Frederick M. Hueston, PhD  
Stone Care Consultant 

It was one of those fantastic spring mornings as I woke up and saw a cardinal banging his head on my bedroom window door. 

Stupid bird, I thought, and then I thought about all those times in the stone business where I felt like doing the same thing. I just smiled and got my old butt out of bed. I got dressed and headed out the door early to stop by my local greasy spoon to grab a cup of jo.

Before I could even get to the ole Woody, the phone rang. “Stone Detective, here. What can I do for ya?” The voice on the other end sounded like a young woman. She spoke softly; almost too softly at times. I could hardly hear her. She started going on and on about her marble floor that had a crack running across the entire floor.

Typical, I thought, until she told me that the crack disappears and completely goes away, then comes back at times. I stuck my finger in my ear to make sure I had no wax build-up, because I couldn’t believe what I was hearing. I told her to repeat what she just said and this is exactly what she whispered.

“Sometimes there is a crack that goes across the entire width of my foyer and the next day it’s gone.” I thought about asking her if she was on crack, but my curiosity got the best of me and I had to see this, or maybe not see it.

Disappearing floor crack

I asked for her address and told her I would be there as soon as I got done with breakfast. I pulled up to the gated community, looked at the sign on the outside of the development and had to laugh. It said: Shady Oaks. A Gated Community.

The reason I was laughing is on the way over I was sitting at a traffic light and a biker pulled up next to me. On the back of his T-shirt it said, “Sing Sing Prison–A Gated Community.”

Got me thinking that the cost and upkeep of some of these homes must make the owners think they are in prison at times. I pulled up to a huge Georgian-style home.

I rang the doorbell and it was answered by a very petite lady. At first I thought she was a kid but then she spoke, or should I say whispered. “Hi,” she said. “Come on in.”

As I stepped into the home, everything was white. The floor was a white marble, the walls were white, and the furniture was white. Ms. Whisper was also dressed in white. In addition to everything being white, I noticed that the foyer was very wide. It was at least 30 feet across. I stared at the floor looking for signs of a crack, as she explained about this crack appearing and disappearing. I asked where the crack was and she said, “You’re standing on it.”

I looked down and saw nothing at all. Of course, it was sunny outside and my eyes were not quit adjusted to the indoor lighting. I asked if I could walk around.

She said, “Go ahead,” and left the room.

I started walking around the foyer and noticed that the floor appeared a little bouncy. In other words, it moved as you walked across it. I went to the far corner of the foyer and got down on my old, arthritic knee and looked across the floor. Sure enough, I could see a little line that ran it. Now I had an idea exactly what this was.

I yelled for Ms. Whisper and asked if I could go down in the basement to look at what was supporting this floor. She led me down the steps and into the basement. It was kind of dark and I took out my little flashlight.

I shined the light up to the ceiling and my suspicion was correct. There were no supports across the entire 30 foot span.

The wooden 2x6s were way too weak to support the live load of this floor.

So what was she seeing? Why does the crack appear and disappear?

I went back upstairs and explained to her that her floor does not meet the deflection standard and, basically, the floor was bending.

This causes stress in the stone and you see what appears to be a crack.

Technically, this is called a compression crack. When the floor is under compression due to a live load, the tiny stress line appears.

Eventually, if the floor is not corrected, it will develop into a full-blown crack.

I told her she needed to have the floor supported underneath and that should take care of the problem.

Another case solved. Now, I wonder where can I get some lunch?

The Stone Detective is a fictional character created by Fred Hueston, written to be entertaining and educational. He 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. You can send any email comments to him at fhueston@stoneforensics.com