I have a brand new bathroom floor that carries right into the shower. The entire area is covered with Benjamin Grey Jerusalem stone, 1 inch square tiles. The problem is the areas around the drain have become very discolored because I believe water is getting in somehow and the tile is sitting in it, thus getting darker. The tiles were soaked in 511 porous plus and the grout was sealed as well. I have been assured the installation was done correctly, the pitch is right, the water doesn't sit on top at all. there is pea gravel around the drain and the edges are grouted and caulked. We have pulled the floor up once already but the problem came right back. We are getting ready to pull the floor up again but before we do that, we're looking for guidance on sealers, maybe using a kerdi membrane..has anyone got experience with jerusalem stone on a shower floor? thanks! Susan

is it possible that the showerpan liner doesn't have a positive enough slope underit and that moisture is just hanging out? perhaps the stones were'nt liberally sealed? This could be something you may have to deal w/? Can you post a picture?

What type is the receptor?

Maybe the weep holes aren't draining properly.

i will post pictures tomorrow. I was told the slope of the pan is pitched so well that the water should fly to the drain. I was also assured the weep holes should be clear, since they put the pea gravel around the drain the second time around. Have you done this stone on a shower floor before? thank you so much for your replies! Susan

Here's some more info -- the grout is mapei kera color U, polymer modified....i'm waiting to find out about the type of mastic...its a sunken pan, made of 3/4" plywood, 42 X 48, then there is gray rubber pan liner, then pitched concrete, then mastic, then tile. The stone was soaked in porous plus, and then grouted, then sealed again, several times.

to see some photos, go to www.innerideas.com after 730p EST and click on "tile shower." Any guidance would be greatly appreciated!
Susan

If in fact a mastic was used, that is more than likely the cause of the discolouring.
Mastic should NEVER be used in a shower, especially on a floor with natural stone.

Randall, why should mastic never be used? Did you have a chance to look at the photos?

thanks for your help.

Mastic is a petroleum based adhesive. It can support mold and is not suitable for areas that get wet daily. Additionally it needs air to set and cure. When you sandwich it between a sealed tile and a waterproof surface it's the same as keeping it in a closed bucket. The grease from the mastic can soak into and through porous stone and discolor it. Usually this looks like little grease spots and not like the problem you are encountering.

A good tile setter would never use mastic with stone or on a floor. Since it looks like your job was reasonably well done, perhaps they used white thinset.

This is such a great forum for this.
#1 My bet is the tiles are darkening from moisture,and when stones are dry all discoloration goes away.You say you used porus plus-(great product,all i've used for 10 years)with many coats. Sealers dont make things waterproof-they just kind of help the stain resistance. This -i believe- is just one more reason NOT to use a sealer. Most likely the discolored stones are from a different lot or area that got mixed in during sheet placement.
Solution: live with it for a year and stones will do different things-who knows what or replace them and not use a sealer

thanks for weighing in guys! maybe it is the mastic. but what is so curious is the randomness of the discoloration. and of course, that the darkness is going up the wall....i believe its moisture, but i am scratching my head as to how its getting in. when we do pull it up, would you recommend using a kerdi membrane? Could it be that the tiles are next to an outside wall and the temperature difference is adding to it? What if i put a radiant floor underneath? thanks! Susan

Another update: The shower floor tile is adhered with something called Super Flex. The wall tile is adhered with Double Duty Mastic. I have no idea about either product, or if they should or shouldn't be used in showers where water is present. Is Super Flex a mastic and therefore wrong for a wet shower area? thanks for your help and for understanding that I am not a professional -- i'm only trying to figure out whats going wrong with my beautiful new shower floor. Susan

Hi Susan,

Super Flex is a modified thinset mortar which is fine for the floor but mastic should not have been used for the walls. That however, is not the cause of your problems.

From the pictures, I would agree with the others that water retention is what your problem is. I would guess that there was no pre-slope under the liner. Although the tiles may be adequately sloped so that water runs off them and not pool, without a preslope under the liner, water that does get past the tiles will not by channeled towards the drain.

As Rob pointed out, the sealers help with stain resistance, they DO NOT water proof the tile and grout. You can seal it 100 times but water will still get through, albeit slowly. Without a preslope under the liner to help channel water towards the drain, the water just sits under the tile even though the weep holes are clear.

My guess is that this is a frequently used shower and that the problem presented itself after a few weeks of use as the amount of water gradually accumulated under the tile. If you don't correct the problem, the sitting water will eventually lead to mold next.

The only "FIX" that I would recommend is a complete tear out of the pan and redoing it correctly. If you use the KERDI system with a Kerdi drain, then you won't need a pre-slope. The bad news though is that the KERDI system should be used as a COMPLETE system including KERDI on the walls. That would mean tearing the walls down too however since you have mastic under there, you can correct that at the same time.

I wish I had a cheaper solution for you but we're here to give advice to do the job properly.

If you do decide to tear out the shower, check back and I'm sure we'll be happy to guide you in the right direction.

Be sure to check out the proper way to build a conventional shower base.
Constructing a Proper Shower Base

wow Colin, thanks for your reply. oh man. what to do. A couple of questions... once the tile is up, it dries out pretty quickly. Is there anyway to lift off the floor in a big block and save and reuse the tile instead of blasting it all out....? (it was really expensive) and what happens if i don't redo the walls? what will happen over time? do you think I should do the kerdi system? should the floor tile not be sealed so it can dry out next time? thank you! i defer to you guys -- you're the experts.

Susan

Unfortunately, there is no way that I am aware of to save the tile.

It concerns me a bit that the moisture is wicking up the wall. Do you know what is behind the wall tile? Drywall, green board, blue board, cement board,etc...? It is impossible to predict what will happen if you don't redo the walls without more details however the mastic is not a good start.


The Kerdi system is a very good system if you decide to use it but as I said before, you should use the complete system if you decide to use it. You should read up on it if you want to use it Kerdi system


Again, sealers are used to help with stain resistance, not keeping tilework dry.

So if moisture residuals are the problem, which weve suspected all along, then how do the tiles around the drain become stained when there is pea gravel for a three inch perimeter beyond the drain and weep holes right under it? if the suggestions are to have a pitched liner then wont the concrete bed still remain wet and restain the tile from the underside? Photo's at innerideas.com click on tile shower and you will see the staining pattern. Is the problem thermostatic? Can electric heat be used under the tiles? Is this possibly oil from the wall mastic? Is double duty mastic an oil based product? is it possible the oil from the mastic is flowing towards the drain and staining the tile as it goes. I dont know if its a drainaige problem unless I understand how the tiles immediately next to the drain stain first when this is the area that should have moisture removed the fastest. Is it possible that the weep holes are not low enough in the pan? Do the tiles near the drain stain first due to the fact they are the lowest in the pan? Finally why is it inconsistent staining....Any relevent ideas and or suggestions are welcome

Hi guys -- that last posting was verbatim questions from my contractor....sorry for the interrogation! I have learned that there is not a pre slope under the liner. I also suspect the cement board is sitting in the pan, thus the wicking up the wall. How much space should there actually be between the top of the pan and the wall cement board?

I also don't know how the mud was mixed and what part sand to concrete there is, or if an additive was used.

So -- If we pull up the floor and preslope under the liner, lift the cement board to the desired space, and start over with the mud mixture and packing instructions like Harry recommends, do you think that would be the right solution to my beautiful shower floor problem?

thanks to all of you who have become involved in my shower with me!

Susan

Hi Susan,

Are you still working with the same contractor? Is he offering to fix the problem or are you doing the repair work yourself? You mentioned that you are getting ready to pull the floor up again. Does that mean it was already pulled up once before?

Not being there, I can only hypothesize what is going on with your tile. Where to begin???

Without a preslope, the weeping holes are probably ABOVE the liner so water will pool under the drain. The pea gravel probably helps that, allowing water to flow towards the drain but the water has nowhere to go when the weeping holes are above the liner. BTW, the use of pea gravel in this manner is unconventional to say the least. :rolleyes:

The inconsistency of the stain may be caused by folds or ripples in the liner holding pockets of water at every low point.

I don't know if the walls can be saved without more information about it's construction. Did they use cement board, is there a moisture barrier behind it, etc. At the very least, about 1 ft of the wall above the floor will have to come off for the new base and liner. Post more details as you get them.

If you stop using the shower and the marks disappear or lighten, then you can pretty much conclude that water is the problem and not "Oil from the mastic.

I am quite sure the problem is not thermostatic, whatever that means....

Hi Colin, I'm so glad you replied. thank you.

I am still working with the same contractor and he is offering to fix the problem. he is trying to figure out if its the tiles,(which he can't help) or the installation (which he can fix.) Thermostatic refers to the temperature of the floor and wall, which is an exterior house wall...and if the cold has any part in the changing colors. Thats the reason for the radiant heater question.

We did pull the floor up once... thinking the weep holes were blocked, so thats when they added the pea gravel. but the problem came right back in the exact same places the floor darkened originally. This has all happened in about a 4 month time frame.

The wall is cement board. is that green board? I remember seeing green along the bottom quarter of the wall...

I will find out more.

I think you're right. the weep holes are probably above the liner, without the preslope. In fact, i was just told that effective March 1, 2008 Montgomery county maryland changed the regulations to require a preslope.

The floor doesn't dry even after several days of not using the shower. It may lighten ever so slightly but i'm convinced its too wet to actually dry. then the sealer, which the tiles were soaked in, won't let the tiles dry either...I think its not the mastic problem. but i'm not happy there is mastic on the walls. When I take down at least a foot of the wall for the new base and liner, i will make sure there is no mastic used again....

do you also think the mud mixture and the amount of packing may play a part in keeping everything wet too?

I can't tell you how important this forum has become. I thank you so much for your time and effort. Looking forward to hearing back soon.

Susan

It's good that he's willing to work with you but let's make sure he knows what he's doing this time. It is encouraging that he is willing to accept some fault. I don't know how many times I come across "I been doing it like this for years and never had a problem before...."


This should not be an issue however the exterior walls should have been insulated and covered with a 6 mil poly vapor barrier.


NO. Cement board is not green. Green board is a moisture resistant drywall but it should NOT be used in a shower at all. I believe it is no longer accepted as code for showers in most jurisdictions. There are many brands of cement board,: Wonderboard, Durock, Hardibacker to name a few. It is very important to ascertain material what was used for the walls. To answer your previous question, the cement board should stop about 1/2" above the liner so it won't wick water.


That's good news.


I figured it could take weeks to dry too. That's why I mentioned the lightening in color as opposed to the stain disappearing. At this point, even if the water were to dry out, it could still leave a permanent stain behind.


Maybe. The mud is actually designed to allow water to pass through and flow to the weeping holes via the sloped liner. The point is moot without the proper preslope.

Hi! Sorry for the silence...i became unregistered with the new site.

Colin, if you're still there, I found out the wall is definitely durock. I also found out that the mud they used on top of the liner is called Sakrete. What are your thoughts on that?

We are getting ready to demo the floor all the way to the plywood and about a foot up the wall... in the new re-installation, would you recommend that they follow exactly the guidelines on the site? Would you use the kerdi system (minus demoing the whole wall..) could it be as simple as a preslope to prevent water retention?

thanks so much. I'm happy to be back.

Susan

Hi Susan: To add a preslope to your shower would require demo up to 12 above the floor so the linercould be put behind the moisture barrier behind the so called cement board. So the steps would be
1. demo walls 12 to 24 inches above floor tear out old liner and curb if you have one
2 install preslope which would probably mean tear out old drain to raise it to the height of the preslope
3 install liner properly on top of preslope and up walls 10 to 12 inches behind wall waterproofing
4. reattach cement board to walls keeping 1/2 above liner with no nails in liner!!
5. cover liner with cement to form pan being careful to make sure weep holes are open. this layer locks in the bottom of cement board so it needs to about an inch thick
6 retile and watch the mastic on the walls fail. But this may take a couple of years...then tear out and redo with a proper kerdi system shower... sorry

Sakcrete is a brand name. It doesn't tell me what was used. They make a variety of cement mixes. If they use the concrete products, it was the wrong stuff. You can use their Sand mix with additional sand to make deck mud. I don't want to get into specifics because they may sell different products in your area than mine.



I have never done a "modified" Kerdi system before but hopefully someone else can advise you if they have. I foresee a problem with the Floor/wall joint with just doing a kerdi pan without the walls since the kerdi does not go behind the durock like the liner would.

If you do use kerdi, you should replace the drain with a Kerdi drain. Decide on which system you want to go with and then check back with us to discuss specifics

Yes, a properly installed preslope will prevent water retention. The kerdi system will keep the shower even drier since the water proof membrane will be just behind the thinset holding the tiles in.

Do you know if a moisture barrier (6 mil poly) was installed BEHIND the durock?

As the previous post mentions, you have to demolish the wall high enough to allow the new pan to go in AND allow the new Durock to be joined into the old.

Since the tiles are mosaics, MAYBE the mastic had enough to dry, time will tell. I do understand your hesitance to rip everything out because of the cost. At least you will be more informed next time.

Hi again. In the time since I haven't written, we have demolished the shower floor down to the shower liner. Pictures will be posted tonight....

The liner and mud was soaking wet. The tiles were clearly getting wet from beneath.

Now my questions are
1. How can you tell is its pre-sloped under the liner? It appears to me that there is only a sloping around the drain.
2. in the rebuild, what about putting a layer of LADACREAM 32/95 between the mortar and the tile if the new mortar mix is a heavy sand and portland cement mixture?

Should there be any folds in the liner at the wall junction?

Stand by for pictures! they were taken every five minutes for a half an hour to show the water retained in the pan.

thanks everyone!
Susan

I haven't read this whole thread, but if you see a tapered mud bed under the liner then thats the preslope. There should be folds in the corners when using a liner.