How to use a slatted rack

The slatted rack is my all-time favorite piece of bee furniture, and I wouldn’t try to keep bees in a Langstroth-style hive without one. I insert one whenever I build a new hive and leave it there year-round. If you’re not familiar with them, a slatted rack (sometimes called a brood rack) fits just beneath the lowest hive body and above the Varroa screen or bottom board. It has the same outside dimensions as the brood box and is about 2 inches deep.

Slatted racks provide dead air space below the brood chamber. This layer of air helps to keep the bees cooler in summer and warmer in winter. In the summer when populations are high, bees congregate in this area which reduces congestion in the hive, spreads out the heat load, and facilitates ventilation by fanning. This increase of space and lessening of heat seems to decrease swarming as well. In the winter, when the entrances are reduced, the air space within the slatted rack acts as an insulating layer between the brood chamber and the cold area below the hive. It also removes the brood nest further from the drafty entrance.

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.

Here are some caveats about using slatted racks:

  • If you use a screened bottom board, the slats need to run from front to back— the same direction as the frames. The idea here is that the mites will fall between the slats and then through the screen. If you have the type of rack that runs crosswise, fewer mites are going to fall through so your Varroa screen will be less effective. Similarly, the number of slats should match the number of frames. If you use only nine brood frames in a ten-frame box, your slatted rack should have nine slats. Some manufacturers have designed racks that can be modified for this configuration. There are also slatted racks made specifically for 8-frame equipment.
  • At one end of the slats (running perpendicular to them) is a flat board about four inches wide. This goes at the front of the hive and is said to reduce air turbulence at the entrance.
  • But the most important thing to remember about slatted racks is this: they have two sides, a deep side and a shallow side. The shallow side goes up. Repeat. The shallow side goes up. If you put it in upside down, the bees will draw comb into the empty space. The next time you try to reverse brood boxes, you’ll first have to cut away the comb and brood hanging off the bottom. You can’t even set the box down without doing serious damage. This is not fun, especially when the box weighs 90 pounds and the temperature is 90 degrees. (Hmm . . . Do you hear experience speaking here?)

However, once you get your slatted racks successfully installed, you’ll be a convert. Whatever the reason, hives with racks seem to do better than hives without.




BRAVO! Thanks for the informative description of proper(most effective) use of slatted racks. I find too many beekeepers are lacking the understanding of many hive components and their proper use for maximum production/hive health.


I have been wondering what those funny-looking slatted things were for.


Anywhere a design for building one?
Second question, can my gravatar appear with my Comments, instead of the cartoon critter? How I do that? Thanks!



There’s a design for building one here:, but the slats should go longwise, not shortwise.

My software accepts gravatars and automatically posts them if they are attached to your identity. How you do that on your end, I don’t know. Go to the gravatar site and see if it explains.


I tried five this year (summer 2012) and was impressed with the number of bees clustering on the rack and not in the brood area congesting the queen. I plan to use a rack on all colonies next season. I’m really, really impressed with the slatted rack used with a jumbo hive.



Like I said, I wouldn’t keep bees without them.

James C Bach

Hi Rusty. 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.
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.
Third, the space below the crosswise slats is not dead air. Any space wider than 1/4″ allows for air movement or tirbulance as you refer to it. That is why thermo pane windows are spaced the way they are.
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.
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.
I thought you should know these issues.



Thank you for posting about the article in the 1970 Gleenings in Bee Culture about the Bovard Rack. I am interested in and respect your opinion on Bovard rack/slatted rack because you have used them and have experience and knowledge about bees. I have been associated with bees for about 40 years. Inspected 100s of thousands of bees in almonds and have literally thought I had seen it all. Only to discover that I see many new things every year.

Needless to say most every beekeeper thinks he has all the answers. I’ve seen beekeepers with 1000s of hives average less than 8 frames of bees and those that consistently might average 15 or more frames of bees. My goal is to keep my 6 hives alive and prospering without the use of any chemicals. They have been without chemicals and no treatments for 9 years. I feel that with the right bees, and with the right equipment designed for the bees and not ease of the beekeeper, we could find some real helpful solutions. I feel you are headed in the right direction. As we will never know unless we try the theories.

I appreciate and thank you for your experience and research and use of the things I have read. You may have already addressed this, but the old saying of cold doesn’t kill bees moisture does. Proper ventilation in a hive I believe is a big part of survival especially in colder climates. If we can wipe out moisture in the hive and proper or good ventilation with our knowledge of bees that we have, I feel we will be well on our way to successful beekeeping and having happy healthy bees. Everyone’s comments can be food for thought but the tried and tested ones through use can be relied on much more. Thanks Again Ron


Hi, the racks idea sounds well. The thing about the heating the hive during the winter or cooling them during the summer is that you can achieve that by rotating your hive by 90 degrees. Also varroa drops from bees, because bees fight it, bees are able to take it off their backs (there is a video of it; will post it if you really need it…) So when varroa drops from the bee it stays ON the slatted rack and then it climbs back on another poor bee (in 50% cases). You may wish to reconsider using them. Keep up the good work with the rest of stuff :)


“The thing about the heating the hive during the winter or cooling them during the summer is that you can achieve that by rotating your hive by 90 degrees.”
Please explain this to me as it makes no immediate sense.
Also, if the slats for the rack are directly underneath the frames, how would the mites land on them? Again I am confused. Can you clarify your statements?



For what it’s worth, I don’t understand either.


As long as it isn’t just me.

Lindy van der Meulen

Hello Rusty,

I am trying to visualise a slatted rack from what is written and I asked by supplier of hive materials in Belgium and NL but no-one seems to have them here. Can you supply a picture and do you think they come in 11 slats. My hives have 11 frames. Thank you



Odd that I don’t have a picture. I’ll have to fix that. But if you Google “photo of slatted rack”, hundreds of them show up.

Lindy van der Meulen

Hello Rusty,

I found enough examples today but all on American or Canadian sites. I have access to bee stuff suppliers in The Netherlands, Germany, Belgium and England not one of them has this item in their stock. I e-mailed the three you had mentioned in the original post but they do not send to Europe or if they do the minimum order has to be for 250 dollars.

Are there any other European readers to Rusty’s site who can help me further to get some of these. If not I am going to have to find someone to make them for me.

Thanks for now,


Does anyone know a supplier of slatted racks in Europe? Does anyone have a plan for making them? Please let us know.


After reading your endorsement of slatted racks, I bought some. This will be my third year of beekeeping and I plan to have 8 hives this summer. I must have been thinking about notes about moisture inside hives that winter over–I painted the racks completely. Now I am thinking that was wrong [I should have read the assembly instructions more carefully]. Can I use these painted slatted racks? Maybe if I leave them out in my garage for the next two months so the paint smell wears off? Thanks. –Kevin



They will be fine. Just do as you say, and let them air out before you put them on the hives. Most of the volatile components will off-gas in the first few weeks. Don’t worry; it’s not a serious mistake.


Thanks, Rusty!


Hello Rusty and other readers,

I looked on your blog for a subject to do with hive furniture for the question I want to ask you and I thought this about slatted racks came close enough. By the way, I have my first slatted rack now, a friend made it for me; it is not yet in place though.

Last night 13 March 2013, I started my BioDynamic bee course. We have had a few readings from the man who is our tutor so I already do value what he has to say. In last night’s lectures he mentioned that in the past, when screened bottom boards where not used, the bees where very particular about their housekeeping and wax mull, bits of bee bodies, unwelcome visitors anything they didn’t like; all these where removed very quickly.

Nowadays the bees can’t get to this ‘their household rubbish’ so we the bee carers/keepers/guardians whatever have to make sure that the screen and what ever you have under it is cleaned. It is something else we have taken away from them and so we have changed their sense of being….. Perhaps also their sense of well-being. Also we don’t do the cleaning job as efficiently or as quickly as they did. What do you think of this Rusty? Do you use screened bottom boards or solid ones? I thought he had a valid point.

He also talked about moving the frames about inside a hive or moving them to another hive was like taking away some of our ribs and putting someone else’s ribs in their place….. In BD the tone is that the whole colony is one complete body not so many thousands of individuals. So if you move racks 2 and 9 it is vitally disruptive. Any thoughts anyone. I felt very much that it was logical what he said.



I really don’t know what he’s talking about. I use screened bottom boards with my hives that are on hive stands. There is nothing but empty space underneath. When things fall from the combs, the small particles fall through the screen and down about 18 inches to the ground where the debris is decomposed in the normal manner–by soil organisms and other insects. Things that don’t fall through the screen are removed by the bees just as if it were a solid bottom board. If anything, I think it is easier for the bees to keep it spotless. I’ve never had to clean the screen of a hive unless the colony died. Live colonies keep them immaculate. Having nothing under it is the key. Has your tutor ever used one?

Most scientists believe that a bee colony is a superorganism, basically as you describe. One organism is made of thousands of bees. But I think the analogy of ribs is wrong. Frames are more like furniture. If I come in your home and rearrange your furniture, you will recover in no time. Bees recover when you move their frames, especially when you take care not to disturb the broodnest. Furthermore, when bees swarm or abscond, they deliberately leave their home and furniture. If new frames were like new ribs, the bees would never swarm or abscond. By the way, when humans move, they also leave their home and maybe their furniture, but they don’t leave their ribs. Not a good analogy, and not valid.


Anywhere I can get a slatted rack if I’m running 11 frames in my brood chamber?




Brushy Mountain used to have a slatted rack that you assembled yourself, and you could put in either 9 or 10 slats. I don’t know if they still have it, but it would be easy to add an extra slat if you wanted. Looking at mine, it appears there is plenty of room for 11. You might contact them and ask.

Laura Colburn

I added slatted racks to my two hives this spring after reading your article. My bees are staying much cooler this summer. We had our first 100+ degree day last week, but they stayed cool as cucumbers. They’re not crowded around the entrance either since they have lots of space to gather under the frames. Thanks for posting the information about them!



I’m glad they are working for you. I’m a believer.


Hi Rusty,
Was wondering if you’ve heard any difference in the results of the slatted racks which line up with the frames in order for the mites to more easily fall through verse the older style which run perpendicular to the frames.
I would think the old style racks which are perpendicular to the frames would provide better draft control and I also wonder if the new style really allows for any better mite drop…



I’ve never seen any studies on which type is better for mite control, although the design was changed in order to facilitate mite control and the new design seems to make more sense. If a mite lands on the crossbars and then a bee walks on the crossbars, then the mite can jump on for a ride. If the bars are lined up with the frames, the mite is more likely to fall down further and straight through the screened bottom.

I am sure that the old perpendicular style would impede air flow, which is another reason I wouldn’t use them. Most times of the year I want good, uninhibited air flow. A good draft helps to dry honey, helps to keep the brood nest from overheating, and in the winter, helps to remove condensation. If I wanted to reduce the airflow in cold environments, I would do that by closing off the screened bottom, shrinking the entrance, or decreasing top ventilation. I wouldn’t touch the slatted rack.


This is a great information. I love your page. This is my first full year of beekeeping. I got into beekeeping last year in Aug. I wintered two hives that are doing well.

I also build my own hives. After much research I started building my own slatted bottom boards. I do mine a little differently then the store bought ones. I make them about 3 in. deep. It will have the same effect as the store bought ones, but it also gives the girls more room to hang out on rainy days. More room in the bottom to me would mean hive isn’t as crowded.

I now have 4 hives, one split and a package. All have slatted bottom boards. I love them! Hope you have a great day!



Deeper is probably better. It amazes me how they like to hang out on the slats on those hot, hot days and nights.


Hi All,

Any thoughts on how best to go about adding slatted racks to a set of hives laden with heavy frames of honey? I can tell from reading the above I basically need to separate the lower deep from the bottom board in order to do this (I run 2-deeps with medium supers above). So I guess I’m really asking for tips on how to “under super” the slatted rack. I’m not sure I can lift the top deep off the lower without pulling at least some of the frames. I have a spare deep that I can use as a frame stand while manipulating the boxes. Learned about running all mediums too late for this pair of hives…. :)



I think you answered your own question. If the box is too full to lift, pull out some frames. That’s how I do it.


Is the slatted rack something that would be beneficial on a warre hive? I’m just starting out and I’m curious since it only seems to be used on Langstroth-style hive.

I contacted a warre hive guy asking about it and he’d never seen a slatted rack. When I showed him the rack with its dimensions (from the internet), he commented that the gaps were large enough to admit mice.




The slatted rack is not designed to eliminate mice. To do that you can use a screened bottom board and a mouse guard at the entrance in addition to the slatted rack.


Alright, but is it something that would benefit a warre hive?



They say so, on their website.


Hi Rusty, Thank you for the information bc I am on the process of building a Valhalla hive and it calls for a slatted rack. In a recent conversation with the designer and long-time beekeeper, Richard Nichols said that the bees can also use the slats to brush off mites. The mites fall through the inserted screen and land on a mite board. The 3/4 x 19 1/8 slats require 3/8 bee space.


I’m trying to put my first hive together, kind of like puzzle pieces. This article just inserted my first piece. Thanks!

David Manning

Rusty, I have some images of the slatted racks that I built for my hives. They show the top view, bottom view and positioned on the hive properly.


Janice Andrews

Will have my bees next weekend. Have been reading your articles and the comments about slatted racks, and think I’d better get some. Today someone posted on Bees and Beeks about Beetle Baffles, and I’m wondering if they would/could be used in addition to the slatted racks? or if that’s overkill?
BTW, I took TWO beginner beekeeping classes this winter and neither mentioned the racks! I wonder why???



I think they could work together. I would just put the slatted rack directly above the Beetle Baffle. It’s probably not overkill, especially if you have beetles.

Most beekeepers don’t use slatted racks, but many who do see improved performance. I think they are not mentioned because beginner kits do not include them. Since it is an optional item, its inclusion would increase the cost and perhaps dissuade people from their first purchase. Commercial keepers don’t use them either because they want to keep costs low and maximize trucking efficiency. It is mostly hobby beekeepers who pamper their bees (guilty) that use some of the specialty equipment.

Janice Andrews

Thanks, Rusty. I’m sure you’re right about why the slatted racks aren’t included in starter packages. But they gave us so much info about feeding, treating, etc, I would have thought they’d at least mention them!
No beetles yet, because no bees, but I think I’ll get a couple of the racks to give them the best chance.


I can see how the mites would fall between the spaces in the slatted rack down through the SBB, but don’t some mites just accumulate on that flat board on the slatted rack that is positioned towards the front of the hive?


Most likely. Everything in beekeeping is give and take, do the best you can.


I just got my slatted rack from ValleyBeeSupply. Part of what left me scratching my head about the slatted rack is that it doesn’t seem to have that small flat board that goes near the front AND yet, the picture on the website seems to indicate the item has that flat board (the one that goes near the front). Is the latter a design error or is that a new design? Can I use it in my hive without that flat piece or not?
Thanks in advance! :)



I assume they changed the design. Many people don’t like the flat board in front because they say it reduces mite drop out of the hive. Just go ahead and use it.


Hi, after reading about the slatted board I have a question about the varroa mites that falls down and the higher number of bees that are walking around in the space under the slats, why don’t the mites fall on and stay on these bees?



They probably do. The slatted rack was designed before the introduction of varroa mites, and the slats used to go the other way, crosswise. Once varroa screens came into use, they changed slatted racks to run parallel with the frames, so mites could conceivably fall through. Like many people, I do not see much benefit in screened bottom boards for varroa control, so I don’t worry about the mites not being able to fall through. The real benefit of screened bottoms is better hive ventilation. Mites have to be controlled in some other way.


Hi Rusty, thanks for your answer. Having thought a little more about falling mites it occurred to me that having a couple of supers and a brood box or two the mites will have a hard time to hit the varroa screens. I think a top bar hive will allow the mites to have a free fall through the screen, perhaps that is a known fact?



You are right, the fewer obstructions between the frames, the more mites are likely to fall through.


I’m interested in using a bottom rack but was just going to staple a screen to the bottom of it and use the rack as my screen bottom board. I’ll be utilizing an upper entrance. my question is, I want to use a quilted box as well and leave it on all year adjusting the filler material as needed throughout the year. Is this too much ventilation for any season? Winter or summer?



Where I live, that would not be too much ventilation. In some places, it might be.