Wintering bees in the U.K.

[ericbeaumont]

clear acrylic sheet crownboard (top beespace) and a poly roof (and even with extra pir under the poly roof)

Is the PIR in full contact with the acrylic CB?

 

[Sutty]

Is the PIR in full contact with the acrylic CB?

Yes

 

[pargyle]

I was talking to Derek and Elaine at the National Honey show .. what they are doing now is putting a thin sheet of correx (the thin stuff that contractors use to protect surfaces) immediately on top of the top bars - the bees propolise it in place - then a crown board with a rim and then top insulation. The air gap between the correx and the crown board provides excellent insulation as it is static air. That and insulation above the crownboard ..

He's been working on convection currents in the hive and the correx, immediately on top of the frame, effectively stops this.

I've probably explained it a bit simpler than Derek would but you get the gist of it. Hopefully he will come back with the proper science at some point.

 

[Sutty]

I was talking to Derek and Elaine at the National Honey show .. what they are doing now is putting a thin sheet of correx (the thin stuff that contractors use to protect surfaces) immediately on top of the top bars - the bees propolise it in place - then a crown board with a rim and then top insulation. The air gap between the correx and the crown board provides excellent insulation as it is static air. That and insulation above the crownboard ..

He's been working on convection currents in the hive and the correx, immediately on top of the frame, effectively stops this.

I've probably explained it a bit simpler than Derek would but you get the gist of it. Hopefully he will come back with the proper science at some point.

This would reduce the bees mobility over the top bars to access fondant or syrup, on the other hand in an adequately provisioned natural nest there would be no top void to bridge combs......

 

[robmort]

This would reduce the bees mobility over the top bars to access fondant or syrup,.

I agree and don't see the need for the correx if you have insulation anyway over the crown board. With a perspex crown board you want to see the bees beneath and how they are moving across the frames, after you lift the insulation.

 

[JamezF]

I agree and don't see the need for the correx if you have insulation anyway over the crown board.

I'd guess it's because the gaps over the top bars allow convection currents to form such that heat rises from the cluster, moves out towards the walls where it cools and sinks down the walls, reinforcing the cycle. Closing the gaps may not stop that completely, but it might reduce it significantly, thereby making it easier for the bees to maintain the temperature of the cluster and/or the brood nest.

I really am guessing though. Thermodynamics isn't really my thing and can become hideously complex.

James

 

[Erichalfbee]

Is the PIR in full contact with the acrylic CB?

I think I remember Derek saying the gap between a rimmed crown board and top insulation didn't matter

 

[Newbeeneil]

I think I remember Derek saying the gap between a rimmed crown board and top insulation didn't matter

In fact I made a crownboard out of correx after that conversation. It seems to have performed well this season.

 

[robmort]

I'd guess it's because the gaps over the top bars allow convection currents to form such that heat rises from the cluster, moves out towards the walls where it cools and sinks down the walls, reinforcing the cycle.

Doesn't stop any such convection currents along the frames, which would be reinforced.

 

[madasafish]

I place clear plastic sheeting (think Clingfilm) on the top bars of mini nucs and weak poly/wooden nucs/hives which I am feeding. Feed goes on topbars under clear film.
Advantages: : you can remove roof and see what is happening/state of feed w/o any disturbance of bees.
Started doing it in 2018 when I started overwintering mini nucs.. No condensation visible Photo of double brood Kieler overwintered successfully for three years.

 

[JamezF]

Doesn't stop any such convection currents along the frames, which would be reinforced.

In theory, no, it doesn't. Whether it does in practice given that the seams are full of bees, I really don't know.

James

 

[ericbeaumont]

clear plastic sheeting

Yes, thick plastic works well as an emergency CB, though of course, sometimes it will remain on all year round, and without any condensation. I have noticed that bees modulate air movement between top bar and sheet using wax and propolis along sections of both top bar edges. The sheet edge is always glued down.

I don't use clingfilm because one year I found bees chew and drag it easily, and I found bees with fragments stuck between abdominal tergites; it was impossible to remove. Compost bags are thick and make good CBs.

 

[pargyle]

I must admit that my bees build brace comb between the clear crownboard (which has a 6mm rim for top bee space) along the top and joining the bars to the crownboard. Talking to Derek - his explanation - they don't want space above the frames which permits convection so they try and block off the space to reduce the airflow. I can see the logic in this - if you think about it - in feral nests they attach their combs to the top of whatever cavity they decide is home and they don't leave top bee space.

I like my clear crown boards that provide top beespace for all sorts of reasons but ... am I doing my bees a disservice ? If Derek is right about in-hive convection (and I suspect his science is spot on) then I need to think about this - what is convenient for the beekeeper may not be as convenient for the bees.

 

[Gilberdyke John]

I should mention that I've been obsessive since 1957

Isn't there treatment for obsessive compulsive disorder?

 

[Mint Bee]

Am I missing the point here? As Corex is corrugated, isn't the CB made of this going to in direct contact with outside air through the groves in the construction?

 

[Sutty]

Am I missing the point here? As Corex is corrugated, isn't the CB made of this going to in direct contact with outside air through the groves in the construction?

I thought this too, I suppose a strip of duct tape or similar over the edge would seal off the cavities.

 

[JamezF]

Am I missing the point here? As Corex is corrugated, isn't the CB made of this going to in direct contact with outside air through the groves in the construction?

Could be that he's running TBS hives, so the correx sits inside the top of the box? That might make it a pig to remove though. Or the correx could be sized to fit inside the bottom rebate of the crown board perhaps, so its edges aren't exposed externally.

James

 

[JamezF]

Another issue may be that with the bees unable to access the real crownboard because of the correx, they'd not be able to propolise it down and seal it for the Winter.

James

 

[Murox]

I've been using old political signage, so correx board as crown boards for a couple of years, no rims just straight on top. No particular problems noticed. I just put on a wooden one when I use syrup as they have a hole already.

 

[GaryH]

Google interstitial condensation and warm roof cold roof theory. This relates to building but the physics are the same.