Baltic/Russian Birch plywood is the only kind I'm aware of that is all birch. It's of very high quality (more plies, heavier, very stable), and is preferred by cabinet makers. Depending on where you are, it can be gotten in 4' x 8' (122 cm x 244 cm) or 5' x 5' (152.5 cm x 152.5 cm) sheets (the latter is more common). As a rule, I don't like to cite vendors as sources, but in this case there's a lot of good information about it. Ultimate Guide to Baltic Birch Plywood
I used (B/BB) ¾" (18mm) x 5' x 5' sheets, which got me a little bigger enclosure with fewer cuts (I don't have a table saw). I also designed the enclosure around the 24" x 12" (nom.) tiles (cuz I don't have a tile saw/cutter either :roll: ). Finished size is 61.5"W x 25.75"D x 36"H (including a 9"H compartment for lighting, electrical, & storage). It sits on a 72"L folding table.
Whatever kind of birch plywood you decide on, I would strongly urge you to seal it. :laughing6:
You will thank yourself later. I used a triple-thick water-based urethane (I used the same # of coats as regular urethane), but there are many other good reptile-safe products. Curing time is dependent on a number of factors (temp, humidity, etc.); this stuff took about a week after the final coat, IIRC.
The best plywood in the world will still be affected by moisture/humidity. If it gets wet, it may raise, swell, and/or buckle the grain. If too dry (from warmer than room temp and low humidity) the veneer may still shrink or crack over time. Unsealed plywood will also absorb liquid & odors from dragon droppin's, and the liquid from which can still trickle down between tiles--even with a moisture barrier under the tiles. ? happens. :laughing6: I might not have believed it had it not happened to me personally, but somehow ZARDOZ managed to poop right on the wall. I was very glad I had sealed that plywood; it cleaned up easily with Nature's Miracle for Stinky Dragons, except for an unfinished strip I had used as a spacer between tile & wall. I had to replace that. (PEW!) :wink: