A top-bar hive is a single-story frameless beehive in which the comb hangs from removable bars. The bars form a continuous roof over the comb, whereas the frames in most current hives allow space for bees to move up or down between boxes. Hives that have frames or that use honey chambers in summer but which use management principles similar to those of regular top-bar hives are sometimes also referred to as top-bar hives. Top-bar hives are rectangular in shape and are typically more than twice as wide as multi-story framed hives commonly found in English-speaking countries. Top-bar hives usually include one box only, and allow for beekeeping methods that interfere very little with the colony. While conventional advice often recommends inspecting each colony each week during the warmer months, heavy work when full supers have to be lifted, some beekeepers fully inspect top-bar hives only once a year, and only one comb needs to be lifted at a time.
There is no single opinion leader or national standard for horizontal hives, and many different designs are used. Some will accept the various standard frame sizes.
General information
Although the two most well-known styles of long top-bar hives are named "Kenyan" and "Tanzanian", the Kenyan hive was actually developed in Canada, and the so-called Tanzanian hive is not the same as the top-bar hive that was developed in Tanzania.
The design of top-bar hives has its origins in the work done in 1965 by Tredwell and Paterson. A tub shaped top-bar hive was trialled in Rhodesia in the 1960s by Penelope Papadopoulou. Long top-bar hives began to appear in the 1960s and were first referred to as "grecian" hives also known as the "Anástomo" wicker skep. Similar "long" top-bar hives were also developed in the early 1970s by other authors. The David Hive (1972) was similar to the Kenyan top-bar hive, except that the comb was not cut from the bars at harvest time but reused after extraction. Also in 1972, William Bielby designed a top-bar hive that featured catenary curved comb.
Design
Although guidebooks for use in Africa often give precise dimensions for the Kenyan hive, and encourage beekeepers to keep their equipment of uniform and thus interchangeable sizes, one of the main selling points of the KTBH among proponents from English speaking countries is the fact that it can be made to practically any size and shape, as long as the top bars have an appropriate width.
The angle of the sloped sides is most commonly recommended to be 30 degrees. The width of the top bars is the sum of comb thickness and one measure of beespace. This helps ensure that bees build exactly one comb per top bar. Most top-bar hive plans freely available on the internet show hives of roughly 1 meter long and between 30 cm and 50 cm wide and high.
In English speaking countries, the top-bar hive is usually mounted on a set of legs that lift the hive to a height that is comfortable for beekeepers. In African countries, the height of the hive is often also determined by the type of animal the hive is meant to be protected from.
Top Bars
A top-bar hive has bars from which the honey bees attach and hang wax comb, an array of hexagonal (six sided) cells.
A beekeeper can make top bars from any plain wood. The top bars are usually 1¼ inches to 1⅜ inches (32–35 mm) wide, depending on local conditions and the type of bee to be housed. Combs can be handled individually. The depth of the bar and the length of the bar can be whatever the beekeeper wants, but usually between 17" and 20". The depth of the top bar hive should be 12" or less. If deeper, the weight of the comb filled with honey tends to cause it to fall off the bar into the bottom of the hive. The bees will lose access to this during the winter cluster in the hanging combs, thus increasing their likelihood of starving.
It is important to give the bees a clear starting point to build comb on each top bar. Some TBH beekeepers fashion their top bars with a V-shaped bottom to guide the comb building. Alternatively, some use a table saw to cut two closely spaced slots along the long axis of each new top bar. Either type of guide, wax line or grooves, gives bees a place to hold on to with their hooked feet. This allows a substantial "drape" of bees to form, which is the beginning of comb building.
Entrance
Top hives have entrances that are a small slot or a number of holes of an inch in diameter or thereabouts, which more closely mimics what honey bees prefer in nest cavities.