Making Insulated Inner Hive Covers

PREFACE (OCTOBER 08, 2015): I made these insulated inner covers once and didn’t make them again because a piece of insulation over the inner cover in the winter position works just as well and requires no work other than cutting the insulation. I also use moisture quilts instead of hard insulation. See the updates at the bottom of this post for all the details.

The two insulated inner covers with venilation holes / top entrances cut in front.  (Oct. 15, 2010.)

The two insulated inner covers with venilation holes / top entrances cut in front. (Oct. 15, 2010.)

Winters in St. John’s, Newfoundland, provide a messy mixture of rain, snow and high winds with irregular periods of freezing and thawing. Wrapping Langstroth honey bee hives with a Type 15 asphalt felt isn’t a bad idea. Neither is installing mouse-proof entrance reducers. Preventing condensation, though, is the top priority. A 1-inch thick piece of R5-rated hard insulation over the inner cover in the winter position will prevent condensation from building up inside the hive during the winter. We used a 1.5-inch thick piece of insulation during our first winter (because we couldn’t find anything else) up until the end of January. Then we had to switch to insulated inner hive covers because the regular inner covers don’t provide enough room for candy cakes and pollen patties. A shim lifting a regular inner cover up an inch or two would provide enough space. However, an all-in-one insulated inner hive cover might be more convenient. It requires moderate carpentry skills (which means we’ll probably go with the shims instead), and it’ll cost a little more, but here’s how we made them if anyone is interested. We’ve tested them, and they work.*

You will need a piece of lumber close to an inch thick and 2.5 to 3 inches inches high (to be cut into 20 and 15 inch long pieces). You will need some 1-inch thick R5-rated hard insulation (cut to fit inside the cover’s outer frame). You will need a thin sheet of wood or high-density fiberboard (also cut to fit inside the frame). You will need some short thin nails. You also will need some screws and maybe some carpenter’s glue.

Frame for 1 of 2 insulated inner covers. It's essentially a rim, a spacer, an eke. (Oct. 15, 2010.)

Frame for 1 of 2 insulated inner covers. It’s essentially a standard rim, a spacer, an eke. (Oct. 15, 2010.)

The following instructions aren’t precise, but they don’t need to be. What you’re aiming for is a frame the same width and length as a regular super that will hold a piece of hard insulation about two inches above the top bars in the top brood box. The insulation prevents condensation build-up. The space beneath the insulation provides room for candy cakes, pollen patties — and the bees. Our bees clustered heavily at the top of the hives during the first winter, probably from running low on honey (see this video). At least 2 inches, maybe even 3 inches, of space would reduce the likelihood of the bees getting squished after the pollen patties and candy cakes are added. Without the extra space, the bees cling to the inner cover and get squished by the pollen and candy cakes when the cover is put back in place. That’s why the height of the frame can be anywhere from 2.5 to 3 inches. It depends on how much room you want to give the bees.

1) Cut the lumber into 15 and 20 inch pieces and screw them together to make a frame that will fit over your top brood box (see the above photo). The side pieces are 20 inches long. The end pieces are 15 inches long. The exact dimensions may vary depending on what kind of supers you have. We somehow managed to screw them together at more or less right angles so the frame fit right in line with the top of a super. But it was pretty rough. A T-square comes in handy.

2) Cut a piece of hard insulation so it fits snugly inside the frame.

Cutting the insulation for the inner covers. (Oct. 15, 2010.)

Cutting the insulation for the inner covers. (Oct. 15, 2010.)

The dimensions will vary. Ours turned out to be 38cm x 47cm, whatever that is in inches.

The top of the cover. The insulation is level with the wood frame. (Oct. 15, 2010.)

The top of the cover. The insulation is level with the wood frame. (Oct. 15, 2010.)

If the lumber is 3 inches high and the insulation is an inch thick, that should leave about 2 inches of space beneath the insulation (or in this photo, above the insulation). Our lumber was 2.5 inches high and the insulation was 1.5 inches thick. It left us with only an inch of space, which we discovered was barely enough room for candy cakes and high clustering bees. (We make the mistakes so you don’t have to.)

3) Cut your thin sheet or wood or high-density fiberboard to fit inside the frame, and place it right on top of the insulation. Brace the board in place with thin nails like this:

Then held the thin wood in place with nails. (Oct. 15, 2010.)

Then held the thin wood in place with nails. (Oct. 15, 2010.)

We drove the nails in at an angle, and then banged them down flat to hold the board in place. The board should fit a little loosely into the frame so you can see bits of the insulation through the cracks on the outer edges.

4) Cut a normal sized ventilation hole / top entrance at the front of each inner cover. Once the bees have been fed for the winter, the insulated inner cover is placed over the brood chamber to replace the regular inner cover. The outer cover is placed as usual on top of the insulated inner cover. And that’s it. The top entrance may not be sheltered by the outer cover, but our bees didn’t seem to mind.


For the less carpentry-inclined beekeepers, a simple piece of insulation over a regular inner cover like this will also work (show here without the top cover on):

Hive with 1.5 inch R-7.5 insulation over inner cover. No outer cover. (Nov. 2, 2010.)

Hive with 1.5 inch R-7.5 insulation over inner cover. No outer cover. (Nov. 2, 2010.)

But when it comes time to add any pollen patties or sugar cakes, you’ll need to use a shim to provide an extra inch or two of space.

* We tested the insulated inner covers and the simple piece of insulation over regular inner covers, and they both did a great job at preventing condensation over the winter. But note that we used 1.5-inch thick R-7.5 insulation, not 1-inch thick R5-rated insulation. I was told by a local beekeeper with over 20 years of experience that R5-rated insulation works just as well. We’re taking his word for it. But if you want to play it extra safe, use the higher rated insulation instead. We will update this post if we discover any problems with these designs.

UPDATE (August 09/11): These ventilator rims might work just as well as the insulated hive covers. I haven’t tested them in the winter yet, and I’m not sure if I’m willing to chance it. But if they did work just as well in the winter, I’d just keep them on all year and never bother with the insulated inner covers. I’ll get back to you.

UPDATE (August 11/11): The simple piece of insulation over the inner cover works perfectly. The only issue with that method and the insulated hive covers is that there’s not enough space for candy cakes or pollen patties that are added around late January or February. Therefore, I would use a two-inch rim (or eke) for the simple piece of insulation set up, which would also work for the insulated inner cover set up. But if I make any more of the insulated inner hive covers, I’ll simply use a taller piece lumber, one that’s at least 4 inches high. I’ll probably just use a 2-inch high rim, though, because it seems like the simplest solution. Then don’t forget to wrap your hives.

UPDATE (Oct. 18/11): Some beekeepers place the piece of insulation under the inner cover, not over the inner cover like we’ve demonstrated here. If you go that way, just make sure you still have an upper entrance for ventilation. Ventilation is key.

P.S.: Make sure to remove the insulated inner covers from the hives before spring. See Big Time Burr Comb for more info.

BIG UPDATE (Feb. 02/14): Moisture quilts can be made with a saw, a drill, a few other do-dads and minimal carpentry skills — and, for me, they’ve proven to be worth the effort (and they’re not too costly). I more or less made the moisture quilts by stapling window screen to the bottom my ventilator rims.

I made the switch from simple hard insulation over the inner cover to moisture quilts about a month ago because I noticed the insides of my hives were soaked (possibly because they were moved to an exceptionally foggy location this past year). A month later my hives are dry inside, dryer than I’ve ever seen them.

It’s still too early to make the call, but so far I’m very impressed, almost astonished at how well these things wick away all the moisture from inside the hives. Even after a month of rain, high winds and crazy temperature fluctuations, my hives are dry as a bone.

I held out on the moisture quilts until now because I was tired of always having to build something new for my hives (beekeeping isn’t the most affordable hobby for working class folk), but the moisture quilts, probably more than anything else I’ve built, seem to be worth the extra effort.

NOVEMBER 10, 2015: See Moisture Quilts vs Hard Insulation for an explanation and demonstration of both methods. And here’s a video that demonstrates how easy it is add a piece of hard insulation over the inner cover, essentially creating an insulated inner hive cover (taken from my Quick & Dirty Hive Preparations post):

9 thoughts on “Making Insulated Inner Hive Covers

  1. I checked under the hood and noticed lots of condensation building up under the outer covers this morning (some earwigs too). So I cut two pieces of hard insulation to fit over the top hive feeders in both hives and placed them under the top covers. Neither hive is taking up much syrup. It’s below 10° C most days, so they’re just not making the move up to the feeders too fast. Plenty of drowned bees, but I’m not worried. Only another week until November. At this rate, I doubt either hive will be taking up much more syrup.

    I’m going to install the mouse-proof winter entrance reducers the next warm day we have. I’ll check to see if any mice are already in the hive first. (I’ve also pulled out large slugs from the bottom of the hives. Newfoundland is wonderful like that.)

    Then sometime in the first week of November, I’ll remove the top hive feeders, install the insulated inner hives covers (or I might just put a piece of insulation over the regular inner covers and be done with it) and wrap the hives in felt (or tar paper). And then I won’t touch them again until probably February 2011.

    That’s the tentative plan anyway.

  2. We just finished building 16 of your lid design. We left a 1.5 inch gap for the bees above the frames. When do you place these lids on? Are they able to winter the bees all through the winter or just early Feb onward? Currently my hives have an inner cover with screen empty box with burlap and the 1.5 inch polystyrene sheet on top of the burlap before the lid. Works great here. But I’m looking forward to the potential to feed early and safeguard against starvation.

  3. When do you place these lids on?

    This is only our second winter of beekeeping, but around here we put them sometime in November.

    Are they able to winter the bees all through the winter or just early Feb onward?

    We kept them on the hives from November to early April last year.

    I’m looking forward to the potential to feed early and safeguard against starvation.

    We added four pounds of dry sugar to each of our hives on Dec. 31 as a precaution. We’ll check them again sometime in February, though I’m not convinced they’re running low on honey. The hives seemed full of honey back in the fall.

  4. Phil,

    I pulled the outer cover, Insulated cover(eke) then inner cover off several of my colonies last weekend when it was 5°C to take a quick peak. While the bees are are the top they have hardly made a dent into the candy cakes. It was good to see. If anything I have a concern they will have to much stores come spring and I need to get it out of the cells before things crystallize.

    I assume if the honey crystallized in the comb when the weather gets warm enough the bees will collect water to redissolve it? I hope.

  5. I’ve seen my bees hanging off the bottom bars in the bottom box from time to time. So even though they’re also clustering over the top bars in the top box and eating some sugar, I don’t think they’re necessarily up there because they’re low on honey. They may be up there simply because it’s warmer up there. I wish I could see how much honey they have in the bottom box.

    I’ve read Canola honey will often crystallize in the comb. I suppose golden rod honey might do the same. I have no idea what bees do with crystallized honey in the comb, but millions of years of evolution have likely provided them with some kind of solution to it. Like you said, probably water to redissolve it.

    [A few minutes later…]

    Yup, it’s not a problem:

    “…the bees will expand, consume, and clean up the crystallized honey, nicely. If they truly have to expand in a hurry, they will carry the honey crystals and dump them outside the entrance of the hive on the ground.”

    At least that’s one beekeeper’s opinion.

  6. Perfect, I have a couple of foundation frames left in the colonies that need to be drawn out. That gives the bees the chance to make some space and use up the resources. Also I plan to remove a couple of empty frames this spring to have some excess drawn foundation just in case.

    I’m hoping to have 12 – 14 drawn empty comb just in case.

  7. That’s cool.

    Sorry I haven’t touched base lately. I’ve been run ragged with work. It’s feast and famine in this freelancing business. It tires me out sometimes.

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