No products in the cart.
Expert Answers
What is the cause of the Indent Fractures in My Tile?
QUESTION
What is the cause of the Intent Fractures in My Tile? I have a question. We have a ceramic tile floor of 18" tiles installed on cement board over plywood. Many of the tiles have developed indentations going from one tile to another. Most indentations go in a straight line. Some of these lines curve at the ends. Two indentations have cracked downward i.e. I can not feel an upward edge. We have a basement below this floor. My question is simply what is the cause of these indented tiles?ANSWER
ANSWER - Indent fractures normally occur in natural stone, although I have seen it in glazed wall tiles. We normally don't see it in ceramic floor tiles.Normally indent fractures are due to excessive shrinkage in the thin-set mortar or in the mortar bed that can be caused from too thick or too wet or too rich (high ratio of cement to sand) of an application or mortar, and/or due to improper placement of wire reinforcement in the mortar bed (wire should be suspended within the mortar not at the bottom). The fracture is actually a point of tension that causes the tile to crack and widen at the bottom of the tile.
I just heard about a case where the stone was installed over a cementitious backer board that was installed over a wood subfloor, and they say they have indent fractures. They think it has to do with the plywood having been wet and warped when it dried. That doesn't seem reasonable to me, so I would have to investigate that further to see if there is any correlation. They could have more of a defection problem that causes the tile to compress at those points.
I wrote an article about intent fractures a couple of years ago. If you want to read more about it go to our Blog on our website and read the article titled "Shrinkage leads to Indent Fractures in Stone."
