Frames and Foundation

A frame is the wooden or plastic surround that holds the comb and allows it to be taken out of the hive one at a time; foundation is the thin sheet of beeswax (or plastic) embossed with hexagonal cell bases that is fitted into the frame. Together they form the basis of modern framed-hive beekeeping: inspections, harvesting, splitting and disease control are only possible when the comb is movable.

What parts does a beehive frame consist of?

A standard frame consists of four bars:

• Top bar: Hangs by the lugs at its ends (frame lugs) on the rebate in the front and back walls of the hive. The foundation is usually fixed in a groove in the top bar or under a wedge strip.
• Side bars: The two vertical edges of the frame; the holes for the wires are in these bars. On Hoffmann-type frames the upper part of the side bar is widened, which keeps the spacing between frames automatically.
• Bottom bar: Can be one piece or split in two; the lower edge of the foundation is fitted without touching this bar, leaving a small gap.

A bee space (about 6–9 mm) is left between frames and between the frames and the hive walls. Bees fill narrower spaces with propolis and build comb in wider ones. The whole design of the framed hive is based on this measurement.

What types of frame are there?

By size

Within the same hive system there are frames of different heights: deep frames for the brood box and full-depth super, shallow frames for a half-depth super. Frames from different hive systems (Langstroth, Dadant and local types) do not fit each other. Sticking to a single system in an operation makes exchanging frames and managing stock easier.

By material

• Wooden frame: The most common type; it can be wired, repaired, and cleaned by boiling and scraping.
• Plastic frame: One-piece frames with integral foundation. No wiring is needed and they do not break in the extractor; however, some bees may be reluctant to draw out the plastic surface, and a thin coating of beeswax on it reduces this reluctance.

By spacing method

Hoffmann-type frames with wide side bars keep their own spacing. With straight-sided frames, spacing is set by notches in the frame runner, plastic spacer ends or by the beekeeper's eye. This topic is covered separately on the "In-hive frame spacers" page.

What is foundation for?

Foundation is a guide that shows the bees where to build comb and with what cell size.

• Straight comb: The comb stays inside the frame and flat; frames can be exchanged between hives.
• Control of cell size: Foundation embossed with worker cells (cell diameter about 5.2–5.4 mm) limits the proportion of drone cells (about 6.2–6.9 mm).
• Saving effort: Bees consume honey to secrete wax; foundation provides wax to start with and speeds up comb building.
• Strength: Foundation supported by wires gives comb that resists breaking, especially in the extractor.

How do you wire a frame and fit foundation?

Fitting foundation taut and flat is the most often skipped but most decisive detail. Foundation fitted loosely or crookedly turns into crookedly drawn comb, and crooked comb destroys the interchangeability of frames, which is the whole benefit of the system.

1. Prepare the holes: Wire holes are drilled in the side bars; small metal rings (eyelets) can be fitted in the holes so the wire does not cut into the wood.
2. Tension the wire: Stainless or tinned steel wire is run horizontally between the side bars and tensioned until it twangs when plucked with a finger. Slack wire is useless.
3. Fit the foundation: The sheet is fixed in the groove of the top bar or under the wedge strip; a small expansion gap is left between its lower edge and the bottom bar.
4. Embed the wire: The wire is heated and embedded into the wax. For this, a device that heats the wire with low-voltage electricity or a hand-held spur embedder is used. The wire should be embedded in the middle of the sheet without cutting through the wax.
5. Check: The sheet should be flat, without waves, and centred in the frame.

Foundationless frames and starter strips

Some beekeepers do not use foundation and fit only a thin strip of wax (starter strip) or a wooden guide strip to the top bar; the bees build comb with their own cell size.

• Advantage: Less risk of chemical residues and adulterated wax, and the bees choose their natural cell size.
• Disadvantage: The proportion of drone cells can increase, the comb breaks more easily in the extractor, and if the hive leans to one side the comb strays out of the plane of the frame.
• Practice: The hive must be level from side to side, and the foundationless frame should be placed between two drawn combs.

Why does the source of foundation matter?

Beeswax retains fat-soluble substances. Residues of some acaricides used in hives can remain in wax for years, and commercial foundation is a mixture of wax from many sources. In addition, adulterated foundation mixed with cheap substances such as paraffin or stearin can cause bees to build defective comb and brood to fail to develop.

• If possible, have foundation made from your own cappings wax; a closed wax cycle is the surest way to limit residue build-up.
• When buying, ask whether the wax is pure beeswax and where it comes from; be wary of sheets that are very cheap, odourless, or shiny and slippery-looking.
• Wax from diseased hives should not be made into foundation again without adequate heat treatment.

Comb renewal and the drone frame

Old comb accumulates pathogens, chemical residues and cocoon remains; the cells become narrower over time. Renewing some of the brood combs every year is a common and recommended practice. Dark brood combs are removed first; light-coloured super combs can be used for longer.

A drone frame (drone brood frame) is a frame with no foundation, or with only a strip at the top. The bees mostly build drone cells in the empty space. Because varroa prefers drone brood, the comb is cut out and discarded after the drone brood is capped and before the drones emerge. Timing is critical: if you are late, the mites emerge along with the drones and the method works in reverse. This method is a supporting part of varroa control and is not enough on its own.

Storing frames and combs

• Drawn comb is valuable; it saves the bees a great deal of time the next season.
• To protect against wax moth, combs are stored in a cool, light, airy place with air able to circulate between them; a short spell in a cold store or deep freezer kills moth eggs.
• Dark brood combs are not kept in storage for long; the moth likes these best.
• Empty frames fitted with foundation are stored in a closed box, protected from dust and mice.

Common mistakes

• Using slack wire or crooked foundation.
• Giving the brood box many sheets of foundation at once; a weak colony struggles to draw them.
• Mixing frames from different systems.
• Never renewing comb.
• Not cutting out the drone frame on time.