I was just watching a 'Stewart from the Norfolk Honey Company' video and he was looking at winter bees by taking the top off and peering through the transparent, plastic cover. He said he wasn't going to look at the wooden hives because he didn't want to expose the bees by removing the crown board and letting the heat out...which brings me to my point.
Just because the hive is wooden, why, in general, do we use wooden crown boards rather than just use transparent covers. Surely using the latter we could have a look at the colonies in all weathers without disturbing the bees? Is it because the wooden hives have a larger area therefore the cover would drop onto the frames -- in which case thicker covers would solve that problem -- or is there some other reason for which I haven't accounted?
ive spent some considerable time pondering this very question I watched the video too. When i first started beekeeping i had all my hives with wooden crown boards and nothing else above , no other insulation and they overwintered fine(or what i thought was fine at the time) with our Nicot bases open, (like the standard mesh floor)
As time had progressed ive changed, expanded to having just a plastic sheet with the insulation directly above. Looking at the changes ive made, i would say the reasons are three fold.
One is cost. The cost of a good quality crown board. i didn't have the initial capabilities to make many, and the cost of buying was high, so i jumped to using a plastic sheet!
two: You can ***** the bees as many have found out and seen (as described above) without touching or actually disturbing the wintering cluster. we all love to poke, this satisfies our curiosity in the longest winter months.
three: For me, Stuart Spinks does what he does because he knows if he cracks that crown board, he will completely disturb the bees. Breaking that propolis seal between the two boards. He understands its not good practice when the resulting cluster takes a fair while to settle after being disturbed and it was well below freezing could be the tipping point for a small cluster.
I am not getting in to a deep conversation over thermodynamics of wood versus poly and all the relevant data that exists, there a lot of far more qualified people on this forum who know this better but i will say what ive found it that the poly sheet, Perspex or the cellotex, whatever you use makes things so much easier. You need to insulate above the sheet well. Good standard cheap insulation is best. Styrofoam, Polystyrene or Kingspan are excellent.
And You Dont get humidity collecting if your insulation is correct, why would you!!!!
One of the only downsides with plastic sheets are if you want to flip your crown boards over ( to give more room above the cluster, or for the cluster to move over the top of the frames easier after the flow finished in the autumn) in the late spring to give a feed or a pollen sub you cant. You have to use an eke. which in itself is easy enough but its more material. ( but still cheaper than buying a crown board)
https://youtu.be/PbOGFxfjL44
You only need to look at Mike Palmers overwintering cluster video to see good clusters moving under inverted crown boards to see what i am on about. Mike still has styrofoam above the inverted crown board. I am sure he will have more on this if you ask.