Top Venting
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Thread: Top Venting

  1. #1
    Join Date
    Jul 2014
    Location
    Fremont, California
    Posts
    132

    Default Top Venting

    Bees need venting in the hive, all year long. The current hive design does not offer much, if any. The inner cover has a nice hole in the middle, but there isn't any air gap between the inner cover and the outer cover. No place for air to get out. Since hot air rises, the beehive is a natural chimney with all of the hot and humid air rising up to the top.

    In winter the high humidity condensates on the inner cover, causing droplets to rain down on the bees.
    In the summer, the solar load on the top cover is stifling hot, and the bees spend a lot of extra energy (= less honey and brood) to keep the box cool enough. Also, as they are trying to dehydrate nectar into honey (90% --> ~17% water content) it seems a very difficult trick of physics that they can do this with the inside of the hive being close to 90% humidity all the time. We need to add some venting to hive. Not a lot, just some.

    There are several concepts of top ventilation floating around. Serge Labesque is a big fan of ventilation, and his custom hardware has a 2 square inch screened port on his inner covers to let air out. He also recommends using follower boards on the sides to allow the cool air to flow around the brood chamber to let the bees manage their environment better. Many of our members put a pebble, or stick in between the inner cover and the outer cover. Many inner covers now come with a notch in them for ventilation, or a top entrance. I have converted some winter inner covers to year around inner covers with vents in them. (they are just tall inner covers) There is also a nifty device called a Vivaldi Board, which is very similar to winter inner covers with vents. https://www.youtube.com/watch?v=xKL46LKVqHs

    I have a new idea for venting that is cheap, durable, simple to add, and does't require you to keep track of sticks or pebbles. Its Coroplast. The corrugated plastic that is used for signs (mostly campaign signs) Its Tough, durable, cheap. Cut some 2" wide strips and staple them to the inside of your telescoping outer cover. Make sure the channels go from the inside to the outside. Leave a 1/2" around the outside for air flow. Staple or glue in place. (use a glue that remains compliant, like silicone. Wood glue and Gorilla glue are too rigid and will fail shortly as it doesn't bond well to polypropylene)

    IMG_1494.jpgIMG_1496.jpg

    You could also do this to your inner covers if you like. Just put the coroplast on the top side, as the bottom side will get propolized in week.

    Its not a lot of air flow, but it is certainly more than you had before. The bees will then be able to adjust the temperature
    and humidity much better now they have the added benefit of getting the hot and humid air out of the top of the hive. Happier bees. Less stress.

    Cheers,
    Phil in Fremont

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  3. #2
    Join Date
    Aug 2014
    Location
    England, UK
    Posts
    1,815

    Default Re: Top Venting

    Quote Originally Posted by hankstump View Post
    Bees need venting in the hive, all year long. The current hive design does not offer much, if any. The inner cover has a nice hole in the middle, but there isn't any air gap between the inner cover and the outer cover. No place for air to get out.
    [...]
    Its not a lot of air flow, but it is certainly more than you had before.
    Hi Phil - very few ideas are truly original (sorry about that ...). Here's the same idea from the 1960's - and was in use well before then - although people who employ Open Mesh Floors (SBB's) over here don't use top ventilation anymore.







    Taken from: British National Hive BS1300 (1960) - Ministry of Agriculture Publication.
    LJ
    A Heretics Guide to Beekeeping http://heretics-guide.atwebpages.com/

  4. #3
    Join Date
    May 2011
    Location
    Algoma District Northern Ontario, Canada
    Posts
    5,246

    Default Re: Top Venting

    Without any top ventilation a colony is very dependent upon the bottom entrance not becoming blocked by dead bees or packed snow. There are enough examples of successful wintering with no top venting to know that it is not absolutely essential providing bottom venting remains active. I have had an experience with highly insulated but no top venting setups possibly resulting in about 80% colony mortality due to bottom entrances becoming plugged with dead bees and hard drifted snow.

    Top ventilation is easy to overdo and especially where dips to -40 F.~C. are possible. The original posters idea or LJ are likely good for their respective winters. I want to see much more insulation factor in my climate

    The jury is still out whether it was a ventilation issue or not as I had reason to suspect brood disease might have prevented the crucial start of spring brood up.
    Frank

  5. #4
    Join Date
    Aug 2014
    Location
    England, UK
    Posts
    1,815

    Default Re: Top Venting

    Frank - I take my hat off to you guys for coping with those kind of conditions ...

    If I lived in one of the northern States or in Canada, then I'd either keep bees inside a bee-house, or pack 'em together in four's inside insulated crates.
    LJ
    A Heretics Guide to Beekeeping http://heretics-guide.atwebpages.com/

  6. #5
    Join Date
    May 2011
    Location
    Algoma District Northern Ontario, Canada
    Posts
    5,246

    Default Re: Top Venting

    Here is a link to some good advice about ventilation for cold climate beekeeping. I strongly agree with his reasoning.

    https://www.beeculture.com/winter-management/

    This winter was really mean in both temperature, duration, and no flying weather from Nov. through March. It did get above freezing a number of times but with rain and high winds. We got lots of drifting and about three feet of snow on the level. Layers of ice throughout the depth of snow. I am just starting to see a few dandelions but not really out yet. First drone larvae but not capped a week ago.
    Frank

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