Condensation and Mould - Building regs say...

[user 6228]

From UK Building Regulations part C2 ammended 2010

Roofs (resistance to surface condensation and mould growth)
6.14 A roof will meet the requirement if:
a. it is designed and constructed so that the thermal transmittance (U-value) does not exceed 0.35W/m2K at any point;

External walls (resistance to surface condensation and mould growth)
5.36 An external wall will meet the requirement if:
a. it is designed and constructed so that the thermal transmittance (U-value) does not exceed 0.7W/m2K at any point

If you do the maths these are met by ... 40mm( wall) and 80mm(roof) of polystyrene or 27(wall) and 57mm(roof) of polyurethane foams.

Shouldnt we building our hives to this?

 

[oliver90owner]

Shouldnt we building our hives to this?

No. You missed out the relevant part which considers the floor. So we could say your idea is floored!

 

[Hivemaker.]

From
Shouldnt we building our hives to this?

Look nice topped with some Welsh slate as well.

 

[user 6228]

Look nice topped with some Welsh slate as well.

woodpecker proof as well

 

[user 6228]

Shouldnt we building our hives to this?

No. You missed out the relevant part which considers the floor. So we could say your idea is floored!

best to start at the top and work down - getting people to swallow the two is an achievement.

I also thought you might gag at being able to have a floor that ventilates, allow mites to drop out and meets the thermal constraints. Although its all perfectly possible.

Floors (resistance to surface condensation and mould growth)
4.22 A floor will meet the requirement if:
a. a ground floor is designed and constructed so that the thermal transmittance (U-value) does not exceed 0.7W/m2K at any point;

 

[Erichalfbee]

Look nice topped with some Welsh slate as well.

No no...has to be Cumbrian slate from Honister....comes with a zip wire

 

[Finman]

.
Wear wool shirts on the hives. Those, out of fashion.

I visited in Welsh. There was a village where everything was made from black stone slices.
Windows were perhaps transparent glass. There was a mountain near
village which was a huge heap of those stone slices. They may have beehives made from stone too.

 

[Finman]

.
Wear wool shirts on the hives. Those, out of fashion.

 

[Finman]

.
Mould problem is difficult. It is not barely insulation issue. Structures need ventilating layers and moisture barriers. There is a dew point somewhere in insulation structures. In wrong place styrofoam makes a moisture barrier too, and make the structures wet.

And stryrofoam is very fire sensitive. In houses we use much stone wool and glass wool.

 

[BBG]

.
Wear wool shirts on the hives. Those, out of fashion.

I visited in Welsh. There was a village where everything was made from black stone slices.
Windows were perhaps transparent glass. There was a mountain near
village which was a huge heap of those stone slices. They may have beehives made from stone too.

Blaenau Ffestiniog - pretty grim!

Has a narrow guage railway down to Porthmadog.

Did you visit Port Meirion too.

 

[oliver90owner]

Shouldnt we building our hives to this?

Seems that polyhives are close. Internal temperatures may be lower and there will be less ceiling area per insect (c/f a human dwelling) in a hive, so the regs for thermal insulation for a human dwelling won't be totally relevant for a beehive.

Human dwellings are clearly oversized and/or would likely suffer from condensation if one were to cram the dwelling full of bodies like a beehive. Bees cluster at a surface temperature, not a great deal in excess of 8 degrees at times; not too comfortable for most of the first-world human population, I would suggest.

As beehives have for years been 19mm timber and many beekeepers have left relatively huge openings in the ceilings, it would appear that the bees can tolerate far different conditions than those specified for human habitation.

Of course, these specifications are only for new-builds and much of the old housing stock survives quite well while being constructed to a lower specification, or indeed, no specification at all.

There is however no good reason for not striving for the best for the bees, if only from the economy of stores-usage, to heat the home throughout the winter (ignoring the fact that the bees only really heat 'the cluster' and not the hive).

Indeed, there are some here that advocate condensation in a beehive, as good, for the bees to utilise their stores. Not something I particularly subscribe to, but another consideration for some (even the OP, perhaps?).

 

[user 6228]

Shouldnt we building our hives to this?

(ignoring the fact that the bees only really heat 'the cluster' and not the hive).

....

my bees are ignoring that fact at the moment keepingl peripheral area at a constant 18c regardless of outside temp or amount of brood

 

[oliver90owner]

my bees are ignoring that fact at the moment keepingl peripheral area at a constant 18c regardless of outside temp or amount of brood

Not really! The brood nest needs to be around 35 degrees, if there is open brood. So the bees are 'heating the brood nest' and not the hive? One would always expect there to be thermal energy transfer from warmer to cooler; one would always expect there to be convection flow with fluids and a temperature gradient. So nothing remarkable about the 18 degrees you are recording?

 

[user 6228]

my bees are ignoring that fact at the moment keepingl peripheral area at a constant 18c regardless of outside temp or amount of brood

Not really! The brood nest needs to be around 35 degrees, if there is open brood. So the bees are 'heating the brood nest' and not the hive? One would always expect there to be thermal energy transfer from warmer to cooler; one would always expect there to be convection flow with fluids and a temperature gradient. So nothing remarkable about the 18 degrees you are recording?

err its doesnt work like that. you cant get a constant temp at fixed point like that.
On a gradient of 35C to ambient at some point you get 18C. Change ambient temperature the location of the 18C point moves.
And Bees can heat more than one location at more than one temp.... Cite the paper if you likes

 

[oliver90owner]

Cite the paper if you likes

No need to bother. The bees will still heat the cluster and anything else will simply follow.

Heat transfer to the surroundiings is inevitable if they are at a lower temperature than the item in consideration. Simple fact, borne out by the laws of physics. Even in a vacuum, the item would radiate energy until the two are in equilibrium. With conduction and convection in operation, that process will be much faster.

How it might be distributed will depend on other factors.

 

[user 6228]

Cite the paper if you likes

No need to bother. The bees will still heat the cluster and anything else will simply follow.

Heat transfer to the surroundiings is inevitable if they are at a lower temperature than the item in consideration. Simple fact, borne out by the laws of physics. Even in a vacuum, the item would radiate energy until the two are in equilibrium. With conduction and convection in operation, that process will be much faster.

How it might be distributed will depend on other factors.

they are not" in a cluster"

 

[oliver90owner]

And between 16 and 20 (according to you in the chatroom?). That doesn't seem to me to be a constant 18 degrees. C'mon, make your mind up and don't quote different figures, at the same time in different places!

Your words were ''...nail to 2C of 18C''

 

[Spadaman]

In "Beekeeping at Buckfast Abbey" , Brother Adam relates how he undertook a series of trials on hive insulation - he talks about 4" on the bottom , 6" on the sides and 8" on the top. No issues with condensation - all hives dry and no mould. However , without exception all colonies failed to build up in the spring. The colonies without such protection made rapid strides in the spring build up.

He tested this again the following year and had the same results. A few years later his friend A W Gale also undertook a trial with 40 hives at the same time Br Adam did a further trial with another 128 hives on two locations. They both had the same results. In other words insulation was not only unnecessary but positively detrimental on the well being of the colonies.

Sometimes common sense ( insulting roof with cut out for feeding fondant ) does not always work.

I wish I had read this before I bought some kingspan insulation for my hives!

Incidentally, this short book has some very interesting and enlightening tales of his experiences ( over 70 years) of beekeeping.

 

[drstitson]

brother adam didn't have OMFs!!!!!

 

[user 6228]

And between 16 and 20 (according to you in the chatroom?). That doesn't seem to me to be a constant 18 degrees. C'mon, make your mind up and don't quote different figures, at the same time in different places!

Your words were ''...nail to 2C of 18C''

GOTCHA!!!!!!!!!!

RAB you bit the bait on that one... you just listen in on the chat room with an "AWAY" on the end of you name dont say hello and dont say anything all evening you just eavesdrop and see if you can pick up tidbits to use against people by reading the log afterwards...

I put that line in especially for you to see if you were upto tricks I wasnt disappointed

it related to the day I put the Ecke on it dropped to 16c for one reading
then came back up. Which is even more amazing as it shows they are controlling the space even with volume changes