Frederick M. Hueston, PhD

It was a typical Monday. I had just woken up after a long trip to Cali. and had to review a report and laboratory results from a recent inspection. Little did I know that the lab results would prove me wrong  — or should I say right.

It all started when I was hired to look at a problem occurring with a large granite sign erected outside a major movie studio in L.A. . The problem was streaking on the sign where the letters were engraved into it. The streaking was somewhat of a mystery since the sign was in a locale where it wasn’t subject to graffiti, and the sign was old. I would post a picture, but I signed a non-disclosure, and  plus, I have been sworn to secrecy and I don’t want to ruin my chance of being a movie star…LOL! 

I thought this would be an easy inspection, an open and shut case, but it turns out it wasn’t as easy as I thought.

The call I received was your basic, “I have a problem with some streaking” complaint. I have seen streaking issues on many projects over the years, and all of them have pretty simple solutions. They are all rather simple. The wrong grout with a high lime content is a common streaking problem on exterior stone facades and signs, etc.  I thought I could solve this one over the phone with some pics, but they insisted that I come out to L.A. to see this problem with my own eyes. Well, who was I to argue – plus, it could be my big break in becoming an actor – maybe I would be “discovered” like Harrison Ford! Yeah, fat chance, but they were willing to pay my fee and my expenses, so off I jetted to La-La Land.

I drove to the studio and sure enough, there was this large sign about 30 feet or so in the air. From the ground it was clear that there was a streaking problem. I had asked the guy who hired me to have a high lift available so I could get a closer look. There was no high lift at the site, so I pulled out a pair of binoculars to get a closer look. Just as I was deep in my inspection, I felt a tap on my shoulder which caused me to jump and drop my binoculars. Luckily, I had the strap around my neck. 

 I quickly turned around and was face-to-face with a gentleman who I swore was a famous Hollywood director. Darn, I thought – I should have brought my audition tapes. 

Well, it turned out he was just the studio’s engineer and just happened to look like a famous director. (OK, I’ll give you a hint: His recent movie was the last in a series of space-adventure movies. Sorry, you’ll have to guess.)

Anyway, he told me that they had hired a major engineering firm to come out and take a look. They had generated a report, which he handed me, along with the N.D.. Holy crap, I thought as he handed me the “report”. It had to weigh 5 pounds and was in a 4-inch thick binder. Well, I wasn’t going to sit there and go through the entire report. I told him I would review it on the return trip home. (Which I didn’t do, since I fell asleep on the plane.)

However, I did what any sane detective in a hurry would do: turn to the last page or two to see what their conclusion was. Based on their test results, they had summarized that the streaking was caused by the silicone used to surround the acrylic lettering. I just looked up at the sign and then over to Mr. Hollywood.

 I asked the following questions, and got the following answers:

How old was the sign?  Seven years old.

When did you first notice the streaking?  One year ago.

Has the silicone caulking around the letters been changed? No, it’s the original caulking.

 I pointed to the top of the sign where a few pigeons were perched and said, “I see there’s not a lot of pigeon excrement on the sign. How often do they clean the sign?” He told me it gets cleaned every night, since there appears to be a real issue with the pigeons.  I next asked him what they used to clean the sign, and he told me he could find out.

Long story short: I finished my inspection and returned home the next day. 

Now, back to today. I opened the report, poured a cup of tea (Yeah, I know –I’m cutting back) and sat down to review the huge report. Before I opened the binder, I turned on my computer and found an email from Mr. Hollywood with an attachment of the cleaner they used. I did a Google search and discovered the cleaner was a brand-name, highly alkaline cleaner with a pH of 12.  After several cups of tea and my review of the lab report, I had an answer. 

I concluded that the streaking was not from the silicone.  If that was the case, then why did they detect silicone in the testing?  The answer is simple: the trace of silicone was from a sealer they used to seal the stone. I had uncovered this clue after calling and asking if the sign had ever been sealed, and with what. 

So I concluded the streaking was actually residue from the  cleaner.  This is a part of a lesson I now teach my students: Laboratory results don’t necessarily solve the problem. You have to combine the field experience with the test results to see if it makes sense. It this case, it didn’t. Asking the right questions was the key. 

Hopefully, I impressed Mr. Hollywood with my sleuthing, and he can get me an audition! (Hard-boiled Noir detective movies may make a comeback— you never know!)


For more details and to learn more about the investigation process, you’ll have to attend my inspection and troubleshooting class — next session is in Vegas, January-27-30, 2020. Call to register: 321-514-6845.


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 for over 20 years. Send your comments to fhueston@stoneforensics.com.