My next little tablesaw/woodworking project: clear, insulated crownboards for beehives. More box joints for these, to make up a box about 60mm deep. Then a sheet of clear polycarbonate on the bottom, held in place around the sides by a 10mm wooden strip, giving a bee-space over the tops of the frames below.
Into that goes a piece of 50mm thick PIR insulation board (commonly found in skips apparently, though I had some left over from a building project), with a little handle glued on.
And the roof will go over the top completely.
The insulation stops condensation forming on the underside of the crownboard where it can drip down onto the bees, meaning there’s no top ventilation required to remove it. Any condensation on the hive walls can be re-used by the bees for diluting honey. It also helps the bees keep the humidity up inside the hive, which allegedly helps with varroa.
In retrospect, I may start making the clear crownboards with a 10mm rim on both sides and then fitting the insulation into the roofs when I build them. That may be slightly more efficient and use less materials.