Frederick M. Hueston, PhD

Tile tenting is real and actually not all that uncommon – unfortunately because bad installations are not all that uncommon. You can see a video of this phenomenon happening on YouTube – search for “tile tenting.”

Tile tenting is real and actually not all that uncommon – unfortunately because bad installations are not all that uncommon. You can see a video of this phenomenon happening on YouTube – search for “tile tenting.”  
Tile tenting can happen to granite, marble or porcelain tile flooring. Sometimes it is not even the installer’s fault – but most often, it is. I examined four clues to determine whether this failure was a poor installation – and you can learn how, in my upcoming class.

Tile tenting can happen to granite, marble or porcelain tile flooring. Sometimes it is not even the installer’s fault – but most often, it is.

I examined four clues to determine whether this failure was a poor installation – and you can learn how, in my upcoming class.

 

I have been in the stone business now for nearly 40 years, and I thought I had heard it all until this new case came up.

I was having a cup of joe at my favorite greasy spoon, trying to jolt my brain into action, when my phone rang. “Stone Detective,” I answered in a hoarse voice. The lady on the other end of the line starting telling me how her new floor was acting wierd. Now, my first reaction was that this old man was losing his hearing. She continued on and on about how several times at night she keeps hearing a loud bang, like someone was shooting a gun.  At first she told me she thought someone was banging on the door, but she told me she thought it was coming from her floor. Now, I had a good idea what was going on, but I had to do an inspection to find out for sure. I arranged to see the floor the next day.

As I pulled up to the victim’s house, a large lady came running out screaming, “It’s doing it again! It’s doing it again!” I rushed into the house while turning my phone camera on, in hopes of catching it on video. I heard a loud pop as I entered the door, but was unable to catch it on the camera. However, later that evening, I did find a video where someone else had captured it. 

The tile was a white porcelain, and the first thing I noticed was the very tight grout joints. This was clue number one. I took out my old Acoustic Sounding Device (a golf ball) and started bouncing it on the floor. I immediately noticed that the entire floor was hollow. The area was fairly large. I would say the living room alone had a span of over 20 feet. I looked carefully at each and every joint and could not find one expansion joint (clue # two). I asked the scared lady if I could remove a baseboard and she agreed. I pulled off a short baseboard and noticed that the tile had been set right up against the wall (clue # three).

I continued my inspection when the lady asked me to come into the dining room. When I entered the dining room the first thing I noticed was that the tile had tented right in the middle of the floor (clue # four). 

These are all clues for an improper installation. In addition to the lack of bonding, there were no expansion joints or perimeter joints. I explained to her that all tile installation contracts and expands, and if you don’t allow for this expansion something has got to give. In this case, the walls were expanding onto the tile and causing the tile to push up. The loud bang sound she was hearing was the tiles breaking away from the concrete slab. Even when the proper bonding is achieved, the tiles can tent due to the pressure.

Now for you tile nerds or those taking my troubleshooting class, here is a more scientific explanation.

Tile in general has a different rate of expansion, compared to the concrete slab it is set over. The expansion and contraction rate of concrete can be ten times higher than the tile. What this means is that a slab 100 feet wide can expand as much as half an inch. While that doesn’t sound like a lot, it only takes slight pressure to pop the tiles off the concrete. For this reason, expansion joints are critical. If the room is small enough, expansion joints wont be needed in the main field of the installation, but you will need perimeter joints. In other words, there should be a gap around the perimeter of the room at least one-eighth inch wide. This will allow for expansion.  If you would like to learn more I would suggest you attend my inspection and troubleshooting class coming up in January 2019. (I know  – another shameless plug.)

I told Mrs. Hysteria the bad news: the floor would need to be ripped out and replaced, and I thought she was going to faint. I sure don’t enjoy causing mental anguish, but facts are facts, and there’s no mistaking tented tile. Another case solved in record time. 


The Stone Detective is a fictional character created by Dr. Frederick M. Hueston, PhD, written to entertain and educate. Dr. Fred has written over 33 books on stone and tile installations, fabrication and restoration and also serves as an expert for many legal cases across the world. Send your email comments to him at fhueston@stone forensics.com.