Roof design? Can we have a ponder

[Beeline]

What about vacuum forming? Might be cheaper...

Roche I think you may be thinking what I'm thinking.

uPVC injection moulded lids. Cavity of 50mm could be maintained and later insulation injected into the cavity once the two components are fused together.

Lightweight, provides insulation, weatherproof, woodpecker proof. Could be used all year round.

Downside is min. order required but I suspect there would be many takers depending on RRP.

BL

 

[fatshark]

It is actually as in the winter the poly roof is far preferable to a wooden one.

Having just wrapped my hives for the winter I'm not so sure about this. All get a black plastic fertiliser sack around them to stop woody woodpecker in his tracks. The ply/cedar hives are no problem as the roof is metal-covered. However, the poly roofs are still open to attack (and a poly nuc. has already received some attention). It's a palaver making a mesh screen to cover the poly roof alone and so I'm considering adding a 6" deep cedar roof PLUS kingspan onto the poly hives.

I think a metal cover for a poly roof would be very useful and would add only a small amount of weight.

 

[Poly Hive]

I have to say from the off I have never had wood pecker problems, whether from pure luck or location I cannot say.

Are they going in from the top?

Just sat and mused here as to what I would do myself. Answer is in my mind borrowed from Hamish Robertson who swore by having a "bit of tin around". Cut some corrugated iron to suit, put on roof with some bricks to hold it on, and let them blunt their beaks on that.

PH

 

[drstitson]

not roof - bottom edge of brood box rail.

 

[roche]

Roche I think you may be thinking what I'm thinking.

uPVC injection moulded lids. Cavity of 50mm could be maintained and later insulation injected into the cavity once the two components are fused together.

Lightweight, provides insulation, weatherproof, woodpecker proof. Could be used all year round.

Downside is min. order required but I suspect there would be many takers depending on RRP.

BL

Vacuum forming is much lower cost than injection moulding - the tools are quite different. Bit in general the idea is as you describe...

 

[fatshark]

not roof - bottom edge of brood box rail.

Yes ... a favourite spot if the fertiliser sack is a bit short. The blighters hang onto the hive stand and go for the exposed bits.

Wire mesh 'hairnet' for a P a y n e s nuc.

 

[oliver90owner]

Wire mesh 'hairnet' for a P a y n e s nuc.

Looks good. The smaller the mesh size, the closer to the hive the 'hairnet' can be. OMF sized material could be adjacent to the hive surfaces, as long as the 'pecker could not destroy the covering material.

I have used a large plastic bag to cover a timber hive (fitted below the roof similar to yours, here), after an unsuccessful 'pecker attack) with no damp problems. Probably something to do with using solid crownboards, with insulation over, and an OMF under the brood box.

Newbies should note: not to use bin bags as these may well tear, or develop small holes, which can create a 'damp' problem.

RAB

 

[rae]

You don't need to go nuts on the roof thickness.

If the centre of the cluster is about 30 degrees, and the edge of the cluster is about 15 degrees, then on a cold night the difference between the edge of the cluster and the outside is maybe 25 kelvin.

A beehive roof is about 0.2 sq metres, and only a tiny fraction of that is actually warmed - the bit in the middle. So call it 0.1 sq/metres that is actually warmed.

The R value of 25 mm celotex is 1.1. This effectively how many m2 of area I can maintain at a temperature difference of 1K for 1 watt of power. So to hold my 0.1 sq meters at 15C (delta T of 25), I need 2.27W

Replacing my 25 mm celotex with 100 mm (R value 4.5) I only need 0.5W

When you compare that to a simple wooden roof (R value approx 0.1), then you see that you would need 25W to hold the same temperature.

For many years, bees have managed under wooden roofs - so must be able to generate something like 25W. Putting minimal insulation in chops this to 2.2W and going nuts with the insulation takes it to 0.5W

25mm celotex is all they need.

 

[user 6228]

You don't need to go nuts on the roof thickness.

If the centre of the cluster is about 30 degrees, and the edge of the cluster is about 15 degrees, then on a cold night the difference between the edge of the cluster and the outside is maybe 25 kelvin.

A beehive roof is about 0.2 sq metres, and only a tiny fraction of that is actually warmed - the bit in the middle. So call it 0.1 sq/metres that is actually warmed.

The R value of 25 mm celotex is 1.1. This effectively how many m2 of area I can maintain at a temperature difference of 1K for 1 watt of power. So to hold my 0.1 sq meters at 15C (delta T of 25), I need 2.27W

Replacing my 25 mm celotex with 100 mm (R value 4.5) I only need 0.5W

When you compare that to a simple wooden roof (R value approx 0.1), then you see that you would need 25W to hold the same temperature.

For many years, bees have managed under wooden roofs - so must be able to generate something like 25W. Putting minimal insulation in chops this to 2.2W and going nuts with the insulation takes it to 0.5W

25mm celotex is all they need.

what happens at the sides?

 

[rae]

Same story. Though how much does the cluster warm the sides of the hives? I'd guess the sides are at about 5C, which means very little heat loss.

 

[oliver90owner]

You don't need to go nuts on the roof thickness.

Quite agree. Anything is better than nothing. Condensation may be the bigger enemy than actual heat loss (while the colony is dry).

My newer roofs have 25mm EPS tucked in them all year round and I place another 25mm sheet (460mm square) over the crownboard for the winter. More than enough in my experience (particularly as some say they use none and leave gaping holes in the ceiling).

At the coldest, the bottom outside of the cluster can fall below ten degrees and the bees only heat the cluster, not the hive, so that will reduce the energy required to be generated by the cluster. Heat will still go out the walls and through the OMF (and the entrance on all hives, really). The floor temperature will be close to the outside ambient air temperature at all times, while the bees are clustered a reasonable distance away from it.

 

[Hivemaker.]

The floor temperature will be close to the outside ambient air temperature at all times, while the bees are clustered a reasonable distance away from it.

They often cluster right down onto the floor,unless of course there is a gaping great hole like in a mesh floor.

 

[drstitson]

i didn't think the cluster centre was anything like 30C.

 

[itchyhives]

.........rebuilt a few of my hives roofs over last winter 2"deeper with 50mm kingspan built into the roof (used 50mm as this is what I had). Seems to work very well, have used it through the summer and going into there first winter. Time and space is limited for me this year so to have insulation built in has been good, cutting down on moving stuff around and having to store it in the summer.

 

[Hivemaker.]

I noticed different coloured grp hive roofs for sale on E bay.