glass tile is cracking [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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12-13-2016, 09:27 PM
Our master bathroom was completed in August with glass tiles (4x12s and 6x12s) on the walls and marble on the floor and bench. The glass tile has begun cracking and we currently have 9 tiles that are severely cracked. Needless to say, we have been reading everything that we can about why this is happening (obviously the tile guy did not do something right and our GC says she is working on figuring out what/why this is happening.) I will post a few pictures from when the tiles first started cracking and will take and post some more (with the feathering in the next few days). Any and all advice is great--this GC had good reviews and we had everything permitted but it didn't seem to matter!

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12-13-2016, 09:37 PM
You'll need to fill us in on how the shower was constructed. Unfortunately glass is a little iffy in showers do to the temp swings that occur from use. Without proper construction glass tiles are prone to cracking. And in some cases cracking can occur with all the proper precautions in place.

12-13-2016, 09:40 PM
Welcome, SM. :)

We're gonna need a lot more information to even begin guessing.

1. Brand name, make and model of the tiles.

2. Brand name, make and model of the bonding mortar used.

3. Brand name, make and model of the grout.

4. Substrate over which tiles were set.

5. Framing over which the substrate was installed.

6. Treatment of grout joints at all changes of plane in the shower.

7. Water containment method used, i.e. type of waterproofing membrane if any.

If you have any "during" photos of the shower construction they might be very helpful.

Let's start with that and see how far we can go.

My opinion; worth price charged.

Houston Remodeler
12-13-2016, 10:23 PM
Sabra contacted me through another forum. She sent me the same pictures plus these:

12-13-2016, 10:35 PM
If this shower has a pan liner type of water containment, nailing cement board to the curb should not have been done. It has nothing to do with the tiles cracking but will cause other problems down the road.

Houston Remodeler
12-13-2016, 10:38 PM

1- Glass tiles shouldn't be cut into L shapes as they are very prone to cracking. Its highly advisable to spend some time on the layout of the plumbing fixtures as to avoid L shapes. Where L shapes are mandatory, the inside of the L should be as rounded as possible, spreading out the stresses as much as possible.

2- Its easy to see from the quality of the cuts and the L shaped tiles, these guys aren't well versed with glass tiles. With the proper blade, the cuts should be clean and crisp with no rough edges. Watch this video ( for the fastest, easiest way to cut glass tiles, then this video ( of glass tiles being cut with my favorite glass cutting diamond blade.

3- There seems to be screws through the top of the curb holding the ceement board (CBU) into place. This is a no no. Due to the rest of the shower construction we can see, there should be a vinyl liner underneath which they breached with the screws. Hopefully there should be no screws on the inside of the curb. Do you remember any?

4- The ceement board isn't waterproof. Do you remember any sheet plastic over the studs? If not, the red stuff should be covering the entire surface.

5- The ceement boards on the floors should have thinset underneath them. Do you remember any thinset going onto the plywood right before each board was placed?

Houston Remodeler
12-13-2016, 10:41 PM
how glass tiles can be cut

Todd Groettum
12-14-2016, 06:52 AM
I am not going to second guess the methodology used here but the Workmanship looks pretty good ( other than the durock curb top and without knowing the type pan done I would be simply surmising)
It is natural when something fails to want to blame someone, hell, anyone but there are times when it is a material problem, Not a workmanship problem...

This could be one of those times....I guess all I am saying besides "I hate GLASS Tile" :deadhorse is Lets not hang the installer just yet, not without more input....

And as a side note I can Hate glass tile...I am retired and no longer have to deal with it...:D

MAPEI - Technical Service
12-14-2016, 10:16 AM
Are the inside corners grouted or do they have silicone sealant in them? From the picture it looks like they're grouted. If that's the case, you have nowhere for any expansion in the glass to go and that's a very likely contributing factor to your cracking. Glass expands a lot, you're heating it up in the shower while the substrate behind it is still cool. That expansion needs to go somewhere and the soft joints (the siliconed corners) are designed to do that.

Houston Remodeler
12-14-2016, 04:33 PM
I have talked to three installers and shown them the pictures. They do not have any idea while the tiles would be cracking. I am going to go to Floor & D├ęcor to speak with them about the tile. I will update you as soon as I have more information. We installed your tile with flexible thin set over cement board.

Does this sound right? I thought that you had to put a waterproof membrane for glass not just cement board because of the expanding and contracting

There is no such animal as a 'flexible' thinset. They all cure hard like cement, because that is the primary ingredient after sand. The membrane does provide some measure of movement protection, but generally as one large wall panel and not per individual tiles. Perimeter joints being properly filled with 100% silicone caulking give room for expansion and contraction, aside from being required by the TCNA.

Further, the waterproofing is required no matter what type of tile is on the surface. Full waterproofing to 70 inches over the bathroom floor is required by the United Plumbing Code (UPC) See attached document. Your local plumbing code may or may not have a different name, but generally they all follow the same requirement for waterproofing (again regardless of the surface tile)

Sounds like he has no idea of the specifications for glass tile installation and now is blowing smoke in every direction.

12-14-2016, 04:34 PM
thanks for the replies. I believe that the grout was added directly to the cement board and then the tile was added. I'm not sure about the nails.

Houston Remodeler
12-14-2016, 04:38 PM
To bring you up to speed on the correct terminology to help you understand;

Thinset is the mortar used between the tile and the ceement board

Grout is the mortar used between each tile.

You see the grout in the finished product. You should not see the thinset on the finished product. The grout has no role in bonding the tiles to the cement board.

12-14-2016, 05:28 PM
FWIW, cement based products bond by growing interlocking crystalline spikes...those spikes are fairly brittle. But, they can bend slightly (think glass). A modified thinset provides a slightly less rigid coating between those crystals...helping to support them and offering a microscopically small space for slightly more flex...but, all of that flex is VERY small.

Tiger Mountain Tile Inc
12-14-2016, 06:20 PM
I'm trying to see where he used mesh tape for the seams and it doesn't look like he used any. In post 1/photo 1 there's a cracked tile next to the niche. If it's the niche on the back wall then there is a vertical seam in the cbu right there.

The cement board install looks ok before mudding the seams. It looks like it's 16 oc and staggered boards. Except for the curb part of it obviously. But the curb isn't causing the wall tile to crack.

Do we know yet what kind of thinset was used and who manufactures the glass?

Houston Remodeler
12-14-2016, 07:25 PM
I found the glass manufacturer, if its the right one, with the instructions you'd expect (

12-14-2016, 09:47 PM
me again--thanks for the help with this. I'm assuming the bigger bag is what was used on the marble portions of the shower (floor and bench) and that the smaller bag was the glass tiles (they had me pick out 3 different colors--one for the floor, one for the marble and one for the glass tile)

12-14-2016, 09:49 PM
I think that the first picture is the stuff that was used on the glass tile

argile tile
12-14-2016, 10:16 PM
my non-professional observations are, (excluding most all comments above which i think are all pertinent), is ...

i hope the cinder block was not left in. cinder blocks hold mold unless proper drainage and temperature parameters are (provided). i had to fix my own outdoor mistake last year by adding drainage (which worked)

i see poorly cut glass (winning lotto one)? if i cut a window poorly with a glass cutter it still may break before installation after the initial edge snap.

that cement/fiber board cannot hold all that downward weight, it would bow (someone above mentioned attachment method). in addition - it is directly on drywall (thus compaction to stud). studs move and bending the whole fiber board horizontally would cause a center vertical break? (if one stud stepped into room). so if not attached right it bows, but if attached indirectly to stud, it might still bow. it's winter the house may be creaking from the hot/cold cycles.

i've had two door peephole break on me (i scratched delicately when cleaning - a single grain of sand across the lense: as soon as the door closed it broke. the other broke when someone slammed the door). lesson: not all glass makers make tempered glass

the best thing to do before buying a product is look for people who've been trying to file complaints about (ie, breakage) on the web. ie, reviews - but not reviews that homedepot or the glass maker have control over. in this case you may learn statistically if the tile has cracking issues.

argile tile
12-14-2016, 10:32 PM
if the tiles were set rapidly with tile adhesive or wet mortar, if so rapid the spacers held things by pressing on the tile below because the mud did not stop a "downward slide" (the spacers pressing on lower tiles did): then lower tiles might be cracking by having large uneven pressures built up and set in when (it) dried. if so, replacing would remedy the issue.

Houston Remodeler
12-14-2016, 10:53 PM
I'll wait for the guys from Mapei to chime in. :corn:

12-15-2016, 06:38 AM
We thought that by hiring a licensed contractor, who was having everything permitted, we would not run into problems!!

Houston Remodeler
12-15-2016, 07:18 AM
You lernt that wasn't so true.... Permits don't help all that much.

12-15-2016, 07:22 AM
Big difference hiring a licensed general contractor than hiring a competent TILE installer. You get what the GC gives you as far as installers. Not always the best.

Dave Gobis
12-15-2016, 08:39 AM
Which makes me want to tell one of my favorite licensed/certification stories Evan. Was presenting a one week Intro class on tile installation at WFCA in CA. The second day one of the attendee's didn't show, not all that unusual. He comes in on Wednesday, said he had to take his C-54 test and passed, which is a California Tile Contractor license. After working with him extensively all week I can say he didn't take to tile installation very well. He was a straight up guy so I asked him how he passed the test. His reply was the test was split in three sections, tile being one of them. He aced the first two and knew just enough about tile to eek out a passing grade. His business plan was to sub out all the work, he just needed a license for whomever to work under.

12-15-2016, 01:52 PM
That right there keeps this forum going.

12-15-2016, 02:45 PM
Many places do not require any real knowledge to hang up a sign advertising 'tile installation'...some states do and there is a national group that can provide some certification that's good, but in reality...if you say you're a tile installer in many places, even with no experience, you can legally do it. Doesn't make it morally right, though. Plus, some people are great at making an installation LOOK good, but the bones were not done properly and it often won't last long. So, it's hard to just look at a finished project without some followup to see how it lasted. SOme people don't expect much and if something cracks or comes loose years down the road, they assume it just 'wore out'. Well, a proper tile job is a lifetime should last pretty much until you decide you want a change, at least in our western timelines. In older civilizations, say Europe or the far east, things have been up long enough to literally wear out the tile installations, but they're still intact, just worn thin or away.

12-15-2016, 05:40 PM
Texas is full of installers like that. Tomorrow morning I will be looking at a shower that has white sheetrock covered with Redgard. Two of the walls are tiled. Not a cheap house, high dollar part of town. I see it over and over.:shake:

12-15-2016, 06:53 PM
Today I talked with a local company who thinks the issue may be due to the quality of the tile rather than the installation. I really am upset and frustrated by this--Any advice, recommendations at this point? :bonk:

12-15-2016, 07:54 PM
Have the installer replace the cracked tiles, even if you have to pay him for it. After talking to him about that, ask him to show you where it's an acceptable standard to fasten CBU on the inside and top of the curb when using a traditional pan liner system. Tell him that's his goof and make him redo all that on his dime.

I have to disagree with Argile, there's nothing wrong with the concrete blocks. There's nothing in cement to harbor mold.

I'm like Todd, I hate glass tiles too and I'm not retared. :)

Houston Remodeler
12-16-2016, 04:36 PM
I had the pleasure of stopping by Floor and Decor today. Checked out the glass tile section which was quite extensive. According to the fellow who runs the department, this is a new line of tiles to F&D. There are no information on any box, nor inside any box noting ANSI or installation.

When its daylight tomorrow I will wet cut and dry cut my sample tile to see how it handles. Video and comments to follow.

Tiger Mountain Tile Inc
12-17-2016, 12:19 PM
If the glass is from AKDO then those instructions are pretty good. Much better than a lot of glass that's out there. But is the glass made to any standards? That's the question. It's not unusual for the glass to be part of the problem or even the whole problem.

But if the backerboard seams aren't taped then at least part of it is installer error also.

Photos 2+3 in the top post aren't the thinset that was used to set the glass. There's a white mortar on the walls and the Mapei thinset in the photo is gray. So we still don't know what mortar was used to install the glass.

Houston Remodeler
12-17-2016, 06:39 PM
Here is the video ( I made handling the tiles.

Overall I give the tiles a B+. They cut well upside down with a wet saw and a decent glass blade. They do not snap well at all. The backing looks like it will get a good bond to good thinset BUT since the back of the tile is very textured it should be back burned before setting.

If the installers didn't back burn and made things worse by not flattening the trowel ridges before setting the tiles, I can easily see the glass tiles cracking.