NOVA: What kind of analysis goes into figuring out how to demolish a building?
SL: Well, we've got what we refer to as our historic database, which is largely in my father and my uncle's brain. Ninety-five percent of our knowledge has come from hands-on experience—learning, watching different structures, watching the way they move. A lot of times my father and my uncle will walk in a building and they'll say, "Oh, this is just like the such and such building. This is what we're going to do." So, there really isn't a class you can take. There's no book you can read that's going to teach you how to do this. It's really a practical physical understanding of how buildings work. You know, just because an engineer designed a building to work one way, it doesn't mean that, when they built it, that that's actually how it's working. We have to go in and decide what is load bearing, what is not—what is safe to remove, what isn't. So there's quite a bit of in-the-field analysis that goes on.
NOVA: Do you tend to look at blueprints?
SL: Well, 90 percent of the time we don't have them. A lot of times those plans have been misplaced or have disintegrated into dust. But when we do have them, yeah, we use them but we don't rely on them. There's a difference between 'as drawn' and 'as built'. And you never trust the drawings. That's why we do test shots, which is going in and picking out a few key columns and actually loading them with explosives and shooting them ahead of time, to understand the loads within the columns.