I put in a call for suggestions for posts on our Facebook page (I just got in from work and am two drinks in and too tired right now to do a whole link thing. Look up dollygrippery on FB) One of the requests was for what materials are used for dance floor by different Dolly Grips. First, I'll go into a little history. When I started, we used birch plywood and luan (yes, luan as a top layer). We would lay it out and screw it to the plywood with one inch screws. As you can imagine, it cracked and popped and didn't work well at all but it was what we had. Later on, someone discovered plastic polymer sheets as a topper over the birch (birch is the ubiquitous plywood used in dance floor. It's all I remember as a young set grip). These sheets were the game changer. They were flexible and quiet, and durable. Now there are two types of plastic toppers used: ABS and Sintra. We use 1/4". Which one you use is really up to you. I've used both, and really don't see(or care) about the advantages of one over the other. It's a plastic sheet. ABS is more rigid and sometimes has a pebbled surface on one side. Sintra is more flexible which makes it easier to get into small spaces. I tend to use Sintra more mainly because that is what my best boy orders and I don't really care as long as it's square and the edges are smooth. I tend to not be too picky about which material I use. They both have their strengths.
The bottom layer is a little trickier. For years, as I mentioned before, birch was the go-to choice for plywood. It's straight and smooth and relatively light. Everyone used it for years. Then it all fell apart (literally) I noticed it around 2006 when I did a movie in New England. After about two weeks, the birch we had started bowing. Then it started falling apart. It was later explained to me that most birch found in the US was low quality Chinese made birch. So we began the search for a better plywood. What we found was Baltic Birch. Plywood from The Motherland. Heavy as hell but it kept it's shape and worked well. Later on and for the last few years, I've used Red Oak. On the show I'm on now, though, we were assured that the birch was American and not likely to fall apart like my last experience. So far that seems to be the case three weeks in. Anyway, there's my short answer to the question. Thanks for asking!
For those of my friends not in the business, a "dance floor" is merely a slang term for a plywood surface laid on an existing floor to give a smooth camera move in more than one direction, unlike track.