Some beekeepers find cover cloths are useful to lay across a box of combs to prevent the bees from running over the tops of the frames when the hive is open. They can be made from pieces of light deck-chair canvas or similar material, with a batten fixed at each end. The width of the material should be slightly greater than the length of the top-bars of the frames and the length just sufficient to allow a batten to hang over each side of the box.
The battens should be heavy enough to keep the cloth flat when laid over the hive and to prevent it being blown off by the wind. The battens, used as rollers, enable a pair of cover cloths to be used so as to expose one frame at a time when examining a set of combs in a brood box or super.
The top-bar hive is so named because the frames of the hive have only a top bar, not sides or a bottom bar.
The beekeeper does not provide a foundation (or provides only a fractional foundation) for the bees to build from.
The bees build the comb so it hangs down from the top bar
This syle of hive is also known as the Kenyan Hive
The hive body is often shaped as an inverted trapezoid in order to reduce the tendency of bees to attach the comb to the hive-body walls.
Unlike the Langstroth design, a top-bar hive is generally expanded horizontally, not vertically.
The top-bar design is a single, much longer box, with all the frames hanging in parallel. Unlike the Langstroth hive, the honey cannot be extracted by centrifuging because a top-bar frame does not have reinforced foundation or a full frame.
Because the bees have to rebuild the comb after each harvest, a top-bar hive yields more beeswax but less honey.
However, like the Langstroth hive, the bees can be induced to store the honey separately from the areas where they are raising the brood.
Therefore, bees are less likely to be killed when harvesting from a top-bar hive than when harvesting from a skep or other traditional hive design.