Hive Covers and Roofs

The hive cover and hive roof are two separate parts that close off the top of a framed hive: the inner cover (crown board), sitting directly above the frames, regulates the climate inside the hive, while the outermost outer roof keeps out rain, sun and wind. In winter, what kills a colony is often not the cold but a top closure that leaks or drips condensation.

What parts make up the top of the hive?

In modern framed hives (Langstroth, Dadant and similar), the top closure usually has two layers. Some beekeepers add an insulation layer or a feeder in between; but the basic pair is always the same:

1. Inner cover (crown board): sits directly on top of the frames' top bars. It stops the bees from building propolis and comb straight onto the roof, and separates the air inside the hive from the outer roof.
2. Outer roof (hive roof, lid): goes on top of the inner cover and is the hive's shield against the weather.

Some beekeepers use a cloth or plastic sheet instead of an inner cover; the material properties of these flexible covers are described on a separate page, under the heading "Hive covers (beekeeping supplies)". This page focuses on the crown board and roofs as fixed parts of the hive.

What does the inner cover (crown board) do?

The inner cover is the "ceiling" of the hive. Its jobs look small but are decisive:

• Stops the roof from sticking: bees fill the space at the top with propolis. Without an inner cover, the outer roof gets glued to the hive; opening it means jarring and angry bees.
• Buffer air layer: the outer roof heats up in the sun and gets cold in winter. The air and cover in between keep these temperature swings away from the cluster.
• Feeding hole: most crown boards have a hole in the middle; fondant, a syrup container or an inverted jar can be placed over it.
• Bee escape slot: the same hole, when fitted with a bee escape (one-way passage), is used to clear bees from the super before harvesting.
• Easier inspections: when the outer roof is lifted, the bees are still under the cover; giving smoke first and then lifting the cover makes for a calmer inspection.

What to look for in a good crown board

• Thanks to the rim, a bee space (about 6–9 mm) should remain between the top bars and the cover. If the gap is larger, the bees build comb in it; if smaller, you will crush bees.
• It should sit on the hive without gaps and not be warped; a warped cover opens the door to robbing bees and moths.
• The feeding hole should be closable (a wooden plug, a mesh cover).
• Plywood or well-seasoned solid wood; cheap chipboard that swells with moisture soon deteriorates.

What types of hive roof are there?

The most critical point in winter: how do you prevent condensation?

The winter cluster produces both heat and moisture. Warm, moist air rises and condenses when it touches a cold ceiling. If this water drips onto the cluster, the bees get wet, heat loss multiplies and the colony can be lost. Water running down the sides and back wall makes the combs go mouldy. The solution has two parts:

• Top insulation: placing a non-absorbent insulation board on top of the crown board, or using an insulated roof, keeps the ceiling warm; condensation then forms away from the cluster, on the cold side walls.
• Controlled ventilation: a small escape route is left for moist air (covering the hole in the crown board with mesh, or a small upper ventilation gap in the inner cover or roof).

Insulation alone traps moisture, ventilation alone lets heat escape; the two must be considered together. Also, if the hive tilts slightly forward, condensed water runs out through the entrance.

How are the roof and cover used in summer?

• Light colour: a roof painted white or a light colour, or clad in shiny metal, heats up less in the sun.
• Shade: in very hot areas, placing a plank, matting or a shade over the roof stops the beeswax softening and the hive overheating.
• Ventilation: in a strong colony and during a honey flow, the hole in the inner cover can be kept open, covered with mesh; but once the robbing season starts, this route should be closed.
• Feeding: syrup and fondant are given over the crown board; there must be no gap around the container that bees can reach from outside, or robbing will start.

Wind and transport: how is the roof secured?

A roof blown off in a storm leaves the colony exposed to rain and cold within a few hours. Ways of securing it:

• Placing a heavy stone or brick on the roof (the most common method; but the stone must sit on a level surface where it won't slide).
• Strapping the hive and roof to the stand or floor with a hive strap.
• In migratory beekeeping, making the flat lid, floor and boxes into a single block with transport clips or straps.

How is a hive roof maintained?

1. Go over the roofs every autumn: look for cracks, holes, lifted metal edges and loose nails.
2. Check the corners of the metal cladding; water usually seeps in through the corner folds.
3. Paint a wooden roof with a bee-safe exterior-grade preservative; apply paint only to outer surfaces, and don't paint the underside of the inner cover or the inside of the hive.
4. Scrape propolis and comb remnants off the crown board with a hive tool; keep the mouth of the hole clear.
5. Replace a warped roof that cannot be straightened. A leaking roof costs far more than a new one.

Common mistakes with hive covers and roofs

• Putting the inner cover on upside down: the bee space ends up on the wrong side, and the bees build comb in between or glue it to the top bars.
• Leaving a roof held down by a single stone on a windswept hilltop.
• Leaving insulation material that gets wet in winter and doesn't dry on top of the cover.
• Mixing roofs of different types and sizes; a roof with gaps lets in robbers, hornets and rain.
• Painting the inside surfaces of the hive and the underside of the cover, or applying chemical preservatives.