I've been thinking about insulating hives from underneath as well as on top this winter. Seems like it might be counterproductive to simply set hives on top of insulation, though. For one thing, moisture would probably get between the two.
I fished a life raft out of a dumpster yesterday. Not a beach toy, the real thing. It had been slashed to make it unusable, but I cut some pieces from it's floor. The material is a very tough sandwich with vinylized polyester on the bottom, a thin foam core in the middle, and an aluminized reflective layer on top.
Seems like pieces cut to fit inside the floors of hives would block moisture and reflect heat. It's only about 1/8 of an inch thick, so it would still leave an adequate bee space under the frames.
Any thoughts before I kill yet more hives with well-intentioned stupidity?