Tiles falling off... What did I do wrong? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-10-2003, 11:05 AM
Hi all, great board. I was very happy when I found this as I have a bunch of tiling jobs I was planning on doing in the next year.

Anyway, that's not the point of my posting. I was hoping someone could give me some advice regarding my kitchen countertop. Almost exactly one year ago I redid my kitchen counters with granite tile. I though I did everything right. I set and leveled all my cabinets. I used 1.5 inches of plywood as the base (2x 0.75 sheets held together with screws and liquid nail). I then put 1/4" underlayment on top of it. I put down the 7/16" thick 12"x12" tiles using the recommended mortar with 1/16" gaps between the tiles. I used an un-sanded grout and sealed the whole counter 3 times using products that had been recommended to me.

It looked great. It looked like it could have been done by a professional. I was proud.

Now I'm pissed off and frustrated. :mad:

Two of the tiles have fallen off in the last month and I noticed today that three more are about ready to go. They are only being held on by the grout. All of the tiles that are coming off were (are) mounted vertically. The two that have already fallen off are 12"x1.5" edging pieces below the countertop (if you see what I mean). The three other pieces are roughly 6"x9" mounted behind the stove. All of the pieces are free hanging, meaning nothing was (is) supporting the tiles from below. The only thing that holds these tiles in place is the mortar.

I can put the tiles back up. I still have some mortar, grout, etc... But why did they fall off? Also, a friend told me about a liquid nail product that is especially made for tile. Another person said not to use this with granite as it will come through the tile and discolor it. Does anybody out there know about this? Is there anybody out there that can give me some advice on what I did wrong? How can I make this counter permanent? Is my whole counter top going to come apart?

More details:
1.5" Plywood base
Fiberrock brand underlayment (1/4" - attached to plywood with screws and liquid nail)
Laticrete 220 Marble and Granite Mortar applied with a 3/32" x 1/8" x 1/8" trowel.
Laticrete 1600 Series Unsanded Grout
Sealed (3 times) with Stonetech Proffesional Impregnator Pro.
I can also attach pictures if requested.

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06-10-2003, 11:17 AM
Hi, Eyer8! Welcome to the forum? Got a real first name?

A couple of things come to mind: How long between the time you spread the thinset and the time you placed the tile (the thinset could have skimmed over). Did you let the thinset "slake" or rest between the time you mixed it up and when you mixed it again before applying it? Was the backerboard dry and dusty?

On the pieces that fell off, does the thinset still cling to the tile, or the backerboard?

The pros will be along later with more questions, in the mean time, go ahead a post a picture or two. The guys seem to work better with pictures. ;)

06-10-2003, 11:52 AM
Hi bb, thanks for the welcome.

For these tiles, the mortar was spread on the back of the tile and the tile was placed immeadiatly. Regarding the slaking, I believe we waited about 15 or so minutes before we started setting the tile after we mixed the mortar. The backer board was cleaned with a damp sponge immeadialy before setting the tiles.

Of the pieces that fell off, the mortar is (mostly) mostly sticking to the tile (see the picture below). On the other piece that fell off, it had more sticking to the backerboard (maybe 15-25%).

My camera has very low resolution, but hopefully it is clear enough to see.

06-10-2003, 11:54 AM
Oh, by the way... my name is Alan.

Derek & Jacqui
06-10-2003, 02:33 PM
Hi Alan,
Welcome to the board, not to sure, but that looks like the tiles on the drop my be stiuck to Pine, that could be the problem.

06-10-2003, 02:52 PM
Hi Derek,
Hi Jacqui,

Thanks for the welcome. The tiles are actually stuck to the Fiberock Underlayment. You can get details on the Fiberock backerboard at this website (http://www.usg.com/Product_Index/newprod_fiber.asp). The backerboard protudes past the maple cabinet by about 1/4". I can take a better picture if you want.


Rock polisher
06-10-2003, 03:47 PM
Judging from the picture you didnt bond in part from not pressing the piece in hard enough. You shouldnt have trowel ridges standing up like that after drying. Its also a good idea use the flat side of a trowel and scrape thinset to the edge you are going to stick to. It helps ensure a good bond. scrape the thinset off and reapply. Your friend is right , liquid nails will bleed through most granites. Yours a light colored I definitely would not use it. As far as the rest of your counter coming apart, time will tell.

Dog paws
06-10-2003, 04:12 PM
A trowel with larger teeth might help. Try bumping up to a 1/4"x1/4"x1/4" square notch.

06-10-2003, 04:25 PM
I gotta go with Jeff ( aka Rock Polisher). I have seen this happen before where the thinset is keyed on the tile but never "bonds" to the CBU.

When working with CBU, I mix my thinset a bit wet. This allows the CBU to sucks some of moisture from the mud w/o drying it out. Also, it helps with CBU to put a skim coat of mud on the CBU ; then trowel on the tile. This gives a better bond

Sometimes the mud doesn't stick to CBU if it it not troweled directly over the CBU


06-10-2003, 04:37 PM
Thanks All!

When I put these pieces back on I will follow your advice and you know... Is there any special trick on cleaning off the old thinset?

Dog paws
06-10-2003, 04:45 PM
Grind it off with either a carbibe or diamond blade.

John Bridge
06-10-2003, 05:55 PM
Hi Alan, :)

Gotta throw my two bits worth in here. I've never quite understood why USG came out with Fiberock and recommended it for tile installations. I mean, they are the makers of Durock cement backer board, which they claim to be the best in the industry. I think Durock IS a good product, but I don't think Fiberock is as good, not for tile applications, maybe as a floor underlayment for other types of flooring.

In any case, it seems to me that you would have to really key the thin set into the Fiberock (which is made from gypsum and not concrete as is Durock).

I know this is all a bit late, but I want to put it here for others who will read this thread. Use cement backer board for your tile projects. Do not use products whose primary component is gypsum.

Now, I think you can put the pieces back on with more thin set. Mix it very loose, and make sure you damp sponge any dust away from the Fiberock. "Burn" a little thinset into the Fiberock, and then butter a bit on your piece. Push it in all the way.

I want to beg the pardon of my friends at USG. Fiberock, while it may be a good underlayment, is not the best product you have for ceramic tile substrates. We'll keep on recommending Durock here. ;)

06-10-2003, 06:34 PM
Thanks John & everyone else.

Great Board!

06-10-2003, 09:11 PM
without so many words, i agrre with john, and dog paws with the notch size. another perspective may also be to upgrade the thin-set you are using.

Bill Vincent
06-11-2003, 05:29 AM
John, I gotta agree with you. I'll use durock over fiberock or hardi any day of the week. It just seems to hold the tile better.

06-11-2003, 06:41 AM
this site never ceases to amaze me on the wealth of knowledge available. I just learned an enormous lesson here reading these post. John's comments on Durock have now been burned into my memory.
Now can someone help us rookies know the differences between Durock, Fiberock, Wedi, Hardi, others?. A person can find tons of references here to each of when doing a search, but I have alwyas assumed they were the same just marketed under differnt names by differnt manufacturers. Some look easier to work with, but if you have these sort of adhesion issues..wow. A table listing the differences would be great..sorry if i am asking for something crazy or unreasonable here..just smack me and i'll get over it...

Derek & Jacqui
06-11-2003, 07:34 AM
When I hang tile or granite on the counter top I use the margin trowel to butter the piece then rub it back and forth till it won't go back any more, most times it will hang there without having to use duct tape.

Art in Stone
06-11-2003, 11:31 AM
I think the fiberock was an attempt to compete with Hardi with an almost identical material. Why they went with Gypsum :confused: . I agree with you Bill cement board is the next best thing to mud.
that might be a good idea. You can always go to their sites and see what these products are composed of. That's their main differences.
Durock: Is basically a 90% Clay, cement, silica body( and other stuff also) with a fiber mesh exterior.
Fiberock: Is 95% Gypsum, cellulose(paper), and silica.
Wedi: The body is made of "Styrofoam"*(extruded polystyrene) and exterior is fiber mesh with synthetic resin modified mortar.
Hardibacker: Is 95% Calcium Silicate, crystalline silicate(quartz), and cellulose.
Woderboard: Is basically same as Durock.
Rhinoboard: 99% Portland cement, cellulose fibers, and silica sand.

John Bridge
06-11-2003, 07:27 PM
Well, I have some friends at Hardie, too. :D

Hardi-backer is a good product. It is mostly cement with just a little fiber running through it to give is cohesiveness. Hardi-plank is about the best siding (cladding) out there, too. Same material, basically.

Burning the thin set in is the key to getting things to stick to a lot of substrates. The substrate can be clean and dust-free, but if you don't smash the thin set into the surface, you might be in trouble down the road.