Hi Lloyd
Sorry about the delay in replying...Massive computer crash!

My hives would come under your description of "tight", no gaps, no extra
entrances, no deliberate ventilation, there are significant differences in
construction to what many consider is "standard".

I live un the UK Midlands...The overwhelming hive standard here is the B.S.
National.

As the proprietor of APEX ENTERPRISES I conducted many experiments in
equipment design.

I used to keep bees on the roof of the seven story building that my factory
was part of, very windy and as cold as it gets in the UK...One winter storm
not only blew off several 10" deep, heavily built roofs and scattered crown
boards (inner covers) and ekes over a wide area. But some of the parts were
blown so far away that they were never recovered.

A quick re-think was called for...and this is what I came up with.
My hives are top bee space (normal National equipment is bottom bee space) I
decided to make some roofs that were the same size as the hive (no overhang)
these roofs consisted of a 460mm square of 9mm plywood, a 50mm deep rim, a
50mm thick expanded polystyrene insulation block, this was finished off with
a 460mm square thin ply top finally covered by a galvanised steel top skin.
With this form of roof there was no need for an inner cover and to hold it
in place I used stainless steel "Z" clips (available from the appliance
trade). No provision was made for ventilation other than the entrance (the
lowest point).

That was all twenty years ago I have used that system on about 80 hives, in
a dozen different apiaries, and have not noticed any condensation. Prior to
using this insulated roof I regularly noticed condensation on the crownboard
and occasionally mould growth.

The insulated top distorts the winter cluster into more of a carrot
shape...I feel this broader top gives the bees better access to winter
stores at the coldest time of the year.

Having said all that about winter, the summer poses no problems either...the
bees ventilate the hive by fanning inside the entrance in just the same way
as hives with more conventional roofs.

Best Regards, Dave Cushman
G8MZY
Email: [log in to unmask]
Website...Beekeeping and Bee Breeding
http://website.lineone.net/~dave.cushman