ARRGH! I’m not sure if I should post this here or in the Pit, but I’ll try here and watch my language.
Background: 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 inch cement board (or whatever that stuff is called) 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 the recommended products.
It looked great. It looked like it could have been done by a professional. I was proud.
Now I’m pissed off and frustrated.
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.
OK, fine. 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. Any dopers 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?
The mortar is laticrete 220 marble and granite mortar. Just and water, mix, and go. I did rake the mortar using a 3/32" x 1/8" x 1/8" trowel (the 3/32" is the depth of the notch, while the 1/8" is the notch width and spacing).
On first glance, I would guess that a heavy marble tile would require the thinset to be raked at something more than 1/8". Did you allow the mixture to sit before applying? This is called slaking, and it’s a nuance to tiling. That’s why they always tell you to work in small areas with small quantities. If it doesn’t slake long enough, the mix won’t adhere well. If you make too much, it slakes too long and gets dried out. Another good peice of evidence is to see where it’s coming off. Is it coming off the tile or the cement board? Dust on one side or the other will make a bad adherance, but if it’s a mix of the two, I’d consider the thinset to be the source. Did you allow a set and then pound in a bit when you set them? How aggressive did you pound if you did, because too hard will cause problems as well.
There just is too much to go over. That’s the hell of those home improvement books that gloss over things. There is a lot that goes into tiling, so picking up a used, but more detailed, book on tiling might get you better info. And heck, when you’re done with the book, just sell it back!
Good luck. In my house, I retiled my bathroom twice, and my kitchen twice. I’m finally happy with them, and the third bathroom I did was perfect first time around. So experience helps.
For what it’s worth, my office building has had to replace the granite tiles on the outside wall three times in as many years because they keep falling off. Looks like you’re in good company.
Thanks NurseCarmen, I beginning to think the 1/8" trowel is the main culprit behind the problem. I did correctly slake the mortar and cleaned both the tile and backer with a damp sponge before setting the tile. I also pounded a bit with a 2x4 wrapped in a towel and a hammer (not too much though I don’t think).
If you have any other ideas you can see a picture of one of the tiles that fell off here. All input is very much appreciated!
Wow… and to think I never wanted to do it again when I finished. You have my admiration. The tiling wasn’t too bad but setting the cabinets was a serious pain in the keester.
From your picture, it looks like the bond to the backerboard is the issue. Dunno why that would be, but I notice that the Laticrete has a superflexible additive for mounting over plywood. You shouldn’t need it for the base you have, but it might not hurt to use the additive this time around – might provide a bit of extra give if thermal expansion or deflection is the issue.
Hmmm, I agree that I shouldn’t need it with the base I have and I also agree that it couldn’t hurt, however now I have questions if I’m using the right mortar. From the Laticrete website I’m wondering if the mortar I used is the right kind.
I’m also beginning to think that my coverage wasn’t that good. In the picture I posted, are the groves supposed to be mashed down more that that? Does it look like I was getting good coverage?
Did you trowel the mortar on the cement board, or did you “butter” the tiles?
If you put it on the cement board, then the problem was the stuff didn’t adhere to the board. From the pic, you had a near-total failure of the mortar bonding to the board.
If you buttered the tiles, it looks as if you didn’t get any contact between them and the cement board. At least not enough for any mortar to contact the board - another vote for “wrong trowel”
gotpasswords, I buttered the tiles. I’m going to put them back up now using a different (larger) trowel. I’m also going to “wet” the backerboard with the mortar before buttering and placing the tiles. Hopefully they will stay up this time and hopefully no more tiles will fall off.
