Top-bar hives have multiple practicalities. They can make a wonderful educational experience for the modern beekeeper to learn to understand the instincts of their bees. The modern beekeeper, otherwise using Langstroth equipment, will learn how bees build a feral hive, while having the added feature of removable frames. Each frame is 1 and 3/8 inches across, with a 3/16 inch spaced between the front and rear walls of the hive and the first and last frames. This allows for a 3/8 inch bee space between all surfaces in the hive. The sides are oriented at a 120 degree angle to the bottom board, which follows the natural angle of the cells in the comb, thus reducing attachments to the sides of the hive.
Combs in a top-bar hive simply hang from the top-bar, and are not supported by a frame, thus they cannot be extracted. Honey is either harvested as comb honey, or it is crushed and the wax rendered for other purposes, such as candle-making. This is the second practicality of the top-bar hive. For a beekeeper who values wax along with honey, the top-bar hive is the best way to go. For each comb of honey he harvests, that beekeeper also harvests a complete comb of wax. It is true that the bees will then have to re-build that comb again during the next honey flow, but the bees do this very quickly, faster, in fact, than they can draw out foundation, from my experience.
Bees in a top-bar hive will not continually collect honey, as will bees in a Langstroth hive, even if there is space left at the rear of the hive. It is the beekeeper’s job to keep moving empty frames forward into the hive, about 2/3, from the front, into the front of the brood nest and just behind the first comb of honey. This assures that the broodnest never gets honey bound, and that there is always comb ready for the bees, as brood hatches from the rearmost comb of the brood nest. There is also a vacancy between two combs in the honey area, which the bees quickly fill. When moving new bars forward, it is best to insert them between two straight combs, as bees tend to naturally build curved combs, especially at the rear of the honey area. If you keep the bees building new combs between two good, strait combs, you will have the pleasure of not dealing with curved combs.
Honey from a top-bar hive will be harvested as comb honey. If the beekeeper wishes to have liquid honey, he must crush the comb and drain it of honey. One method of doing this is to press the comb between two wooden boards, using a car jack to build up the pressure. The wax is then cleaned in water and melted into a block for later use. Another method is to collect all harvested combs of honey in a clean bucket and then use a potato masher or some other implement to crush the comb, and then pour the honey through a filter to remove pieces of wax. The wax that is left behind can then be squeezed by hand over the filter, now containing a little honey and a lot of wax, thus squeezing the last bit of honey out of the wax. The wax is then cleaned in water and melted into a block for later use.
Leave the bees with a comparable surface area of comb to what you would overwinter your bees with in Langstroth equipment. This takes some calculations on your part, and the number of combs left will vary with the dimensions of your hive.
This is a very strong hive. They have drawn comb on 13 top bars (I think) but each top bar is bigger than a conventional deep frame. One of the biggest advantages of the top-bar hive is that the hives are much cheaper. I also find this hive much more fun to work than my two Langstroth hives. However, I will keep the lang hives because these will allow me to sell splits to other beekeepers. I am currently starting up a new beekeeper, who is buying two lang hives, and two splits (matured to the point of having a laying queen) from me for $80 each ($90 each for one, $80 each for more than one). One of the benefits with the top bar hive in this aspect is the bees raise more drones in top-bar hives, thus saturating my apiary with drones of desirable genetics to breed with my virgin queen.
The top bars are all added at once, as would be frames in a lang hive. The only measurements that matter are top-bars 1-3/8 inches wide, 3/16 inch spacers between the front and rear wall and the top-bars (I built these into the front and rear top-bars themselves) and a 120 degree angle between the bottom board and the sloping sides. This is the angle at which diagonal cells are to horizontal cells in honeycomb, and therefor this results in less comb attachments to the sides of the hive. I have had ZERO connections between combs, and minimal connections to the walls, which the bees do not rebuild once I remove the connections. This is my favorite hive. I would recommend building one for the pure enjoyment and learning experience it offers.
With the slanted sides, the bees tend to regard the walls and the bottom board as the floor of the hive, and build relatively few connections, which, once removed, they do not replace. It is necessary, however, to make sure your dimensions are correct so as not to leave any spaces larger or smaller than the bee space, thus eliminating the problem of burr comb. My only problem thus far has been slightly curved combs, curving toward the entrance at the ends of the bars. To solve this, I add an empty bar between two straight combs. The bees will draw this out, and then I will add another bar forward. As I get a good number of straight combs, I will move the curved ones toward the back of the hive for honey storage once the brood all hatches and the bees use up any pollen, and I will keep the straight combs for the brood nest. This way, I will eventually phase out any curved comb, and be left with only straight comb, which is easy enough to maintain once you have some to use as a guide for the bees.
The wonderful thing about a top-bar hive is that dimensions really don’t matter. I’ll tell you my dimensions. (these may not be exact, but are rough estimates unless noted). Accommodate wherever needed for the thickness of the wood you’re using (no less than 3/4 inch wood should be used).
Bottom of hive: 10 inches interior measurement
Height of hive: 12 inches interior measurement
Sides: whatever they work out to be. The angle between the bottom of the hive and the sides of the hive MUST be EXACTLY 120 degrees, in order to minimize comb attachments.
Front and back: trapezoids to fit
Bottom board length: a multiple (depends on # of top-bars, I like 30) of 1-3/8 inches plus 3/8 inch for the interior, plus the four inches extra for a landing board.
Measure the length to fit across the top of the hive, and add the thickness of the wood (which is cut at an angle, so it is thicker than the thickness of your lumber. 1-3/8 inches wide. Between your front top bar and the front of the hive, you will need a 3/16 inch spacer. Same for the back of the hive. Make some sort of a spline or ridge down the center of each bar, and rub the bottom edge of this with beeswax, or, even better, dip into melted beeswax. This gives the bees a starting point from which to draw out comb.
Now make yourself a weatherproof cover, with latches to hold it down during storms.
Now drill entrance holes for the bees to get in and out of the hive. Some of these holes will need to be flush with the landing board, so the bees will be able to clear the hive of dead bees and debris. I like the seven holes, 3/4 inch in diameter. I watch the bees, and if they seem to be struggling with not enough entrance room, I pull a cork from another hole, and if they seem to not be using all of their holes, I cork another one of the top ones. I will leave the bees with the bottom three holes for the winter.
I hope you’re handy, it will take you the better part of a day to build this hive, but it is definitely worth it in the end. I actually find the top-bar hive more fun to work with than my Langstroth hives.