Interstitial Spaces

Beyond the Surface in a Masonry Mural Deconstruction and Reconstruction

I often ask people questions, not because I need an answer, but to see if they understand what I'm talking about. There's a saying that it's better to stay quiet and seem foolish than to speak up and prove it. For me, it's often better to stay quiet than to confuse everyone. Recently, I spoke up about "interstitial spaces," and here’s what happened.

I sometimes take things apart and occasionally put them back together. If I know I’ll have to reassemble something, I prefer to be the one who took it apart. Even with careful records, some subtle information is always lost during deconstruction. This lost information is always valuable and sometimes crucial for putting things back together.

I was asked to look at a terra cotta mural in a building lobby that Volvo had owned and sold. The goal was to figure out the cost to remove and move the mural. The mural wasn't flat like a tile; it was made of individual, three-dimensional terra cotta blocks. As a masonry structure, you could compare it to a stone wall where the individual pieces aren't flat. The mural was actually curved inward and made of separate vertical panels. It showed an abstract image of a Norse ship at sea with a large sun. I didn't know who the artist was or where it came from. We assumed it was made in Sweden and then shipped to the U.S. for installation.

I'm always curious about how things are made. The idea that it was made in Sweden suggests that the terra cotta pieces were likely laid out in a workshop, and the pottery was made to fit a specific design and size. This also implies there must have been a way to keep track of the layout, take it apart, pack it for shipping, and then communicate this information to whoever was going to put it back together. There might have been photos, individual pieces were probably labeled, and there were likely overall measurements for the wall space it would fill.

With jobs like this, there’s always a question of what’s authentic. When would we be asked to reconstruct the mural? Would it be to perfectly copy how the mural was laid out in the Swedish workshop, trying to guess the original artist's unknown intentions? That's pretty unlikely. Or would it be to rebuild it exactly as it was installed in the Volvo lobby?

When I stood looking at the mural, I noticed some differences in how the pieces and panels fit together. This told me that the person or people who put the mural together had made decisions as they went. The top of one panel didn't line up with the one next to it by almost an inch. A casual observer wouldn't notice this, but it became a problem for someone asked to move the mural. I then saw other differences, and in my mind, I could picture several small but important decisions that had been made. With enough study, I thought someone could figure out the order in which it was put together.

I asked the conservator if the goal of the reconstruction would be to accurately recreate the exact layout of the terra cotta or to copy the installer's decision-making process. It was clear right away that my question was causing confusion.

From a reconstruction point of view, the difference between these two approaches is very important in terms of effort, time, and cost. Since I was asked to figure out the cost, I needed to know which path we would take.

Thinking back to when I confused people at a conference during a question-and-answer session, I asked about this difference to some people who had worked on moving murals. Either I wasn't clear, which is why I’m writing this now—to try and be clearer—or this was another question where I wasn't looking for an answer so much as trying to see if they understood what I was talking about. Based on their response, I don’t think they had a clue. I see a big difference in how people understand processes: those who just think about taking things apart, and those who actually take things apart, put them back together, and think about what they’re doing.

I got flustered asking my question and suddenly used the word “interstitial.” My wife, who edits these articles, tells me she thinks “interstitial” is a "post-SAT" word. I was trying to explain that the irregular joints between the terra cotta pieces—some going from a quarter-inch to nothing, or being whatever they were, but certainly not regular—meant that the knowledge of these interstitial spaces would be lost once the mural was taken apart. I don’t think any of this helped my case, and I’ve been told before not to use words people don’t understand. Like never using "rheostat" or, even worse, "quim" when playing Scrabble.

The response I got seemed to suggest they would map all the joints. This would make the project very expensive, as first all the joints would need to be mapped precisely, including their angles and how much they stuck out from the wall. Then, during reconstruction, it might take several hours per masonry unit to set each one exactly. Heaven forbid an error was found midway, and the work had to start over. It would need a worker with enough patience to set the units and also enough patience to deal with the inevitable three people looking over their shoulder to make sure the interstitial elements were accurate to the desired goal.

Or, one could do what seemed to have been done before: the worker had some idea of what they were rebuilding, put one piece on another from the box, and when things didn't quite fit, they used their masonry experience to make a decision and keep going because, in the end, no one would notice—except maybe me forty years later.

Curiously, while working on a totally unrelated project, I described the mural to a seismic monitoring technician. He said he once dated the daughter of Volvo’s CEO and that it was quite likely the CEO had commissioned the mural. As it turned out, the project never went beyond us providing a cost. (Many of our more interesting projects never go anywhere.) The mural is still there, not to be moved. We amused ourselves by guessing how many new Volvos we could get for it. I once thought owning a Volvo meant success, but despite my shortcomings, I own a Subaru and a Dodge truck. From this experience, I remembered that for a time on LinkedIn, one of my contacts was an estimator for converting Volvo factories.

But the question of interstitial spaces needs to be asked, and it's better to ask it before the project begins, not in the middle of reconstruction. In the end, when putting together a cost estimate—which always requires understanding the construction logic—we assumed (because my question wasn't understood) that the method would be to Keep It Simple, Stupid (KISS). We would also have a strategy to resist any attempts to make the project more complicated, scholarly, or worthy of being documented in a peer-reviewed journal.

As I often say, do something, say something. But in this case, standing up in a conference and asking that question, I should have stuck to saying something stupid… like my question at a brownstone conference about whether expansive mortars were suitable for historic repointing.