I finally managed to use the excess memory foam I bought years ago. It became a porous foam gasket between my 5-sided slip-on insulating box and a lip screwed into my bottom board. I can see the foam accumulating water, like a sponge, for the bees while providing a water vapor gate out while wind blocking.
But I also need ideas. I have a 22 ft. fiberglass sailboat hull ( swing keel) that I decommissioned What can I do with it related to beekeeping. I intend to sink it, dig a hole, in my vernal pool to provide a year round deep spot for fish, frogs,etc. if I cannot find an alternative.