Ceramic tile question
 

Last year I tiled a shower in a rental apt. It's about 3x8 with the shower itself taking up about half the area. Floor was concrete and I was tired of painting it. I used small octagonal b/w tile. The tile outside the shower is holding up fine but the tile in the shower itself is failing. Some have popped up and others can be moved around in place. What might be the cause of this? I followed directions on the setting compound and the grout. I'd like to avoid this problem in the future. I assume the volume of water hitting the tile is the cause of the problem since the area outside the shower curtain is fine. I've seen a lot of tiled showers that seem to be holding up fine. What did I do wrong?

I do not think tiling a shower floor is as easy as just directly tiling ontop of the original concrete floor...from my understanding, above the wood subfloor...should be mortar, then some sort of PVC membrane, another layer of mortar, and then the actual floor tiles...water inevitably seeps through the grout lines in a tiled shower floor and will run through the mortar, collect in the membrane, and then be directed to the drain hole where the excess moisture is allowed to run off via small weep holes...it is actually a very elaborate installation that takes a bit of skill...

My best guess from what you are saying is that you do not have the proper installation underneath your new tile floor to deal with the excess moisture that runs underneath the tiles...

DuckMuck is correct, Kerry. You must have some sort of membrane between the thin-set mortar and the concrete floor. Grout remains fairly porous even after sealing, particularly in a shower setting. I've had great success - twice - using a paint-on, very rubbery coating whose name escapes me. I got it at either HD or Lowes - I suspect they still carry it. It came in a gallon size paint-type can. A fairly bright pink in color. I put two or three extra heavy coats and never had any problems. Much simpler solution than the thick, heavy, floppy, pain-in-the-arse rubber membrane. Good luck! nk

I'm thick. Can you explain the role of the membrane/coating? What difference does it make whether the thinset is on the membrane or the concrete? Won't water get thru the grout anyway if it is porous? What stops the tile from popping off the membrane/coating the same way it has popped off the concrete? I was under the impression the membranes were used to waterproof the floor itself. In this instance, it's a solid concrete floor that's been a shower for 75 years.

The membrain has a few reasons for being...

Its a vapor barrior (concreats allways outgassing, it doesnt dry to my knowlage)
and, concrete expands and contracts at different rates then ceramic tiles.

You say its in a rental, are you sure there wasnt another reason for the tiles being moved?



I'm using some construction adhesive to resecure a few tiles in our bathroom... buying time for the remodeling (like summer after next type of deal)
I'll let you know how that works out

The membrane collects the water that permeates through the grout lines and the thin set mortar...this water is collected by the membrane...the membrane is sloped towards the center of the shower stall to a special drain that has small "weep" holes along its outer edge to allow the water/moisture to drain...if this moisture does NOT drain, it will just sit there...and slowly work its way through the cracks/weakness points in your mortar until it breaks down...unlike the membrane which is some sort of plastic, or in the old days lead, concrete itself is porous...it will hold water...so the moisture that soaks through the grout lines and through the thin set mortar just soaks into the concrete and holds the moisture...

The key is the weep holes along the drain that allows the moisture to run off, and the membrane that acts as a big basin to collect the water and direct it towards the weep holes...with the concrete, it just acts as a big sponge and holds the moisture...which will sooner or later cause the thin set mortar to weaken and your tiles start to pop off...YOU NEED TO REMOVE THE MOISTURE THAT SOAKS THROUGH THE GROUT LINES AND UNDERNEATH THE TILES!!!

you could also use a water proof cement mix to set the tiles. same thing with grout. sealing is critical. 3x min. then periodically one has to reseal it. say once per year.

you sure you had enough of the mortar under the tiles? memebrane is nice i but i don't think it's necessary.

Here's the reply I got over on the John Bridge tile board after I was asked whether I mixed my own thinset or bought it in a pail:

It stays pliable in the pail because it can't dry out...same thing in the shower...it never really dries. You need REAL thinset, made with cement. Once cured, it is a rock, not rubber like that will soften when it gets wet. If you plug the drain, and let water sit in the shower pan for a day or two, you will probably be able to scrape them all off that part of the floor, including the mastic (which is what it really is if it was in a pail, regardless of what they say on the label). Reset them in real thinset, and at least the floor will stay intact. The walls are another matter.
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Jim DeBruycker
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My experience says that he's on the money. I have used the premixed "thinset" and it definitely does not fully harden. Along the edge of the tiles, the mixture remained dry but somewhat pliable. It definitely seemed like the wrong material for a kitchen or a bathroom.

I recently bought a 50 lb. bag of the proper thinset that is sold to contractors. Rather pricey at $30.00 but the stuff dries like a rock. I tiled a bathroom floor with it using the mosaics. I'll give it 10 years and see how it does...........

yeah mastic is crap. use the other stuff. pompeii/hurcelano mosaics are still there and they were set in some crappy 2000 y/o cement. cement is the way to go. i have set tiles in just it w/o a prob. no need for some fancy shmancy thin set. :D

Oil thread alert!! I think the new mastics are the only way to go, and I use it on everything but marble and granite to great success.:eek: If Kerry would have used a proper mastic, he would not be having the popping problem. I would say not enough cure before using the shower and or improper mix on the grout.

Grout was pre-mixed and the shower sat for weeks (in our very dry climate) before use.

Second opinion over on the tile board was also not to use the pre-mix but mix my own thinset.

Damned expensive lesson. I hate redoing work.

Like I said--bad mastic. If it were a commercial job, I would have turned it into the mastic rep. for reimbursement. Don't know if they warrant retail purchases directly.

what did you use as a backer to the tile....greenboard or cement board? Were they properly grouted? What tile gap and did you use sanded or unsanded grout. Like many things the foundation is key to a long lasting job. Shwer stall floors must have a membrane propperly installed. Is you froblem with the floor or the wall, I didn't see that in the post.

Regular sheet rock will not hold up long in a shower even with a proper tile job.

I did my two bathrooms 7 years ago and used ceramic tile over cement board, using thinset not mastic. Never had any problems on either the floor or walls.

You wouldn't use greenboard in a shower....