Ceramic tile question - PeachParts Mercedes-Benz Forum

kerry · #1 05-01-2006, 07:34 PM

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?

DuckMuck · #2 05-01-2006, 08:06 PM

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...

NKowi · #3 05-01-2006, 08:16 PM

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

kerry · #4 05-01-2006, 08:39 PM

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.

Nate · #5 05-01-2006, 08:46 PM

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

DuckMuck · #6 05-01-2006, 09:09 PM

Quote:

Originally Posted by kerry edwards

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 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!!!

mzsmbs · #7 05-01-2006, 10:17 PM

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.

boneheaddoctor · #8 05-02-2006, 09:22 AM

Quote:

Originally Posted by kerry edwards

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?

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.

John Doe · #9 05-02-2006, 09:25 AM

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

boneheaddoctor · #10 05-02-2006, 09:27 AM

Quote:

Originally Posted by John Doe

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

Lot of new contruction does use greenboard....which I will agree is not the best thing...cement board is the right way to go. I used cement board behind all tile and greenboard on the non-tiled wals and the ceiling for the moisture resistance in both my bathrooms.

mzsmbs · #11 05-02-2006, 02:17 PM

Quote:

Originally Posted by boneheaddoctor

Lot of new contruction does use greenboard....which I will agree is not the best thing...cement board is the right way to go. I used cement board behind all tile and greenboard on the non-tiled wals and the ceiling for the moisture resistance in both my bathrooms.

yup. but a lot of contractors skimp on even that and they just use green board on everything if they use green board. i have seen a lot of drywall backing tiles in the bathrooms. it's called job security.

John Doe · #12 05-02-2006, 02:36 PM

Whoa, I missed something major here. Mastic is not pre-mixed grout. The mastic I am referring to is an adhesive that you use to install tile, it is not grout. I think the brand my old company is using now is Chapco, btw. If that stuff failed, the company should honor your re-install costs if your surface was proper.

Bone, I meant installing the actual shower tiles on greenboard. Destined for failure. It is perfectly fine for kitchen backsplashes and wall tile in the head.

kerry · #13 05-02-2006, 09:51 AM

Quote:

Originally Posted by boneheaddoctor

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.

It's the floor which is 75yr old concrete. Shower walls are some kind of solid stone also 75 yrs old. I think it was sanded grout, but it was a yr ago so I can't be sure. It was the most expensive pre-mixed grout at HD at the time.

It's definitely a problem with the mastic because besides the ones that popped up, I can get the ones still in place to move slightly, as if they are set in rubber, when I pry on them. The ones directly underfoot when taking a shower are the ones that came up.

The irony is that I chose the pre-mixed mastic and grout because I thought, as an amateur, it was possible I would mix the non-premixed stuff wrongly.

boneheaddoctor · #14 05-02-2006, 11:03 AM

Trust me I am not in the construction business..and am no pro with this either....I learned quite a lot watching this old house and hometime...and did research online....ordered my stuff from a local tile shop that gave me design ideas and installation tips beyond what I already learned. The basics are really simple to learn. I have since did both bathrooms and my kitchen in ceramic tile. And still have neighbors begging my to do their house at whatever I want to charge ( I really don't have the time or motivation to do it for them). Have you determined if the stone or mortar surface you are trying to put the tile on is solid and stabile? As in not deteriorating allowing the mastic bond to come off with base material attached? If thats the case you need to address that problem first. I was of the opinion mastic is fine for a kitchen backsplash but determined on my own I didn't want to use it on the floor or batroom at all. Mostly becasue it needs to be adsolutely solid, and rigid or the grout will fracture and lay open a path to water to get behind it.

Also did you use a toothed or a flat edge trowel? a flat straight edge will put excessive adheasive compond down be it mastic or Thinset.