Beemaster's International Beekeeping Forum

For those of you who shim your tops for the purpose of added ventilation for your hives in hot weather, (add a shim in between the top and top super), do you add a screen on top of your top super to help prevent SHB from entering the open space now made available by this method of ventilation of heat relief?

We have an inner cover that has a center hole that we have covered with hardware cloth. We open just the back of the outer cover for ventilation. We see SHBs, but they don't seem to be any worse since we started doing that last year.

Not the answer to the question you asked, but sometimes I put 1-1/2? thick foam with the foil side up on top of the telescoping cover to reflect the heat. It?s cut a little oversized to provide a little shade too.

If I recall; it has been posted that the best method for heat is not more ventilation, but instead to insulate.  Insulation protects from heat just as well as it protects from cold.

Quote from: TheHoneyPump on June 22, 2021, 10:50:26 PM
If I recall; it has been posted that the best method for heat is not more ventilation, but instead to insulate.  Insulation protects from heat just as well as it protects from cold.

True, insulation tops have been discussed here before. I have also used these as well (2 inch insulation to be precise). I have discussed that very thing here with my results as well, and recently. I had a drawback. Perhaps not enough to be concerned with but I thought I might try something a lifetime beekeeper from my area has recommended. I did not know if others here might have attempted the vented top as well, so I decided to start this topic.

As a (newer) beekeeper, fourth summer,  I like to experiment with different ideas and suggestions which seem reasonable and then weigh the results, then deciding which works best for me in my area. Vented tops have been recommended to me as a valid avenue for releasing heat in a over-bearded overheated hive here in the South. Not being one to be stuck in one mode but attempting to be open minded when reasonable, I thought I would try the vented option as described this season. I recently did so. I am happy to report it has proven to work "very well" in my location.

Always a threat in summer, Small Hive Beetles in my location are not to be taken lightly as noted. That is why I ask the question; Should screen tops be added when wedging, (venting), the hive top. Should the two be used together, is why I started this topic. Your input is very valued Mr Honeypump. Vented tops in my area work. Do these have to be screened because of SHB is the question. Hopefully I will find more answers concerning the two. I can always go back to insulated if I find insulated works best for me. I bet  you are thankful that you do not have to deal with these awful pest; SHB ...  Rough customers at times.

It is a great question on the screens for stopping SHB.
For sure am thankful to not have SHB threat here. Nor the heat temperatures.  My -normal- sunny day is 75F.  Though we have a heat wave on the way for this weekend, 95F .  ( I will be in the cool basement watching movies ). 

I can?t verify anything about the screens for the top, but is seem like it?s worth a shot. I don?t see what it would hurt. Even, if not for the beetles, the hornets and wasps.  I?ve noticed moths like to hang out under the shaded lip of the telescoping covers.

It may not be the hiccup you had, but I recall reading about someone?s bees chewing through the insulated tops. I place my foam over the telescoping cover. Is it tacky looking? Depends on how picky one is. If one likes the results, they may not care so much about the appearance. From 40? away does it look that much different than a white cover with aluminum flashing on top?

But don?t change what isn?t broke. If the vented covers are working, I don?t see a downside to the screens being added.

Quote from: .30WCF on June 23, 2021, 11:59:41 AM
I can?t verify anything about the screens for the top, but is seem like it?s worth a shot. I don?t see what it would hurt. Even, if not for the beetles, the hornets and wasps.  I?ve noticed moths like to hang out under the shaded lip of the telescoping covers.

It may not be the hiccup you had, but I recall reading about someone?s bees chewing through the insulated tops. I place my foam over the telescoping cover. Is it tacky looking? Depends on how picky one is. If one likes the results, they may not care so much about the appearance. From 40? away does it look that much different than a white cover with aluminum flashing on top?

But don?t change what isn?t broke. If the vented covers are working, I don?t see a downside to the screens being added.

I am not disputing that insulation board helps, I have used them.  This season, I have moved on to a wedge ventilation on top and am asking about the possibility of needing screen for reasons explained to HoneyPump earlier in my detailed reply number 4. As I told Mr HoneyPump, If I find I am not happy with this experiment, I may very well go back to insulation board. I am not attempting to convince others to try something I am in the middle of learning myself. lol

Can it hurt a hive with this small amount of added ventilation allowed throughout the hive here in the hot South if done properly? This type Ventilation vs bees steady working hard to achieve ventilation in an enclosed hive where no air can move except by hard work of the bees fanning to stir the air? Is there a downside?

The downside of screens (if needed) is the time involved to produce them. Scrap board ends to produce frames for these screen tops are free from construction sites. A roll of screen is not very expensive if broken down (per-hive).

30 another upside of screens added are the Critters you mentioned can not come in through the top, but they can enter the bottom opening as always. So the same question, are screens needed at the top wedges? 🤷🏻‍♂️

I have inner covers with hole cut out for jar feeder with screen across it.  They all get propolised shut by the end of the season.  If the bees can't get through they will eventually close it off.  I have a few boxes on a couple hives that don't fit very well.  Instead of closing the gap, they chewed it until it got big enough for them to get through.  Now they have a second opening  which they tend to use more often. 

With that being said, back to you original question.  I don't think that a screen would make any difference.  I also don't think that bearding is a bad thing.  It just means that it is warm enough inside that they don't need the extra heat from all those bees.  As long as your comb is not falling apart from the heat your bees should be fine.

Quote from: cao on June 23, 2021, 06:01:34 PM
I have inner covers with hole cut out for jar feeder with screen across it.  They all get propolised shut by the end of the season.  If the bees can't get through they will eventually close it off.  I have a few boxes on a couple hives that don't fit very well.  Instead of closing the gap, they chewed it until it got big enough for them to get through.  Now they have a second opening  which they tend to use more often. 

With that being said, back to you original question.  I don't think that a screen would make any difference.  I also don't think that bearding is a bad thing.  It just means that it is warm enough inside that they don't need the extra heat from all those bees.  As long as your comb is not falling apart from the heat your bees should be fine.

Thanks Cao...  I am not going to give the screens much more thought. I will keep a
close eye on things.

 In my beekeeping youth, I tried all the anti-bearding tricks and all either created a problem or extra work for me and or the bees or didn't show enough of an improvement to warrant the extra expense, think slat racks. Imrie shim just used more guard bees and no additional honey. Screen bottom boards let the powdered sugar fall through all right, but didn't take enough mites with it and hives still died. They also let ants and other critters up into the hive. Wax frass still built up on the edges so moths laid in it. Just like cao, they prop it up or open it up and just usually guard it if opened. My hives are like that hollow tree today and yes they beard.   

Once the ambient temperature is above 93F even if they are in the shade, and if it is close to that and they are in the sun, the bees are no longer ventilating, they are cooling.  They haul more water and evaporate more water.  Opening things up more is like leaving the door open with the air conditioner running...

Quote from: Michael Bush on June 24, 2021, 05:39:52 PM
Once the ambient temperature is above 93F even if they are in the shade, and if it is close to that and they are in the sun, the bees are no longer ventilating, they are cooling.  They haul more water and evaporate more water.  Opening things up more is like leaving the door open with the air conditioner running...

That makes sense... great answer, Thanks Mr Bush..

You seem off of the screens, Phillip, but for anyone who is curious, #8 screen doesn't stop SHB, although it does slow them down.  I saw one squeeze through a screened inner cover today.  It was tight, but the little bugger made it through before I could smash him.  :angry:  I did get his friend though.  :happy:

I have just read a research project on hive temperature and what effects the bees.
I will try and find it and post it if i can.
The guts of it was that insulation is the most important, ventilating the top of the hive upsets the bee cooling system, creates air flow that interferes with their air movement for cooling. Even lid vents, 2 x 3/4 inch holes each end in the lid are only effective when transporting hives.
We have about 30 hives that have wooden insulated lids with no vents and they perform well. I will now take more notice whether they are performing better but they are spread around a few loads.
The polystyrene hives are the most effective for bees to survive extremes of temperature, the Paradise hives we use have no lid ventilation and have done well in 100F full sun. (Not done on purpose, got my compass directions messed up and unloaded before sun got up, the shade missed the hives)
The ventilation is again human logic not matching up with bee logic.

Quote
I will try and find it and post it if i can.
The guts of it was that insulation is the most important, ventilating the top of the hive upsets the bee cooling system, creates air flow that interferes with their air movement for cooling.

Oldbeavo,
In that case I am glad I kept my insulated hive tops! Back to them I go without hesitation.. I am glad I ask and I appreciate all responses!

Quote from: Ben Framed on June 23, 2021, 12:57:58 PM
30 another upside of screens added are the Critters you mentioned can not come in through the top, but they can enter the bottom opening as always. So the same question, are screens needed at the top wedges? 🤷🏻‍♂️

Is that kind of like saying that I could get a 50% reduction in my light bill by turning off the lights when I?m not using them. But, I do use my lights sometimes, so why not leave them all on all the time.

Quote from: .30WCF on June 24, 2021, 09:09:23 PM

Quote from: Ben Framed on June 23, 2021, 12:57:58 PM
30 another upside of screens added are the Critters you mentioned can not come in through the top, but they can enter the bottom opening as always. So the same question, are screens needed at the top wedges? 🤷🏻‍♂️

Is that kind of like saying that I could get a 50% reduction in my light bill by turning off the lights when I?m not using them. But, I do use my lights sometimes, so why not leave them all on all the time.

The main reason I was interested in these top screens was to help keep SHB from the luxury of entering at both ends.  I suppose these screens might have been an aid for the added pest you mentioned, if so, so much the better.

As mentioned in my last post I have decided to go back to my insulate tops. The supporting testimony?s of several of you here including Mr Bush and the clincher, the evidence of OldBeavo made perfect sense. Thanks again for each of your comments.

Every time I've put any kind of screened ventilation cover, the bees have covered it entirely with propolis. I finally got the message.

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I am many others use screened bottom boards, so the bees will herd the beetles through the 1/8" mesh down on top of the West Beetle Trap below.  So 1/8" keeps out bees, but not SHB.

Re: top entrances
Cupolas...Ridge Vents...commercial cooking fans...
If my garage didn't have a venting fan it would be brutally hot. 
https://www.bobvila.com/articles/attic-ventilation/

I leave a small top entrance in an imirie shim, on big hive.  I have insulated lids with reflective tin. 
20 bees can either hang on the lid inside ... and fan out the rising hot air .... or cluster around and block the gap... as they choose...

https://www.bobvila.com/articles/attic-ventilation/

QuoteRe: top entrances
Cupolas...Ridge Vents...commercial cooking fans...
If my garage didn't have a venting fan it would be brutally hot.
https://www.bobvila.com/articles/attic-ventilation/

FloridaGardener you have made a great point! HEAT rises. Cooler air falls. With the bees (air conditioning running), it would seem the cool air generated by their water cooling system would be more effective if the hotter upper air of the hive were allowed to escape? Tim Durham believes in venting. He is the lifetimer beekeeper that I learned it from by watching his videos.  Therefore the heat is not trapped, while the bees are generating cooler air via their water cooling system, The hotter air escapes. You have me thinking again; just when I had decided to go back to insulated tops once again lol. I can definitely see a major difference in bearding since I wedged the tops. So which way is the best? I do not know. Thanks for your post. It is definitely food for thought!

Adding more complicated food for thought, In the house itself, we do have insulation in the ceiling between the attic and roof. Making it easier for our AC units to cool our dwelling place of the house. So there is another monkey wrench thrown in the gears to consider?..  lol
Adding: Your analysis of ridge vents really stand out irregardless of area, dwelling attic area or garage area, both areas are cooler than they would be even on the hottest days!!..

Thanks again..

Beekeepers should stop thinking about bees cooling hives the way we cool our houses.  Bees don't intend to cool the air as we do with AC units, they intend to cool the comb.  They do this by evaporating water on the comb surface and at the entrance to cells, so we should remember pre AC days and a fan moving air over our skin.  Fanning helped some if we were in the sun, it worked better if we moved into the shade, and it worked best if we wiped our exposed skin with a damp cloth.

We can help our hives cool by reducing the effects of solar heat by painting them white, placing them in the shade, or using shade boards, or using insulation on tops/sides of the hive, using open mesh bottom boards and hive stands to elevate them, and having a water supply close by. 

Bees fanning comb that is outside the hive in the shade, can cool the surface of that comb using wing power, so why should we worry about the number of entrances to a hive?  Bees fanning at the entrance of a hive are moving the air through the hive and out of the entrance at a rate of 220 to 250 cubic feet per minute which is more than enough to remove the body heat of the bees that remain inside the hive along with the more humid air from evaporation of the water.  Do we really need to add openings at the hive top so that the heat can escape?

Maybe not, but it makes me feel better because I give them the option - provided it's a small opening. 

And when the hive boxes are 5 high and there's a QX at between box 3 and 4, I do notice a few - but certainly not all - bees enter at the top opening. Maybe it's a shortcut to offload nectar when the bottom boxes are traffic jammed.

>I will try and find it and post it if i can.

I would like to see that study...

>why should we worry about the number of entrances to a hive?

According to Huber (Huber's New Observations, Bicentennial edition, page 461:

"5th Experiment:  Increase in openings decreased  ventilation.
We tried increasing the number of openings in the side of the box, but were not successful.  One of the two candles went out at the end of 8 minutes.  The other kept alight as long as the ventilator was in motion.  I had therefore not obtained a stronger current by multiplying the openings.
These experiments show that in a place with an opening only on one side, air can renew itself when there is some mechanical cause tending to displace it, and this seems to confirm our conjectures on the effect which the fanning of bees has on the hive."

'Tis true that with no a/c in my car, I can roll down the window on only the driver's side, and feel cooler.  One opening does allow sufficient ventilation.

Another thing that really helps keep it cool is to leave enough capped honey (in the out-cycling brood comb) to be 6-3/4" of insulation on top.  Rather like tinted windows. 
Of course...for me... that means I must unload half the super into a workbox, before I can lift it off the top of the stack...
:cheesy:

Again part of the beauty of beemaster is folks getting together as we are doing here, discussing a subject with each participating member bringing in fresh ideas and prospectives of points of view to the round-table. Together we strive to find what is reasonably best for our bees.

I don?t just create an opening on top. Actually my tops are flat solid pieces of Advantec. No lips, no divots. Just a solid board for a top. I have never had a top come off or blow off. 3/4 inch Advantech is pretty heavy. The quarter inch wedge gives ventilation along the entire width of the back, but also the two sides. From zero gap at the front and gap increasing wider as we finally reach the full quarter inch gap at the back. This gives a goodly amount of ventilation to theoretically give a slight vent of moving of inside atmosphere. Again I am not advocating others to do this, though I am still in the process myself of this experiment. (I have not placed the insulation boards back in my tops yet... 😊

All your thought are welcome and appreciated.

The research project that i read stated that the opening of the lid provided what they called vertical  chimney like draft. It is effective in cooling the hive.
But they spoke about the convection air currents created  by  the bees are thought to be horizontal across the brood frames.
The bees bring in water to cool are using the convection currents to cool.
On insulation, the 7/8 - 22mm wood of the hives has an R factor of 1.2, while 1 1/2" - 40mm of poystyrene is an R factor of 7.9.
There is also thought that the outside frame that is usually full of honey works as a heat sink to capture incoming heat or hold heat in cold weather to protect the brood.
,
.

Perhaps the bearding bees had to return to guard duty with almost 3/4 of the top of the hive open.

Quote from: The15thMember on June 24, 2021, 07:21:59 PM
You seem off of the screens, Phillip, but for anyone who is curious, #8 screen doesn't stop SHB, although it does slow them down.  I saw one squeeze through a screened inner cover today.  It was tight, but the little bugger made it through before I could smash him.  :angry:  I did get his friend though.  :happy:

Thanks Member, I used the #8  when I was making screen bottom boards for use with oil trays a couple years ago as recommended by Beemaster2 and Paus. This set up worked well as the bees were excluded from the oil trays by number 8 HWC. As you described, the number 8 allowed the SHB to go through to their doom. If I were to continue on, deciding to use top screens as discussed here, I would not use number 8 Hardware cloth, but regular metal window screen (aluminum). I have plenty of this screen left over from a home project here a few years ago. If I do not scrap this experiment and where to continue onward, the screen expense would only be an indirect expense.   

Philip why not just try it on one or two hives? It's not going to kill them.

My bet is they will have it 85% sealed by the end of the season, and 100% by next spring. But as long as you don't clean the screen, they'll have a good propolis envelope.

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Matt,
I use screen (window screen) tops in all of my hives. The bees normally only propolis the outer inch of the screen. They do sometimes add more each year. During winter months you can easily remove most of it just by moving the screen back and forth and most of if falls off if it is cold enough. I do have a few screens that I have not cleaned that only have a six inch hole in the middle. They were built up over many years.
Jim Altmiller

Thanks Matt and Jim, the screens would not be needed in my area during winter as SHB are not a problem at my location during the winter months. Therefore I would remove them. The Temperature usually drops into the 20s f every year, many years into the teens Fahrenheit some days, so cleaning what buildup should be a cake walk. Up until now I have not added any top screens.

My experience is the same as Jim's .  I also have started placing a cloth over the screen and putting shavings or sawdust about 1 1/2 inches deep , level full.  I leave it there all year as this is excellent insulation.  Sawdust is a better insulation but not as good for use in the smoker, in an emergency or just changing the sawdust.

In all this discussion about cooling , what is lacking is consensus on what ambient temperature level would be considered hot enough to warrant doing anything at all?  What is hot? What is the number?

The temp that seems hot for us is somewhere in the 95F+ range but with low humidity. We try to have our bees in shade by 11 o'clock. our Eucalypts provide a dappled shade but it is comfortable.
95 degrees in Arizona or 95 degrees in Florida, i would think that the higher humidity would test the bee cooling system.
Our rule of thumb is to have water as close as possible, no further than 300 yards is ideal.