints.

fx

Is there blocking between the studs that is supporting the pan liner? It does not look like it from your pictures. There should be blocking around all the walls between the studs to fully support the pan liner.

Ecman

Tile and grout aren't what makes a shower waterproof. It is in fact the liner that does that. This type of shower is designed such that water will get through the grout and tile, and it will be directed to the weepholes in the drain. Unfortunately, this particular shower was not quite built right.

Hmmmm. Don't mind ME too much on this thread as this system is actually new to my knowledge bank. The whole thing strikes me as odd though.

You mean they actually want water to get through the tile and grout? That seems so strange. I can't imagine they went thru such an elaborate construction process with old systems.

How would have they built such a syestem, with what, say 30-50 years ago? What would the 'membrane' be made of?

I would have just thought that perhaps they laid down some tar paper, in case plain old moisture (not some lake of water mind you) got thru the concrete and then poured some concrete and that be all. And perhaps came up with a way of making sure they did not have a cold joint between the plaster wall and concrete floor pan? - maybe formed at same time, and using that wire mesh to lock it together to prevent crack there?

The house the landlord has that has one of these tiled pans/shower walls is a plaster house and I think more stabilty is in the corners where they use that wire mesh when plastering. You never see vertical corner cracks, for instance, in such plastered houses. This would make it so that it be less likely there would be grout failure, as well, in those corners.

I'm just dying to have an excuse to go to that rental and check out that drain and also view up from the basement.

..................................................................
Ecman

Tile and grout aren't what makes a shower waterproof.

Sure is good that must not apply to my parents tiled shower walls that are only over sheetrock for the last 37 or so years. We know that water is not going to go through ceramic tiles. That leaves the grout. I thought that is what good grout sealer does, was seal the grout?

BTW - just so you do not feel you have to go on any 'defensive' regarding things I am bringing up in my post, I am not simply trying to be arguative or sarcastic. I actually am fascinated by this procedure as this is something totally new to me.

If **I** ever had such a system built by some tile pro, I'd sure want to know that the person had prior experience in this, and took the care of a surgeon in getting it all just right, so that the whole thing did not cause the very thing you would be trying to avoid.

HeresJohnny,
Now that I see the pictures, your explanation makes sense to me. Thanks for your patience.
Regards, JoeP

Ecman...you know I'm no Pro....but...

They used to use sheet lead (and copper, I believe) as pans, way back in the day. Pretty much the same as the PVC liners are used now. And reading through some other places I've seen people that found roofing felt used as a moisture barrier between studs and sheetrock/greenboard/plaster. Now the standard is poly under cement board and the PVC liner or the Kerdi system which as I understand makes a completely waterproof enclosure.

And while the sealer may help with water penetration..I think its main function is to help prevent staining. And it needs to be reapplied on a regular basis.

I believe epoxy grouts are pretty much waterproof and stain resistant, thus require no sealing, but they appear to be expensive and harder to work with. Many Pro's say there is no real benefit considering the cost and labor involved.

Just some basic info I've seen in various places.

Thanks Gg, you are probably right about the lead I bet.

I went to that rental today after I repaired a bath/shower mixer valve leak today, and had to make access panel to find where the water was leaking from.

In that tiled shower pan drain are indeed weepholes! 3, I think. One was clogged with thick orange rusty scum. I cleared it out. All 3 had rusty water mark streaks weeping out of them. I'll be.

Sure glad nobody hired me to build them a shower stall. I probably would have just poured sloped cement, and tiled. I then would have patted myself on the back or rubbed my chest with my fist at how nice it looked afterwards - only to have it leak like a sieve!

I took a look from the basement up, but they cold air return-type chased (no cold air return though) the entire plumbing run over to the stack. Huh. Maybe they did that so they could build the stall, and leave the county before anyone ever noticed the underside of the floor getting damp and black. :D

I also asked my boss today, who recently had such a stall built in his expensive house, and he said he indeed had a membrane system done, the way the pics on this site describe it. But then he told me how this rich guy in town with a million dollar home, who had a walk-in closet size tiled shower built, with the membrane system, had it leak, and he ended up calling my landlord's tile man to redo the job! Just like what the OP said he had to do!

An update: the friend came over with another friend. They think it may be the weep holes so they will try to find out for sure tomorrow (how....I don't know)......but I will be watching.

Today, I saw several other web sites where they refer to the tub base as being made of concrete. I understand the difference between concrete and mortar as basically being the presence of aggregate (or not).......so the questions are........isn't concrete still porous, but perhaps less so than mortar ? and therefore the preference for the latter ?

and........which is the type of mortar that should be used in this application.....type N, type S, etc.

Is the stuff that comes premixed in bags at HD and Lowes stores good enough, or does it lack something ?.

Just trying to get it right the second time. Personally, I am really rooting for it to be the weeping holes.

fx,
According to several books I've read on mixing up deck mud for the shower pre-slope and floor you can choose either
Portland cement and sand mixed 5:1 (5 parts sand to 1 part Portland cement) or you can use Quikrete Sand Topping Mix.
I'm sure there are other prepackaged products out there that will suffice.
JoeP

That WOULD be something! - to tear up a perfectly good stall because weep holes were blocked!

In my case, with the one weep slot being plugged - it only stands to reason this woud happen over time. It does with anything else with water trickling through it.

What is the best tool, wire, catheter, tobacco pipe cleaner,?, to use in cleaning out the weep holes so you do not damage say the membrane? And to 'feel' that all is clear back up inside.

Well.......I would not call it a "perfectly good stall", since it isn't working like it is supposed to. My friend's cohort did say he has used concrete in the past......maybe he meant mortar......he also mentioned something about some sort of rib system you can put under concrete to give water a path under the slab.....anybody know anything about that ?.

The more I think about this, the more I come to the conclusion that there is no preslope like Johnny said. I find it amazing that after having the wall opened for several days, and without using the shower, the amount of water in the liner has remained exactly the same.

Anyway, tomorrow we will open the rest of the wall and take a good look, and start what I hope is a partial demolition. We will also look into the vent pipe down below.

I will repost (hopefully more pix) when I have something useful to report. In the meantime, I want you all to wish me luck, 'cuz I think I need it.

Beer 4U2

The more I think about this, the more I come to the conclusion that there is no preslope like Johnny said. I find it amazing that after having the wall opened for several days, and without using the shower, the amount of water in the liner has remained exactly the same.

Since there is no positive slope under the liner, the water will seek the lowest spot which is aparantly at the wall in question.

Here is what needs to be done.

The tile floor and deck mud must be removed and the mud over the curb as well. The wall tile and cement board must be removed approx 18" to 2' above the floor. The pan liner liner has to be removed. The drain will have to be reset a little higher to accomodate the deck mud preslope. Make sure it's the right kind of drain, see the link above. Make sure the drain is properly secured to the subfloor after its reset.

This is a good time to make sure that the studs are notched at the bottom to accomodate the pan liner so that it will not bow out the cement board. The corners where the folds will be are of particular importance. Add blocking between the studs to fully support the pan liner. The blocking should be high enough so that you can attach the liner to it approx 3" above the finished height of the curb.

Now onto the preslope. Attached builders felt and diamond lath to the floor. You'll want the preslope deck mud to be approx 1/2" to 3/4" in thickness at the drain so make sure the drain is set accordingly. The preslope pitch should be approx 1/4" per foot, so the deck mud will be thicker at the walls, curb etc. Make sure the proper deck mud is used. I gave you info on this above. If the finished surface of the preslope has some birdbaths, fill them with thinset so no water can pool when the liner is installed.

Now you can install your pan liner. Take a look at the link I gave you above, as its pretty complete I think. Make sure you use preformed corners at the curb and where needed, as these areas are particularly susceptable to leaks. Make sure the liner has no nails at least 2 or 3" above the finished height of the curb. Make sure you test the pan for leaks before you go any further. Blocking off the drain with a pneumatic plug. Fill the pan with a couple of inches of water and make a mark on the pan liner with a sharpie at the water level. Leave it overnight and check the next morning to make sure the water level has not changed. Hopefully, no leaks.

Now you can install cement board on the walls (but not the curb). Patch in poly vapor barrier to me with the above and lap over the pan liner. The reason I said 18" to 2' above, is that you must have a large enough piece of cement board that you can attach it to the studs above where the pan liner ends. No screw penetrations through the pan liner. Set the cement board so that it stays approx 1/2" off the bottom of the pan liner. Your final mud bed will "lock" the bottom of the board in place. Oh yeah, forgot to ask, a poly vapor barrier was installed behind the original cement board right? This keeps moisture from entering the stud cavities, that can cause mold and rot problems.

Install diamond lath over the curb/pan liner. Use fat mud to mud the curb. No cement board or nail/screw pentrations through the curb. Fat mud is nothing more than mason's mix. You can buy it bagged at a supply house or big box store.

Now you can do the final mud bed. The mix is the same deck mud mix we already talked about. The final mud bed should be approx 1 1/4" in thickness, and should also be sloped 1/4" per 1'. Fill any birdbaths with thinset before setting tile.

Make sure that a good quality modified thinset is used to set the floor and wall tile.

Good Luck

Edit: Forgot to mention, make sure pea gravel is used around the weepholes to prevent deck mud from clogging the weepholes. This is an important step.

Johnny

If you look at..hmm post #21? and the pictures...he said no vapor/moisture barrier between the studs and the backerboard.

Thats why I thought it should be a complete ripout. A shame too, the tile work looks pretty nice.

If you look at..hmm post #21? and the pictures...he said no vapor/moisture barrier between the studs and the backerboard.

Ok so that answers my question on the vapor barrier.:thumbdn:

Thats why I thought it should be a complete ripout. A shame too, the tile work looks pretty nice.

Over time, there could/will be mold and rot issues. Tough call as to whether its a total demo or not. If I were the homeowner, I might insist on it as many things were done wrong. At the very least, proper repair of the pan as outlined above is in order.

HeresJohnny,
Question: Since we know that moisture will travel through the final mud bed to the liner, If you use the final mud bed to lock in the CB don't you run the possibility that moisture in the final mud bed may wick into the CB?
JoeP

Joe

Yes. The cement board will wick some moisture, however it will not hurt the cement board. If the pan is draining properly, this wicking should be minimal though. Additionally, the vapor barrier behind the cement board should divert any moisture that gets behind the board back inside the pan liner. Interesting that you ask this question. There are some pros that are of the opinion that the cement board should not be buried in the deck mud as the cement board can wick moisture.

I should follow this up by saying that you can install the cement board so that the bottom is 1/4" or so above the final mud bed. This will eliminate any wicking issues, however you have the last 6" or so of cement board "flapping in the breeze". The thinking here is that the cement board and tile will be rigid enough to hold up for the bottom 6" or so. Some do it this way, but I dont.:)

Edit: Official TCNA manual states to keep cement board "out of mortar bed/caulk bottom edge". So there you have it.

It is my intention to avoid complete rip out. There is a reason the tile looks nice.........it's EXPENSIVE.

Anyway, the repair is now postponed until at least June 29th, due to complications on both sides (my schedule and the other person's).

I intend to use the advice received here as a guide, as well as this document which pretty much says the same thing.

http://www.oatey.com/shower_drains/lit/Shower%20Pan%20Liner.pdf

OK, so the repairs began today.

Demolished the floor and halfway up the wall.

Found.....

No preslope as Johnny suspected. Also found that the outer edges were actually low spots, and that's how the water stayed there....in fact....the drain was about 1/4 inch higher than the edges.

Found the weep holes were clogged.

Found the leak was from water permeating the grout lines, and finding its way thru a gap in the cement board (in the corner).

The fix will be:

redo the pan as described (preslope already laid in).....will add spacers on top of weep holes, too.

redo the bottom half of the wall, and make sure the corner doesn't have a gap......(open to suggestions on best method to seal a joint between two sheets of cement board)......I was thinking cut a strip of membrane and glue it into the corner using thinset or maybe an adhesive of some kind....

reinstall the tile.

seal the crap out of everything, especially the grout.

redo the bottom half of the wall, and make sure the corner doesn't have a gap......(open to suggestions on best method to seal a joint between two sheets of cement board)......I was thinking cut a strip of membrane and glue it into the corner using thinset or maybe an adhesive of some kind....

The corners and all cement board joints should be taped and mudded with thinset. Make sure you use the alkalai resistant tape made specifically for this.

From your response, it sounds like you may be under the impression that cement board is waterproof. It is not. While it is unaffected by water, water will pass through it. Kinda like a puddle on a concrete slab.

Thanks Johnny......that is exactly what was done for the corners......and I understand that NOTHING is waterproof, just water resistant.

By the way the new membrane now goes up the wall just about 14 inches.

Most important, is to make sure you have a preslope under the pan, use pea gravel (or something else) around the weepholes and install blocking between the studs to fully support the pan liner.

It all done except for grouting, and we used tile spacers over the weepholes.

Sounds like a better job the second time around.:)

One can only hope.

Anyway, the job is now completed. I am going to let everything sit over the weekend so the grout and the caulking have a chance to completely set, and we'll see what happens when we use the shower again.

Thanks to everyone who helped. Using the advice here I was able to talk things out with my friend who really went out of his way to make things right for me. It did cost me some money for materials, but he ate all the labor which was 3+ days.

seal the crap out of everything, especially the grout.
One last step before you are done done! Good luck! :D