Home-made hive insulation

[tjc1]

For what it's worth, I have used this method the last two years (this will make 3) with good results Inexpensive and all the materials are reusable.

Pictures are pretty self-explanatory. There is a 2" shim on top of the upper box for mountain camp sugar. The FIberglass is wrapped and taped enough to hold it on while you cover with the plastic, which is stapled to shim above and tucked under below. Above the inner cover is an empty super with a bat of fiberglass in it, paper side down, inner hole covered with flashing taped on.

There is a skirt of tar paper on the super so that water doesn't run down behind the insulation. This is stapled to the super only. This way, the super lifts off and the inner cover can be removed for late winter inspection/addition of dry sugar. The vent in the inner cover is open in the front.

[rookie2531]

Looks cozy  :)

[BlueBee]

I agree; they look cozy. :)  It looks like your design would also collect some solar heat on a sunny day as well due to the use of the tar paper on the super.  The only problem is our building inspector would say you've got the vapor barrier on the wrong side. :-D  OK, that was just a joke.  Good luck this winter.

[tjc1]

Actually, I thought about the barrier being wrong way round, but I needed to be able to tape the bat to itself while installing. Then there's the tarpaper on the other side - a barrier sandwich? When I've removed everything in the spring, there have been patches of moisture here and there under the paper, but never dripping wet.

[JackM]

Yes, you have multiple barriers, not such a good thing.  The backing on the insulation is one, the plastic another, the tarpaper the third.  What you see is one thing, what is going on in the hive?  Have you vented it well enough for moisture to get out?

[BlueBee]

The number one problem with fiberglass insulation is its lack of resistance to airflow.  You gotta keep the air/wind from infiltrating it somehow or it becomes worthless as an insulator.   In a building they would put all low perm vapor barriers against the warm side (bees) and wrap the exterior (cool side) with a high perm house "wrap" like tyvek.  The tyvek breaks the wind yet allows vapor to flow (out) through it; hence preventing moisture from collecting and condensing inside the insulation and short circuiting it.  However on a house you would have some exterior cladding/siding over the house wrap to keep water out and the house wrap alone won't withstand the pounding from the Sun's UV.  So unless you want to add siding to your hives, your compromise is probably the most reasonable. X:X  You definitely need to keep water vapor from getting into the fiberglass (from the bees) and so in this case, I would go with the vapor sandwich too.    

[tjc1]

Yes, you have multiple barriers, not such a good thing.  The backing on the insulation is one, the plastic another, the tarpaper the third.  What you see is one thing, what is going on in the hive?  Have you vented it well enough for moisture to get out?

The upper entrance in the inner cover is open, allowing some airflow and venting of moisture. The insulation over the inner cover keeps the top inner surface warm so moisture doesn't condense there (when I've opened to inspect or add sugar, this has always been the case). In the spring, the places where it is clear that it has been humid are the back corners and sides of the hive. There is occasionally a little condensation at the top of the plastic wrap, but at removal, the fiberglass has been dry.

[labradorfarms]

Looks to me like the tar paper alone would be ok..

[JackM]

Ok whatever you wish.  At one point in my life I was an insulation contractor.  I agree fiberglass is a poor insulator as it does allow the flow of air.  Wrapping the whole batt in plastic would do a better job.

On my hives, I use 1" thermax (R4 ) plus a 1/2 inch air gap between the hive and the insulation on all sides (that effectively doubles the insulation to R8).  

This will surely get folks adrenalin going....I also leave my screened bottom open all winter.  I live in very humid cool environment.  This stops the mold growth inside the hive.  I also noted last year (my test year) that the hives that had open bottoms started the season like gangbusters....two to three times better start.  I also use Vivaldi board under the top cover, which really vents well.  Also on the bottom is a Miller board to disrupt air currents and prevent fast air flow through the hive.  And they are protected from the wind.

Yesterday as soon as the sun got on the hives they were active.....at 29 degrees.  That says a lot in itself.

Personally I think our biggest issue with winter and hives is getting the cold moisture out.

[tjc1]

Thanks for that info, Jack - I can see the benefit to wrapping the whole bat in plastic first - will try it next year!

[Eric Bosworth]

Why not just use Styrofoam? It is stiff so it can easily be installed on the outside of the hive and it does a good job as a wind break. 

[tjc1]

Mainly because I had a roll of tarpaper and a roll of insulation taking up space in my shed:)

[hjon71]

Mainly because I had a roll of tarpaper and a roll of insulation taking up space in my shed:)

Makes perfect sense to me.

[Eric Bosworth]

That is as good a reason as anything I could come up with.