True Stories from the Savvy Surveyor   (no kidding!)

3 — Double Duty Dunnage

The following took place on the roof of a historic building on the east coast with my daughter. She is a licensed interior designer, who was assisting me with an architectural survey. I was giving her pointers about the HVAC equipment as we wrapped up a week long project.

"See here Julie? This is called dunnage. See how it spans from here to there with beams so the HVAC equipment is supported up off the roof? See how...  uh...  what the heck?...  Hold on a second Julie. I need to give this a closer look!   (long pause)   Well...  I'll  be  danged!"

There at my finger tips, as I stood next to a dunnage beam was a 1" all-thread bolt fastened to the top of the beam and bolted tight. It extended down through the roof and out of sight. I looked around. There were a few more, maybe 4 altogether, spaced out under the elevated structure.

Julie had no clue why I started dancing on the roof and singing "I figured it out... I figured it out". Hopefully she was not having one of those teenage moments (common only a few years ago) when they think old Dad is weird, and try to distance themselves! Anyway... the previous clue I found the day before was coming together with what we just discovered.


The building was not tall compared to the others but it was a beautiful historic icon built in the 1920s. Inside was a very busy retail store with two retail floors and a full basement. Julie and I started in the basement. Our job was to create drawings of the building, take photos and provide reports as to its condition. Our client wanted to do some major remodeling including some structure changes.

The basement was a challenge with plaster walls, hard ceilings, and numerous small rooms. Did I mention that we had no base building drawings for this building? And so it went for the next few days as we measured walls, drew sketches, took photos, and looked at equipment in.

We steadily worked up through level one and eventually got to level two. Both were mostly sales floors with lots of shoppers. We had to work after store hours when documenting above the ceiling.

Finally it was close to the end of the week and we were anxious to finish. It was after store hours, and I was standing on a ladder near the rear of the sales floor on the second level. I had my 200 lumen flashlight and was inspecting the structure above the dropped ceiling. It was wood framing, which was common for a building this age. But something caught my eye.

Typical Roof DunnageI saw the bottom of a 1" bolt sticking out below some wood ceiling joists. It had a big washer and nut on it and was apparent that it was there to hold something up. I thought this strange so I inspected further but I couldn't see enough to tell what was going on. So I climbed down and walked the room and studied the ceiling to determine if there were any clues of some equipment up there that needed to be supported. Again... nothing. So I moved my ladder and did what I call "ladder yoga" to try to squeeze myself up through ducts and get a better view. Whew! Again... nothing.

So I moved on, but continued to ponder about what I saw, wondering if it was a clue about something important or something stupidly inconsequential. I am one of those guys that ponders a lot. It is quite common for me to wake in the night with my ponderings... and that bolt was definitely on my mind. Only one day remained to complete the job and we still needed to do the roof.

Actually I had done part of the roof survey on the first day. I have always had good success starting up there first. Many times I can get some great overall dimensions that are impossible to get down on the ground. Also it is always prudent to do a thorough "walk around" of the entire job, including the roof.

So when Julie and I went back up there, I was paying closer attention to details because I had since documented all the systems below and was reconciling them with what I was seeing on the roof. It was then that I saw the tops of the bolts fastened to the beam and going down through the roof. It was then that... well you know the story... I broke out into song!

You may be asking yourself "What is so important about some dunnage bolts?" To make is as simple as possible to understand, the roof dunnage was holding up more than the HVAC equipment. It was also holding up the... ahem... ROOF! In all my years, I have never seen this and most likely will never see it again.

Since our client was going to be doing some extensive remodeling, including some structural changes, this information could be very important to them. It was possible that this bolting system was not code compliant.

Whatever the case, with this information, our client was able to deal with the issue early in the project's planning stages and not be caught by surprise during construction.