We have a Dynamo at work we play on. It currently sets in our cafeteria and they are talking about moving it down to what used to be the "smoke shack". This room is covered has walls windows and doors however, I would still say I was outside if I was sitting in the middle of it. The Dynamo playing field is made of what appears to be a 3/4" or 5/8" particle board. If they do move it, we have discussed disassembling it and treating the raw wood and edges with a sealer to prevent any moisture absorbion. The other option was to Gorilla glue some oak ribs to the botom of the playing surface to prevent any warp. Partical board is known for delamination, swelling and warping if it gets wet however with todays glues that they use to put the stuff together with who knows what humidity will or will not do?