A top bar hive (TBH) represents a distinctive approach to beekeeping, utilizing a long, horizontal box structure rather than the vertical, modular boxes of the common Langstroth design. This hive style is often chosen for its simplicity and the ability it offers for a more natural beekeeping experience, where bees draw their comb freely without the need for pre-formed foundation sheets. Unlike the Langstroth, a top bar hive requires no heavy lifting, as inspections and harvesting are done by removing individual, lighter bars instead of stacked supers. The design philosophy is to provide a home environment that closely mimics a natural tree hollow.
Sourcing Materials and Tools
Building a durable hive begins with selecting the proper materials, prioritizing untreated wood that will not harm the colony. Western Red Cedar and Cypress are favored for their natural resistance to rot and weathering, but pine is a more economical option if its exterior is properly sealed. You will need lumber for the side walls, end pieces, the bottom, and the numerous top bars.
Hardware includes exterior-grade wood glue and stainless steel or brass wood screws for secure joinery that resists corrosion. For tools, a table saw or circular saw is needed for precise, straight cuts, especially for the top bars and angled components. A drill, a framing square, and clamps are also necessary to ensure everything aligns correctly during assembly. If a screened bottom is part of the design, small-gauge hardware cloth is required.
Understanding Key Dimensions and Geometry
The functionality of a top bar hive relies on “bee space,” the precise gap of approximately 3/8 inch (about 9.5 mm) that bees naturally leave for passageways. If a gap is smaller, bees will seal it with propolis; if it is larger, they will fill it with unwanted “burr comb.” This principle dictates the width of the top bars, which should be 1 3/8 inches (about 35 mm) wide to ensure the correct center-to-center spacing for the hanging combs.
The unique trapezoidal shape of many top bar hives, known as the Kenyan style, serves a structural purpose rooted in bee behavior. The side walls are angled, often at 60 degrees to the horizontal, creating a cavity that narrows toward the bottom. This narrowing discourages the bees from attaching their comb to the hive walls as they build downward, a common issue in straight-sided hives. Maintaining this taper is important for allowing the beekeeper to easily remove a comb for inspection without tearing it from the side walls.
Step-by-Step Hive Body Assembly
With all pieces cut to size, the hive body assembly begins by joining the side walls to the end pieces using waterproof wood glue and screws. Butt joints are common, but reinforcing the corners with internal blocks or rabbet joints adds structural integrity. Ensure the top edges of the side walls are parallel and level, as this is where the top bars will rest to form the hive’s ceiling.
If using a screened bottom, the hardware cloth is secured to the underside of the box, allowing for ventilation and mite control. A solid bottom board is glued and screwed into the base of the frame. The hive must be raised off the ground to protect it from moisture and predators, so the four legs are typically bolted to the end pieces. The height should be comfortable for the beekeeper, often resulting in a hive that stands about waist-high. Bolting the legs provides a sturdier base that can withstand the weight of a full colony.
Constructing Top Bars and Final Preparations
The top bars must be cut to the precise width of 1 3/8 inches to maintain the necessary bee space. To guide the bees in building straight comb, each bar needs a comb guide along its centerline. This guide can be created by routing a shallow groove and inserting a thin wooden spline, or by attaching a small triangular piece of molding. Encouraging the bees to start correctly is important, as crooked comb can quickly spread, making inspections impossible.
Once the hive body is assembled, the exterior should be finished to protect the wood from the elements. Applying a light-colored, non-toxic exterior paint or a natural oil finish like linseed oil will prolong the life of the hive and help reflect excess heat. Ventilation is managed by drilling small entrance holes, typically two or three one-inch holes positioned about two inches up from the bottom at one end of the hive. The hive must be positioned on a level surface in a location that offers protection from harsh winds and is easy for the beekeeper to access without disrupting the flight path of the foraging bees.