Top bars are simple wooden strips that rest on top of the hive body. They:
- are spaced at 1 1/4″, the thickness of a brood comb
- are rigid enough not to warp or bend
- can use starter strips to guide comb building
- can be reinforced for easier comb handling
- can be recessed to prevent lateral movement
But I’ve found that top bar complications don’t add much functionality. Simple top bars are usually the best.
A beekeeper needs a simple, non-bwguyestructive way to access the bees and their comb. Top bars offer this function. Ideally, the bees build one comb, centered down the length of a top bar. Removing a top bar removes a single comb without damaging itself or adjacent combs.
This allows colony management and honey harvesting without destroying the bees or their nest. Top bars once removed, can be replaced, returning a nest to its original configuration.
The wrinkle? Bees don’t need or want any intrusions into their nest. They have no provisions for handling comb that moves or rotates.
Comb is curved and has a variable width. But saws cut along straight lines. So it’s simply not practical to build curved top bars. The bees are as likely to build curved comb across curved bars as across straight ones. So, straight top bars, which are quick and easy to build, are used. And various adaptations and management techniques are use to make them functional.
Straight is a close approximation to brood rearing comb, which is generally straighter, more uniformity spaced, and has less curvature than honey storage comb. But it’s a poor approximation for the wild orientation and spacing found in the honey storage comb.
So, how do beekeepers handle the variable comb thickness? Some use a single broodnest width top bar throughout the hive. Overlapping honey storage combs are cut or moved as a unit, without separating individual top bars. Then they are harvested at the end of the season when ripe.
Others use a slightly wider top bars at 1 3/8″. It’s not ideal for the broodnest. But it’s accepted in the broodnest area and works for most of the honey storage comb.
Using several different top bar widths is a common solution. They vary from 1 1/4″ in the broodnest, to 1 3/8″ in the transition area, to 1 1/2″ or more in the honey storage area.
Another solution involves optimizing the top bar width for the broodnest at 1 1/4″. Then spacers are inserted between top bars when more width is needed.
Since top bar hive comb is attached and supported only by the top bar, it’s imperative that the top bar remain rigid. Any top bar flexure will cause comb failure. Rigidity is a function of top bar length and thickness. To maintain rigidity, longer top bars need to be thicker.
Taller, heavier comb requires a thicker top bar also.
Migratory top bar hives are subjected to the rigors of stacking, rough roads and handling. They need a thicker top bar.
Will the beekeeper set on the top bar hive? Will it be top supered? These situations require a thicker top bar.
Top bar hive beekeepers use some method to center comb-building down the length of a top bar. Most produce a ridge, imprint or starter strip that the bees hang from and start comb-building on. All work some of the time. Some, work most of the time. But none work every time:
- beeswax filled saw kerf
- dribbled/molded beeswax ridge
- foundation starter strip
- wooden spline
- milled ridge
Fixing beeswax based starter strips in a saw kerf with melted beeswax is problematic. If the wax melt is too cool, the strips will fall out at higher hive temperatures. If it’s too hot, the lower portion of the strip will be consumed by the melted beeswax. That results in a starter strip resting on a beeswax filled kerf. These are weak and easily break off. Using plastic foundation strips and not beeswax negates this problem.
Starter Strip Height
Making a starter strip too tall creates problems. When too tall, the bees hang from the starter strip, rather than the top bar, and start building comb from the bottom of the starter strip. Later, they return and attach the comb to the top bar itself. This will guarantee comb failure if the starter strips are fragile or insufficiently attached to the top bar.
Tbh comb is fragile. It’s particularly weak to rotational forces applied perpendicular to the comb. Tbh comb can be much reinforced by incorporating vertical supports which extend down from the top bar. Bees work these reinforcements into the comb as they build the broodnest.
- comb can be handled with one hand
- complicate top bar construction
- are fragile and warp when stored
- hives and reinforcements must be absolutely vertical during comb-building
- bees sometimes build around them
- frustrate comb cutting/honey harvesting
Recessed Top Bars
Most of my top bars, pictured below, have a notch on each end. That allows the top bars to sit squarely down on the hive body. And it prevents them from sliding sideways.
It’s a handy feature, but not needed once the bees start building comb. Then, they will add a small amount of propolis to the ends of the top bars which keeps them from sliding.
Through time, some of that propolis ends up in the notch creating a nuisance. As the top bar hive is worked, the propolis will raise the top bar slightly creating a gap which the bees will fill with more propolis. Eventually, the notches will need cleaning which is a pain.
And it complicates cleaning the top bars when harvesting comb from the hive. With a single flat surface, one pass of a hive tool yields a clean top bar. With notches, there’s a lot more messing around to get them clean.
It’s better to learn from my mistake and not follow my example. Skip the notch.
Simple Is Best
After trying many top bars, I found simpler is better.
- they’re easier to build
- more flexible to use
- easier to clean
Once a tbh beekeeper learns how to manipulate and manage top bar comb, most of the advantages for building a complex top bar are lost.
And since the bees construct curved, variable width comb. And even the most enhance top bar design uses a straight top bar, some form of comb management is still needed to keep the comb workable.
Top Bar Examples