Motivation for the removable screened bottom board

I wanted to make a screened bottom board to facilitate mite monitoring and sugar dusting. I also wanted a bottom board design that allowed more space under the hive for winter. My main motivation for designing this variation of the screened bottom board is so I can clean out dead winter bees with greater ease, and worry less about the bottom entrance getting clogged up with dead bees.

The Screen

Screened frame removed A framed screen was created by gluing together a sandwich of 1/8 inch hardware cloth and wooden slats.

Tips. If you can find it, use stainless steel hardware cloth as it will hold up better to any formic acid exposure that may happen while performing mite treatments. Of course, If all you can find is galvanized, removing the screen during treatments is an option.

Rabbets were cut into the side walls of the bottom board structure to support the screen.

bevel on framed screenInspired by the concepts in Walt Wright's propolis Article, a slight bevel was cut into the sides of the framed screen in the hopes of minimizing the accumulation of propolis between it and the frame rest.

The back of the bottom board

back of bottom board with hinged flap opened.The back of the bottom board is comprised of two pieces of wood:

The top piece:

  • Is screwed in place.
  • Blocks the area containing the screen and the space above it.

The bottom piece:

  • Is hinged to the top piece for the purpose of allowing easy access to the tray when performing mite counts.
  • When closed, it prevents bees, mice and wasps. from accessing the area between the screen and the tray.
Caution. Distance between the screen and the tray is two inches to reduce the possibility of varroa climbing back up into the hive. I've seen references to 1 and 5/8 inches being sufficient, but some say to use two inches. I decided to play it safe.

Bottom view of framed screen.The concept is that during the fall, when winterizing the hive, the screened frame can be removed from the bottom board while all the hive boxes remain in place. My hope is that the screened frame can be pried up from the area inside the hinged flap in order to loosen any propolis. The top portion on the bottom board's back can then be unscrewed and removed to allow the framed screen to slide out. Thus converting the hive to a simple solid bottom board.

The Tray

debris on bottom board trayThe tray is just a simple piece of corflute that slides into a groove in the side walls. I run eight frames to a box. The above photo shows the screened area is large enough to allow debris and varroa to fall through from spaces between and around all eight combs.


Entrance with reducers in placeThe framed screen extends above the height of the landing board so that entrance reducers are prevented from being pushed too far back into the hive.

In the winter, when the screen is removed, the entrance becomes taller. changing from 14mm to 21mm tall.

Note: A 14mm entrance height on my modified warré hives works out to a total entrance area around 40cm2. That's about three times the entrance area preferred by swarms looking for a home in the wild, however, 40cm2 is roughly equivalent to the entrance area found on a langstroth hive using a 3/8" high opening. Perhaps the large difference in feral vs managed entrances is based on the fact that it's not unusual for managed hives to reach a volume that is three times greater than that of the typical colony in a tree cavity?

As my intended mouse guard is just a piece of hardware cloth wedged into the entrance, I suspect the 21mm tall winter opening will allow the bees more room to navigate the tiny gaps of the hardware cloth.

Visual patterns

pile of bottom boards
The above photo shows a stack of the first four entrances I built. I painted each landing board with a unique visual pattern in the hopes that it would help the bees in recognizing their own hive and therefore reduce the drifting of bees between different hives. This was inspired by the concepts discussed in Tautz's book The Buzz about Bees: Biology of a Superorganism. The idea is that unique patterns are more useful to bees than simply painting each hive a different solid colour.

Tips. The bees won't care if the designs are as ornate as those in the photo above. Simple variations will do. The key differences, from top to bottom, between the pictured bottom boards are:

  • A horizontal line with lots of vertical lines
  • A small semi-circle on the upper edge with some radial lines
  • A big semi-circle on the lower edge
  • Three circles with a few horizontal, vertical and radial lines

Other uses for the framed screen

The framed screens may also be used to serve other purposes. For example, if I want to over-winter a weaker hive stacked on top of another colony, I can place the framed screens from both colonies between each other like one might ordinarily do with a double-screen board.

Testing it out

I've added these to 5 hives for the 2015 season. I'll update here once I decide if the experiment was a success or a failure.


Do I need a queen excluder?

The simple answer to the question is no you don't need a queen excluder. In fact, I prefer not to use them most of the time. Why I feel that way is best explained by this video where you can see very clearly that some worker bees are struggling to pass through an excluder.

They may not all be as restrictive as the model in this video, but I believe it illustrates why you will find many references to beekeepers calling it a 'honey excluder'.

But won't I end up with brood in my honey?

Probably not. The queen wants to lay a tight compact brood nest and the bees prefer to store honey above the brood. Even if a prolific queen extends the brood nest into a honey super, the worker bees will likely be eager to fill this space with nectar again once the brood hatches.

It is possible, in some situations, that the bees will create a narrow tower of a brood nest up the middle of many boxes. Circumstances where this is more likely to occur include:

  • During a heavy honey flow, if the brood boxes become honey bound, and the queen is desperate for more laying space
  • When extra boxes are provided early, the bees may choose to expand upwards rather than fully filling out the width of each box

Dearth's can also complicate things. If the bees are eating more honey then they are bringing in, they will start moving the brood nest upwards as they eat through their stores.

There are some uses for them

Some instances where a queen excluder can come in handy include making splits, raising queens, and locating a particularly elusive queen.

I've seen beekeepers use queen excluders without any problems

I've worked bee yards for years where excluders where used by default. The bees still stored honey in the supers and it did guarantee that the queen stayed below. We found it useful to put the excluders on early to give the bees a chance to get used to them before the supers were really needed. We also always provided an unobstructed path to the honey supers via an upper entrance.

There are a few things you can with your standard langstroth roofs to help keep the bees comfortable during a heat wave. There are also a few design modifications well worth considering when building your own roofs that may further protect your bees from the intense mid-summer sun.

Can't the bees just fan the hive to keep things cool?

Yes, they will certainly try, but as amazing as they are, even bees have their limits. If it gets too hot they will shut down brood production, and in extreme situations it is possible to lose colonies.

To get a sense of how hard your bees are working to keep cool, it's relatively easy to place a thermometer at your entrance(s) to gauge the temperature of the air being pushed out of the hive.


Keep in mind brood rearing requires a temperature in the 33-36°C (91 - 97°F) range. If your entrance temperatures are significantly above that, you may wish to take the temperature near the brood nest to see if they are winning the climate control battle.

Even when things are not too extreme, why not take a few simple steps that might save your bees from wasting time and energy?

Creating ventilation

Adding an upper entrance and tilting a telescoping cover back is certainly a simple way to offer some heat relief to a colony.

langstroth upper entrance with lid tilted back

Painting metal roofs white

With the ambient temperature at 33.8°C (92.8°F), a plain metal covered roof was a very hot 46.1°C (115°F), while a metal rooftop with a coat of white latex paint was 38.3°C (101°F):

temperature of painted metal hive roof

Providing shade

In my region, it is generally advised to locate your bees in full sun. For those living further south, the conventional wisdom is to try and provide mid-day shade. If, like me, you have chosen a full sun location, you can provide shade only when the temperatures are unusually hot.

A simple, if temporary, way to add shade is to lay a few tree branches on top of your hive. I chose branches from a tree species known to be invasive in my area.

Using branches to provide the bees a bit of shade

Within a short period of time, this dropped the temperature of my painted roof down 3.4°C to 34.9°C (95°F).

Of course, the leaves will soon dry out and shrivel. If you are experiencing an extended heatwave, you may wish to consider a more durable solution.

Build a double-level roof.

The idea here is that the top-level creates a solar shield that effectively shades the bottom level, while simultaneously creating an air gap through which a breeze can pass, thus minimizing thermal conduction of heat downwards into the hive.

With the ambient temperature at 33.7°C (92.7°F)

Ambient temperature near the beehive

The metal covered, upper-level of the roof was 46.7°C (116°F), while the temperature below was a cool 31.4°C (88.5°F)

Temperture under a 'warre' style beehive roof with solar shield

The inspiration for this style of roof comes from the warré hive.

Build your roofs with corflute under the metal

Corflute is the kind of material election signs are usually printed on. The air pockets in the material help insulate and minimize thermal conductivity.

Using an old printing press sheet and coflute to protect the beehive from rain and heat

Use a Quilt or other form of insulation

A warré style quilt helps keep heat in during the winter, but it also helps keep heat from the sun out of the hive during the summer.


The thermometer I used throughout this post is a regular digital thermometer that one might use in a kitchen.

The main quality you are looking for in this tool is ability to adjust to ambient temperature relatively quickly. You can find one here on Amazon.

I used inspiration from the colony transfer section of this page and the simple D. Coates nuc box plan as the basis for my lang to warré transitioning nuc box.  I need to put this box on top of a warré box so I reduced the height of the walls a 1/2 inch to compensate for the height of the floor that I am removing from the D. Coates design. The only other modification to the base of the design was to omit an entrance in this box. Instead, the warré box will sit on a regular bottom board entrance.

lang to warre nuc box - nuc with wings

I did add a floor just to the section that hangs over the side of the warré in the back and front. I also glued and nailed 'wings' to the side of the nuc which extend to the edge of the warré box. The wings serve as a roof for the section of the warré the nuc does not cover.

The wings are slightly asymmetrical, this was done in order to position the nuc box on top of the warré such that the gaps between the langstroth frames will line up with gaps of the warré frames. The hope is that this will make it easier for the bees to move between the two boxes.

lang to warre nuc box - matching the frame gaps

I made a five frame nuc box, but around my area they typically sell four frame nucs. So, in addition to the frames I receive from the bee breeder, I will place one of my smaller warré frames in the nuc box. To do this I simply used wire from twist ties to strap a frame to a wooden slat that fits the length of the langstroth. Once the bees start drawing out this frame I will be able to remove the wooden slat and place the frame in the box below to encourage them to move down.

lang to warre nuc box - a transitional frame

On top of the plywood roof I added an old printing press plate that I sourced from a local publisher and a discarded plastic corflute sign board (similar to that used for election signs). The sign board has air pockets and will hopefully slow the heat from the sun on the metal from conducting through the roof. The printing press plates are simple to work with. I cut it to size with regular scissors and staple it in place with an ordinary staple gun.

Using an old printing press sheet and coflute to protect the beehive from rain and heat

The plywood was scrap from neighbourhood carpenters, and the paint came from the municipal household hazardous waste dump, thus the cost of making this box was virtually nothing.

lang to warre nuc box

I'll be eager to get the nuc off the hive and give them a proper roof, but am confident this box should make for a smooth and simple transition between the different shaped hives.

Update: I've now successfully encouraged bees to move down with this method.

warré seed frame almost filled out

You can see the nuc transition box in practice here. The main issue I had was that they built comb on the side of my frames that would need to be broken off. In subsequent attempts I used a wooden block to prevent this.

IMGP18712015 update: While the wooden blocks were a significant improvement they would still build little combs between the frame and the blocks and it was cumbersome to untie the frame. So I made the blocks with only a 'bee space' between it and the frame and a little notch at the top of the block acts as a frame rest:

Photo via flickr.

Each wooden block is attached using a single screw, allowing the block to turn and making it relatively easy to remove the propolized frame.

Photo via flickr.

My current approach is to try to move frames down, and place new frames back in the nuc as long as they are raising brood in the nuc. As comb building is prioritized at the top of the hive, and I already have drawn combs up here, I found it to be a good way to keep getting straight combs. I stop adding new combs once I no longer have a brood frames in the nuc box as they bees like to make honey combs bulge out into any available open space.


Walt Wright » Propolis – Another 5 Percenter

Walt Wright Suggests constructing the hive in such a way as to reduce the need for the bees to add propolis will allow them to spend that much more time collecting honey.

PropolisPhoto by: OBA TTP / CC: Attribution-NonCommercial-NoDerivs License

He suggests trying to make the hive boxes as level as possible, as well as shaving the end of the frame that rest on the rebates down to a sharp angle so as to reduce the point of contact between the frames and the hive body.


Nestduftwärmebindung - Johann Thür's concept of retaining nest heat and sent

David Heaf's translated excerpts from Johann Thür work asserts the importance of heat and smell for the bees. Thür has scathing criticism for the use of frames. He claims the extra space around the frames makes it easier for the warm air of the hive to escape the nest and increases stress on the bees.

In the spring we often find that our hives have had to cope with excess moisture building up over the winter months. When it's bad, winter moisture problems will lead to mouldy comb and cold water dripping onto and chilling the bees.

mouldy beeswax comb

The typical cause?

The bees themselves will produce a great quantity of moisture just by breathing. Warm moist air rises, spreads along the top of the hive, comes into contact with the colder side walls and inner cover, condensation forms and drips back down into the hive.

mould in the hive

The simple and oft suggested remedy to this problem is to provide some form of upper ventilation. Some swear by the top entrance, but so far that option still seems a little drastic to me as so much upward moving heat is lost at the same time as the moisture.

So how do we reduce the moisture without losing the heat?

The short answer is insulate and absorb. You want to give the moisture somewhere to go and try to minimize the temperature difference between the hive walls and the cluster. It's been suggested this problem might be less likely to occur in a wild hive where the tree wall is thicker, there is much more than a thin layer of wood above the hive and that a tree might better absorb moisture than a plywood inner cover. The moisture absorbing qualities of a tree cavity hive are largely speculations as far as I know, and likely not true if we accept the research out there that suggests bees propolise the inner surfaces of trees.

beehive humidity box

So how can we attempt to emulate those conditions with modern day man-made hives?

Aside from insulating our hives, we have started adding ventilation boxes on top of our hives. Essentially a short box filled with straw, wood shavings or other absorbent material. The side has screened holes(keep the mice out) and burlap is stapled to the bottom.

Adding a vent box to beehive

In the photos you can see we placed it above an inner cover with a vent hole, but it could be placed directly above a brood box.

beehive ready for winter

We used these during the 2011/2012 and 2012/2013 winters and had dry hives in the spring. In a few cases there was a bit of dampness in the ventilation box.

2013/2014 was a particularly cold winter. I was no longer using lang hives, just warré hives with quilt boxes placed on top of propolised top-bar cloths. I checked the bottom of a few quilt boxes serveral times over the course of the winter. Though I didn't find any  moisure build up, it was interesting to discover that on warmer sunny days, the temprature at the bottom of the quilt box would be a few degrees below ambient.

2014/2015 Another brutaly cold winter. One colony had been blown over during an intense wind storm in early November. In the frantic process of putting the hive back together again, the proplised top-bar cloth was removed. The hive overwintered with only the quilt directly on the top bars. In the early spring the upper 3/4 of saw dust and straw was a little damp as was the roof. This was replaced with fresh dry material.

More on vent boxes or quilts

Those familiar with the warré hive will without doubt find this very similar to the quilt which is traditionally used year round to help stabilize the climate within the hive. Information on design variation and precursors to the warré quilt can be found here.

Matt at beethinking.com has written a some data on the use of a quilt on a langstroth showing how its use stabilized temperature fluctuations in the hive.


Dave Cushman's analysis of bee space

The discovery of the bee space is said to be the foundation of modern beekeeping.

For a long time I thought it was a very simple matter and didn't give it much thought, but as I've been attempting to build my own hives I've discovered there's a range given for exactly what the bee space is (6mm - 9mm or 1/4"-3/8").

I've also learned I need to account for wood shrinkage and different parts of the hive need different kinds of space (ex. between boxes or between combs).

In the linked article Dave Cushman's provides a great overview of important space dimensions used in different pieces of hive equipment.