I woke up at 5 am this morning to a large crash outside my bedroom window. I got up at a bed and opened the drapes and large chunks of ice had fallen off the roof onto my metal shed.

It left a big dent in the roof. I shook my head and wondered why I was still up here in New York State instead of Florida fishing off my boat. Little did I know that later that morning I would receive a call that had to do with ice and snow and a rapidly deteriorating terrazzo floor.

I made my way out of bed, got dressed and headed out the door to fight the snow-covered roads to my office. I no sooner opened the door when the phone rang.

"Mr. Stone Detective, this is Bob with the University. I got your name from someone and we have a major problem with our terrazzo floor." He had one of those scruffy voices and sounded like he smoked several packs of cigarettes a day. Every other word or two I heard a hacking cough.

"Ok," I said, "what kind of problem." He stated that they had terrazzo floors in several buildings which were falling apart. He went on to say that most of the damage was in the entrances to the buildings and some of the steps. I told him I would come out and take a look in about two hours.

I checked the rest of messages and got in the ole' Woody and headed toward the university. But first, I had a craving for a donut and a cup of Jo. I pulled into my favorite donut shop and got out of the car. I noticed several police cars in the parking lot and I kind of chuckled. Must have been a major donut heist in town. Reminded me of a person I know, who was pulled over for making a wrong turn pulling out of a donut shop. When the cop asked him, "Do you know why I stopped you?" he picked up the dozen donuts sitting on the seat next to him and said, "You must have smelled them." He got a ticket.

I arrived at the university and walked up to the building where I was going to meet Bob. It was snowing heavily and there were several people shoveling the sidewalks and spreading de-icing salts there. I walked up the steps and there was this overweight gentleman smoking a cigarette just outside the door. I figured this was Bob.

"You must be the Stone Detective," he said in that smoker's voice. I said I was and he took me inside and pointed to the terrazzo floor.

Now, I have seen a lot of deteriorated stone and terrazzo floors but this one was awful. It was a pitted mess. The marble aggregate was missing in spots and most of the concrete binders were totally gone. I asked him how long it has been this way and he told me it just got worse year after year.

I walked the floor and noticed most of the damage was at the entrance and dissipated as you went down the halls. Well, it didn't take me long to figure this out since I have seen this many times in Northern climates that have snow and ice. You may have guessed it -blame it on the de-icing salts.

I explained to Bob that Rock Salt is Sodium Chloride and when it dries, it re-crystallizes. This crystal entered the pores of the terrazzo or stone and caused the stone to spall and pit. I told him that there are de-icing salts that do not cause this problem. I also told him to look for a de-icer that contains Calcium Magnesium Acetate.

Unfortunately, the terrazzo was so bad that I didn't think it could be repaired, so I recommended replacement and provided him with a source for a safe de-icing salt. It's amazing how much terrazzo, stone and concrete is damaged by using the wrong de-icing salts. Another case solved.

The Stone Detective is a fictional character created by Frederick M. Hueston,PhD, written to be entertaining and educational. Dr. Hueston, is the founder of Stone Forensics (stoneforensics.com), a nationally known stone consulting company, and also the technical director for Stoneandtilepros.com.

He has written over 33 books on stone and tile installations, fabrication and restoration. He also serves as a expert for many legal cases across the world. Email comments to him at fhueston@stoneforensics.com and see his technical overview on natural stone-friendly de-icers on page 35.

")