We installed 5″x5″ Italian glazed porcelin tile, idenified as “Gelsomino Field 5×5 Grazia”, on a countertop that we rebuilt and when finished everything looked great with the molded edges. Yet, about two months after installation little “cracks” began to form across numerous tiles. By five months time, about 15% of the tiles had these small cracks.
Now, the cracks had no pattern indicating stress points, nor did several of the cracks even go across a whole 5″ tile. Some cracks were perhaps 2″ long starting and ending in the middle of the tile! Furthermore, none of the cracks could easily be felt as I rubbed my hand across the top of the tile. The cracks appear to be below the surface.
I spoke with a sales rep from Century Tile, where we bought the tile, and he called the condition “crazing”, and seemed to indicate that this was a normal process. Needless to say, my customers who purchased the tile and dealt with the sales staff are at a loss–they were never informed of this process, and frankly they simply don’t like it.
What is the story behind “crazing” tiles and is this truly a normal process?
Curt
St. Charles, IL
Replies
I just Googled "crazing tile" and got a load of stuff on it. I've never seen it before, but it looks to be normal and even desirable with "high end" tile.
I didn't really see a time line, but I get the impression that crazing takes years to develop. It seemed to be helped along by moisture. (like most things <g>)
Thanks! I too did a search online and found "crazing" to be "appealing", but I never thought that a sales associate would sell a tile like this without properly informing the customer.
Thank goodness they picked out the tiles and not you.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Yeah, I also noticed that the client picked them out. Boris, what's your take on these tiles? Any experience with them?
Any glazed tiles, as opposed to a porceline tile, will have some minute cracking of the glaze, either developed during the firing process or after. In reading the post I assume it is only the glaze, and not the actual tile bisque which is cracking.
But no, I have never seen a type of tile which is purchased for an attribute of intentional cracking of the glaze. I guess some persons could find that attractive, but to me its like buying jeans with bleach stains already on them, or a car with intentional dents, or a pen which leaks on purpose. I don't find the cracking appealling at all, unless the application is a part of a design with faux antiques (paint crackling and distressed furniture).
My two cents.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Yeah, it sounds like the owners were not aware of this "feature". (it's not a mistake, it's a feature)
Heck, I've seen old tile have crazing, but I didn't know new tile would do it so quickly.
Typical Italian stuff.. looks great, falls apart. :)
Crazing is fine cracking of the glaze only, with no damage to the body of the tile. Crazing is normal with some tile, and even done intentionally on some for decorative effect.
It is caused by using a glaze with a higher coeficient of thermal expansion than the body clay. Glazes can be made to not craze if the manufacturer desires.
If the sample tiles on display at the store did not show crazing and the tiles you installed did, then the customer has a right to be suprised, though.
I was gonna say maybe the installer troweled a "craz-y" pattern in the thinset instead of going all one direction ... which can cause cracks ...
But I've only seen and heard of that on larger tiles .....
Maybe if the smaller tiles were fragile enough?
Jeff
Buck Construction Pittsburgh,PA
Artistry in Carpentry
I spent 15 years as a potter and I know a bit about clay/porcelin and glazes. Crazing is a condition where in the firing of the tile the glaze layer shrinks more than the clay or porcelin. This causes cracking due to the uneven stresses. In some cases this is desireable and planned. Usually when done on purpose, the cracks are stained a darker color to highlight the cracks and perhaps refired to seal it in. The extra steps involved make for the added expense. If the tile formed the cracks after being installed I doubt that it was suppose to. It's most likely caused by one of two things.
1.The glaze fit was wrong for the tile. This can show up years after the making of the tile. Caused by a badly formulated glaze or a change in the composition of the glaze chemicals.(Being natural materials, the chemicals need to adjusted regularly in a manufactuing due to changes in the mine run.)
2. The clay is not fired to a high enough temperature and is still able to soak up water. This causes the clay to swell and cracking the glaze layer.
That was probably more than you wanted to know, but it sounds to me like it was defective tile and the sales guy is blowing smoke.