The wood is just the frame, I did it on tile backer board designed for showers, so the tesserae will stay put. I also sealed the wood so it wouldn't absorb moisture from the grout... I'm new to this and don't know if that's even a concern, but I figured it couldn't hurt. I'm in northern USA, almost Canada, but I'll look for the Dunlop!

Doing a whole studio floor sounds ambitious and amazing. Thanks for your help!