Frederick M. Hueston, PhD

It is strange how events can help you solve a problem. There’s an old saying: “When you least expect it, expect it.” This was so true today when I was asked to explain a limestone pool deck that was falling apart.

 I was sitting next to the Admiral enjoying my morning cup of joe when I heard this loud “boom” of sound. I turned around on my stool and saw it was not just raining, I mean it was pouring.  It was so loud Flo had dropped the coffee pot, which exploded and went all over the floor. The entire diner erupted in a round of applause. The Admiral turned to me and said, “I think my wife is starting to get depressed with all this rain we’re getting. Every day, I see her at the window with a sad look on her face. If it gets any worse, I might have to let her back inside. Haw haw haw!”  

Flo rolled her eyes and continued to clean up the coffee mess. I just smiled and was about to fire back with, “If you want to build an ark, I Noah a guy…” LOL!  But I wasn’t going to wait for him to fire back with another dad joke, so I grabbed my umbrella and headed out the door.

I was fumbling for my keys to the old Woody and dropped them in a puddle by the door. I reached in the puddle and yuck – the keys had a slimy residue on them. I didn’t think anything more of it then, but later that day it would prove to be a clue to yet another stone dilemma.

I finally got in the car when my phone rang. The voice on the other end was a soft-spoken lady. She identified herself as an attorney and told me she had a client who had a large pool deck made out of limestone, and it was flaking and falling apart. She went on to say that they are contemplating suing the designer due to obviously poor-quality stone. I almost broke out in my “there is no such thing as a poor-quality stone since its made by nature” lecture, but I held back and let her go on. She asked if I could schedule a day and time to go out and take a look at it. I told her this afternoon would work.

I arrived at a huge estate. It was so large I thought I would need a map to navigate my way around. Fortunately, I was greeted by a gentleman who identified himself as the caretaker. I so wanted to ask him who owned this enormous tax write-off, but maybe that wasn’t the most professional way to get started. 

He led me to around back to the pool deck surrounding a huge, Olympic-sized pool. The deck was made of large format limestone pavers. There were also several walkways leading from the driveway and the back of the home to the deck. 

As I walked around I also noted that many of the pavers were spalled and flaking. Just as I was about to bend down and take a closer look, a large clap of thunder almost caused me to drop my phone. A second later it started to pour. We all ran under a covered porch waiting for the rain to stop. As I was standing there, I noted that the covered porch had the same limestone but was in perfect condition. I also noted that the rain was not flowing onto the porch. Suddenly, I had one of those “Aha!” moments. I told the attorney that I had all I needed, and I was going to check out a few things before I got back to her. Of course, I covered all my bases and asked all the basic chemical-investigation questions such as the type of cleaner they used, was it power washed, etcetera.

Later that afternoon I was sitting at my office, and I logged on to see the several weather reports that I often check. I found a site that monitors acid rain in that town. Lo and behold – when I saw the pH of the rain I had my answer. The average pH of rain over the last four years has been anywhere from 4.2-5.1. Any pH under 5.1 is considered to be acid rain.  So, if you know that limestone is sensitive to acid, then it is logical to conclude that acid rain was causing the decay of the stone. I called the attorney and gave her my report. Now all she has to do is successfully sue Mother Nature for her client to get a new pool deck. Another case solved.


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. Fred has also been writing for the Slippery Rock Gazette for over 20 years. 

Send your comments to fhueston@stoneforensics.com.