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How to build a slatted rack

I never go without a slatted rack in my beehives, and I extoll the virtues of them every chance I get. David Manning, a beekeeper in Missouri, makes some seriously good-looking slatted racks that you can see in the photos below. For those of you who are handy in the woodshop, David has graciously shared his method in the following write-up.

Thank you, David, for taking the time to share with us.

Editor’s note: materials list updated 6/9/15.

Materials List

(2) ¾” x 2¼”x 19⅞” for side boards
(2) ¾” x 2¼” x 15½” for front and back board
(1) ¾” x 4¼”x 15¼” for shelf at front of rack
(10) ¾” x ¾” x 15” slats

Cutting dados on pieces

  1. On the ends of both 2¼” boards cut a dado ⅜” x ¾”. These front and back boards will be nailed to the end of the side boards making the side dimension a full 19⅞”.
  2. On the two front and back pieces cut a dado ¼” from the top of the 2¼” board. The dado needs to be ¾” wide by ¼” deep.
  3. On one of the 15¼” sides of the shelf board cut a ⅜” dado ½” deep the full length of the board, making sure that you have 3/16” on each side of the dado. One end of the slats will fit in this dado.
  4. On the two side boards where the shelf will set in a dado, a ¼” x ¾” dado will need to be cut ¼” from the top of the board the width of the shelf board – 4.0 inches. There are two ways of accomplishing this, dado past the 4 inch so that you have a 4 inch x ¼” dado cut with the curved cut beyond the cut. The second way is to cut the dado 4 inch long and using a chisel, remove the part of the dado that needs to be cleaned out in order to have a full 4 inches.
  5. On one end of the ¾” x ¾” x 15” slats, set up a dado blade to cut a 3/16” wide x ½” deep area from opposite sides of the same end of the slat. This should leave a joint on the end of the slat that has a centered ⅜” x ½” area. This is the end that will fit in the ⅜” x ½ “deep dado on the shelf board. The other end of the slat stays ¾” x ¾” and fits in the ¾” dado in the back 2¼” board.

Spacing of the slats in the frame

The purpose of this slatted rack is to have the 10 slats line up with the bottom of each frame in the brood super. To achieve this, the two end slats, #1 and #10, those closest to the sides, need to be spaced so that there is a 5/16” space between the slats and the side board. The remaining 8 slats will have an 11/16” space between each of them.

Securing the slats to the shelf board and the back board

  1. Using Titebond III Waterproof wood glue put glue on edges of boards that will come in contact with another board. In other words, any where there is a dado.
  2. Using 5/8” brads or brad nailer with 5/8” brads or staples, place the brad 5/16” from the edge of the shelf board where the slats mate with the board.
  3. On the outside of the back board draw a line 5/8” line all the way across the length of the back. Place a 1½” brad on the line and centered on a slat that has been correctly spaced.

If your brads are countersunk, on the outside of the frame, fill with wood putty, sand, and then put several coats of sanding sealer on the outside of the assembly that will be exposed to the weather and on the top and bottom edge of the outside frame.

Apply primer and several coats of good exterior paint. I use an exterior paint that the primer and paint are combined.

David Manning
Sparta, Missouri

For more on slatted racks, see:

How to use a slatted rack

Slatted racks: how should the slats be arranged?

Hive five: the best ventilation equipment


The top of the slatted rack is the shallow side. © David Manning.
The bottom side of the slatted rack is the deep side. © David Manning.
The end of the slatted rack with the crosswise shelf goes on the front of the hive, above the entrance. © David Manning.
A complete hive with the slatted rack in place. © David Manning.
The bees are happy with it. © David Manning.


Bovard rack? Really?

The following comment came yesterday in response to the post, “How to use a slatted rack.” I’ve decided to answer the allegations one by one.

Your comments about slatted racks is inaccurate. First the original designer was a man in Hawaii by the name of Bovard back in the 1960s, hence Bovard Racks was the original name.

I don’t see how it’s inaccurate to call a rack with slats a “slatted rack.” Once upon a time, the old-fashioned slatted rack with crosswise slats was referred to as a “Bovard rack.” But the original idea for a slatted resting place below the brood chamber was developed by Dr. C. C. Miller in 1900 and refined by Carl Killion in 1950. Brovard merely came up with a way to build the device in one easy-to-use piece.

Although modern slatted racks maintain the 4-inch wide board in front (conceived by Killion), the slats now run parallel to the frames instead of crosswise so they can be used effectively with screened bottom boards. With the change went the name, and the current rendition of slatted racks are called—wait for this—slatted racks. I invite you to look at the ones for sale at places like BetterBee, Brushy Mountain Bee Farm, or Ruhl Bee Supply.

In any case, the subject of the post on which you are commenting is how to use a slatted rack, not how to name one.

Second, the wide board in the front of the hive directs any incoming air to go up through the cluster so reducing cold air going up past the cluster. The strips are placed crosswise to break up incoming air at the hive entrance. Bees cluster in the 3/8″ spaces thus controlling air movement up through the cluster resulting in a larger cluster going into winter and a warmer colony in the spring – if the bee colony is large enough.

The slats are no longer placed crosswise. Plus, you are asserting that cold air going through the cluster is better than cold air going around it? Are you sure?

Third, the space below the crosswise slats is not dead air. Any space wider than 1/4″ allows for air movement or tirbulance (sic) as you refer to it. That is why thermo pane windows are spaced the way they are.

First, as I illustrated above, the slats are no longer crosswise, they are longwise. Yes, you can still buy plans for the other type, if that’s what you prefer. Again I quote, BetterBee: “Our slatted rack can be used in combination with our Varroa screens. The slats run from back to front so that they are directly under the hive body frames. That way when the Varroa mites fall naturally off the bees, they fall through the slats and through the Varroa screen.”

Regarding dead air space, let me quote Ruhl Bee Supply, “Installed between the bottom board and the bottom brood chamber, [the slatted rack] creates dead air space at the bottom of the brood chamber, keeping the bottom of the hive more protected, and encourages the queen to lay lower in the comb.” Or maybe you prefer, “The extra space produced by the slatted rack is said to keep a beehive warmer in the winter and cooler in the summer by creating dead air space.”

By the way, double or triple paned windows are designed to reduce heat transfer and prevent condensation. The space between the panes is great enough to reduce conductive heat loss and small enough to prevent convective currents. In any case, these windows are closed systems and in no way compare to slatted racks which are open to the outside air and populated with bees.

Fourth, USDA research says that non-reproductive mites are the ones that fall to the hive bottom board and through a screen bottom board. Hence the board becomes unnecessary to colony survival from Varroa.

It’s impossible to tell if your second sentence refers to the hive bottom board or the screened bottom board. But no matter—nowhere in my post do I say or imply that either one is “necessary to colony survival.” In fact, I’ve often said that I don’t believe screened bottom boards are are as helpful as we once hoped. In any case, I don’t see where I’ve said anything inaccurate. Again the subject here is how to use a slatted rack should you decide to do so—not whether screened bottom boards are helpful in varroa control.

Fifth, the rack allows the bees to control air movement, and swarm queen cells can be found on the bottom bars of the bottom brood nest because it is warmer above the rack. This results in larger colonies and faster buildup in the spring provided the queens and colony size is optimal for other reasons.

In my post I say, “Because a slatted rack moves the bottom of the brood chamber further from the entrance, the queen tends to lay eggs all the way to the bottom of the frames, thus extending the brood pattern.” This comports with your assertion that queen cells may be found lower in the hive. I do not speculate on whether this results in larger colonies and faster build-up because I simply do not have any proof of that. But I’m still looking for the alleged inaccuracy. Where is it?

I thought you should know these issues.

And here’s an issue for you to consider: Here at Honey Bee Suite, I do not make things up . . . I look things up. I have made mistakes in interpretation in the past, so when a comment like yours comes in, I spend a lot of time re-researching so that if I have made an error I can correct it. If I don’t know or understand an issue I will say so. I probably type the phrase “I don’t know” more than any other. Your kind of shotgun approach—the everything-you-say-here-is-wrong approach—wastes a lot of time and doesn’t yield any benefit. I stand by my original post.


Hive five: equipment to improve summer ventilation

Summer is coming to a close even though it was nearly a “non-summer” here on the Pacific Northwest coast. The corn hasn’t tasseled; the peaches look like walnuts. Nevertheless, my bees are healthy and I had a good honey harvest–much better than expected. My honey was capped and my hives are dry inside. What more could I ask for?

This is just a quick review of ventilation equipment I used this year. Although there are others, these are my favorite five.

Screened bottom board: In my opinion, this is a must-have piece of equipment. Whether or not it effectively controls mites is anybody’s guess, but it is great for ventilation. It allows large volumes of air to enter the hive while keeping out mice, large insects, wasps, and other bees.

Screened inner cover: In order for air to move through the hive, it needs a place to go. The screened inner cover is my favorite choice for reasons similar to the the screened bottom board. It allows plenty of air movement but blocks entry to predators. Before I began using them, the tops of my section boxes frequently became stained with mildew because moisture got trapped beneath the inner cover. Now that problem is completely gone.

Ventilation eke: I used ventilation ekes on a few hives where I was short of screened inner covers. These worked almost as well and would have worked even better with more holes. The ones I used had four holes, two on each of the long sides. In the future I will add at least one hole–and maybe two–on each of the short sides as well. The ventilation eke is an economical solution because I can staple canvas to the bottom and use them as moisture quilts in the winter.

Slatted rack: The slatted rack improves ventilation because it gives the bees a place to congregate inside the hive. This allows better air flow through the hive because the bees are not filling up the bee space between the frames. On hot days the bees hang in beards from the slats instead of jamming up the front entrance. It is especially effective when used with a screened bottom board.

Follower boards: Like the slatted rack, follower boards give the bees a place to congregate inside the hive. Unlike the slatted rack, the follower boards are at the sides of the hive. In my hives with follower boards, the bees used more vertical space for the brood nest. (Since the bees have only eight instead of ten combs per box, they expand into an upper box sooner.) This tall and slender hive structure is more tree-shaped and seems to provide a “chimney effect” that pulls the air through the hive. My hives with follower boards did especially well with honey production.

My next experiment will center on a gabled roof with ventilation ports at each end. I’m going to start with a prototype from a reader in Maryland who has had excellent success with his design. I will be using it for both summer and winter moisture management and writing about the results. Stay tuned for more about the ventilated gabled roof.


Why do bees collect on the bottom board?

Bee Brief bee

Brood nest temperatures remain fairly constant throughout the year at 93°-96° F (34-35° C.) But while a colony in late winter may consist of only 10,000 bees, a summer colony averages about 50,000 bees—and in some cases the summer population may reach 70,000+. With all those bees in the hive, the brood nest has to be cooled to keep it at the ideal bee-rearing temperature.

As temperatures increase in spring and early summer, it is not unusual to see throngs of bees sitting on the bottom board near the entrance to the hive. Even early in the morning after a cold night, they may be all lined up, looking like they are about to swarm.

However, congregating at the entrance is normal behavior for this time of year. Think of it this way:

Even a small cluster in the dead of winter manages to keep the brood nest warm. Individual bees take turns pressing their bodies against the brood and, by doing so, the baby bees are incubated at a cozy ninety-some degrees Fahrenheit.

But as the outside temperature gets warmer, so does the inside temperature. In addition, the number of hive occupants rises dramatically. So, instead of having a heating problem, the hive now has a cooling problem. Too many bee bodies sitting on the brood may make the brood too hot for optimum development.

In addition, the vast number of bees in the colony restricts the air flow through the hive. This occurs at the same time that the bees are trying to dry down the nectar and turn it into honey.

In response to these problems, the bees congregate in different places. They begin by sitting on the bottom board. As temperatures rise even more, the bees may “beard” on the outside walls of the hive, or hang in festoons from the landing board. Think of sitting on the front porch to stay cool on a hot summer’s day—same thing.

Follower boards and slatted racks can both provide additional congregation areas—places where the bees can sit without overheating the brood or restricting air flow through the hive. You can also help by providing screened bottom boards, screened inner covers, and upper entrances—all of which increase air flow through the hive.

I am probably guilty of over anthropomorphizing bees, but it is one of the easiest ways to figure out what they are doing and why. We need to stay warm in winter, and so do they. We need to stay cool in summer, and so do they. When we have excess moisture in our homes, we try to remove it—and so do they.

Remember, though, that even if the air feels chilly to you, the bees have huge numbers of individuals in their homes that we don’t have. So even a modest increase in the outside temperature can have a significant impact on the inside temperature, and the bees react accordingly.


An update on “How I overwintered ten out of ten”

Since I published “How I overwintered ten out of ten” several people have asked me what I did with the slatted racks during the winter. Since I always leave slatted racks in place, I didn’t think of them as an overwintering strategy, so I left them off my list.

Now I see that my way of thinking about slatted racks–as a permanent part of the hive–was confusing to people. So I have now added another bullet to my list and it looks like this:

• The slatted racks remained in place in the Langstroth hives all winter long.

Comment: I consider slatted racks basic equipment in Langstroth-style hives, so I never remove them in any season. In summer they provide a place to hang out during hot muggy days, and the queen tends to lay eggs further down on the brood frames–apparently because this area is no longer near the “front door.”

In a traditional winter hive with the Varroa drawer in place, the slatted rack adds an insulating layer of air between the brood nest and the Varroa drawer. This will not exist in the same way with the Varroa drawers pulled out. However, during cold snaps–or other times when the Varroa drawers are in place–the slatted racks again provide a “dead air” space that helps to keep the bees a few degrees warmer.

Thank you to those who mentioned the omission. I appreciate your input.