top ventilation I guess would have been vital, to allow circulation of air and to stop dampness.
Hi Jeff, (and for any new beeks who might like to get an idea of recent changes for the better)
It was considered vital by many, yes. The top insulation has long been used, but, I fear was fairly inadequate when considering the 'dampness' stakes.
When I started, a few layers of newspaper or a couple carpet tiles was the order of the winter insulation. While clearly better than nothing, it did not prevent a damp hive in the depths of winter. My mentor accepted some damp and mouldy comb, in spring-time, as normal.
As a new beek I had trouble getting my head around the apparent art of arranging the right amount of ventilation required. I very quickly grabbed the 'new fangled' open mesh floor idea (it was touted as a 'varroa' floor by the advertising hype type, but it didn't need much to spot it was not the revelation claimed in that department, but did offer an alternative hive ventilation system with no(?) drawbacks and and (independently) reported huge improvements in over-wintering.
So I tried one of my four home colonies on an OMF and it worked. Colony went through in good shape and no dampness problem at all. So they got changed in fairly quick time.
I reasoned that heat loss was a major winter problem as most of the consumed stores were carbohydrate and the bees were not exactly running around using up energy, so I insulated heavily (I still have some of the 100mm blocks of polystyrene that I jammed into a super for covering each hive crownboard). After all, if it wasn't going out downwards through the OMF, it must be going upwards.
Some local association members looked on my 'efforts' as somewhat unnecessary and even cranky (I changed to 14 x12 and to top bee space as well - for related and other reasons). They even told me so - that I was out on a limb with kit that was 'different to the norm' and that the urge to try out these non-mainstream ideas would pass.
How wrong they were. Many have now adopted the OMF and top insulate more effectively (most have even left out the matchsticks!) and admit that 14 x 12 is an alternative format to a brood and a half. Only the recent newbies with Langstroths (who feel a bit 'out on a limb' with them) are using top bee space, I think.
I do realise that the bees do not need the whole area of a complete OMF floor for ventilation and that the 'Harding floor' is likely a very good compromise, but I don't prevent them brooding higher in the boxes in spring, so spring build-up is less compromised by the mesh floor, in my hives, than for single deep boxes.
All these changes were not my revolutionary inventions, but progress by simply observing the facts and comparing timber hives with polystyrene equivalents. At times times I feel like I should have converted to poly-Langstroth a long time ago, as my timber hives + insulation now more closely resemble, or emulate, the polys. But the timber ones are still good and can compare favourably with the polyhives, as long as the insulation cladding is applied proficiently - but sooo much simpler to buy good poly these days! (and lighter and in National format).
I agree with much of that which Polyhive pushes out re poly, apart from his dislike of one supplier. And Finman has had the benefit of them in much harsher winter conditions than we have to endure in the UK, and writes far more sense than some, on the matter. Somehow, I don't think he includes all of us when the says quote: You British will never learn insulation, ventilation, dew point, condensation, heat production of the bees. Carry on like you have done millions of years. and, of course, he is wrong with the time-scale!!
How long have you been keeping bees? I am guessing at 5 -10 years? You seem to me to be a thinking beekeeper.
Regards, RAB
i understand there may be a bit of extra effort/energy spent if a feed hole is open, and that energy could be used to increase yield maybe, but as I am not commercial and only have 2 hives (well, 4 at the moment), and I get no issue with brace comb, I am happy to let the bees clean up comb which I can then immediately render down. 
Is that millimeters or inches?????
