Here’s a Google Sketchup based plan for this hive:
I’ve come up with my version of a vertical top bar hive using the following criteria:
- designed for prolific bees in a northern climate
- tall enough for small cell sized comb development
- one box per season rotation
- square configuration
- interchangeable cover and bottom
- self spacing top bars
- comb spaced at 1 1/4″
- conventional construction material
- easy construction with minimal cuts/parts
- optimal material use
Warre’? Not Quite.
This design is loosely based on the principles of the Warre’ hive.
- it’s larger and taller
- the walls are thinner
- and a simple migratory style cover/bottom board replaces the Warre’s elaborate insulated cover
Here’s why this is a better design for my beekeeping.
In my horizontal top bar hives, the bees initially draw out comb about 12 to 14 inches wide. Then they come back later and finish the rest of the comb’s width with drone comb. An optimum minimum comb width might be in this size range. So, I’ve set the hive width there.
Brood comb cell size decreases at about a 1% rate down it’s height in a top bar hive. To get an effective small cell sized core requires comb at least 9 inches tall. So, I’ve set the box height beyond that.
My bees consistently overwinter in a cluster that’s about 11 ” to 13″ in diameter. So, that’s about the minimum interior width of my hive. And I prefer to have at least one unoccupied comb between the cluster and hive’s sidewall.
In my climate, a prolific colony can function and over winter best in a three deep Lang hive. There’s enough space for the cluster. And enough room for food so that supplemental feeding isn’t required. That’s about 7800 cubic inches. A taller, square, hive would need at least four boxes for an equal volume. That’s a larger hive than used for Europe’s conservative native bees which the original Warre’ design was design for.
My cover violates several of the basic principles for the insulated, ventilated covers of the Warre’ hive. But my winter condensation observations show this cover is sufficient for my climate. Need more insulation? Apply blue construction foam panels externally. And if additional sealing is needed above the top bars, place a canvas/plastic cloth underneath the flat cover.
I’m tossed about top bar thickness. I’d prefer a thin, narrow one that would minimally impact comb building and broodnest. But such a top bar would flex and cause comb failure if not handled carefully. I’ve opted for one that’s thinner than what I’d use in a top bar hive, with its longer, heaver, more frequently worked comb. But one that’s robust enough to handle comb management.
The flat cover/bottom boards are convertible and stack-able which is almost a necessity for a migratory hive.
Glue two 1″ x 8″ x 3/4″ pieces of lumber together to form the building stock. Cut the sides, cover and bottom from it. That allows a square hive, 14 1/2 inches on a side.
The front and back have a rabbit cut in them for the top bars. Fasten a lifting cleat to the front and back of every box.
Cut top bars from 3/4″ stock. They are 7/8″ wide and 13 5/8″ long. Two finish nails, driven to the proper depth, give a 3/8″ space between the bars and allow self spacing. Cut a thin notch down the center for a foundation based starter strip or a bead of beeswax.
Eleven top bars on 1 1/4″ spacing will make a tight fit without any working room. This is the configuration I’ll probably use as I don’t plan on manipulating comb if I don’t have to.
Ten top bars spaced at 1 1/4″ will allow a half comb width of free space on each side. This is the configuration I’d use if I used conventional comb management practices and needed some working room.
And different comb spacings can easily be handled by varying the depth the finish nails are driven into the top bar. Ten bars make a tight fit at 1 3/8″ spacing. Nine bars will provide working room.
The cover and bottom are identical migratory type components. They have 3/4″ wood strips around their edges. The bottom lacks a 3/4″ wood strip across the front, which provides the entrance. Tack the front strip in place. Then it can easily be removed or affixed converting a cover to a bottom or vice verse.
End grain is exposed on these hive parts. But I found that the conventional ways to cover them actually traps moisture causing them to rot. So, I’ve left them exposed.
With the minimal management needed for this hive, nail both the cover and the bottom to the hive body with galvanized roofing nails.
Management is simple. At the end of the season, heft the hive to find if it’s heavy enough. If so, remove the top box and harvest its’ honey. Then, return the empty box to the bottom of the hive. If the hive’s not heavy enough, feed it. Or place a spare feed box on top.
I haven’t built or managed bees in this hive. But it’s the most interesting project on my list. I’ll let you know how it goes.