Looks like the key cover is slightly over sized and just needed reducing in size when it was built. And the part above it is slightly undersized. It’s easy to do but then other parts need to be detached and reattached to correctly fit. I think the filler as Dawn said or a fillet of wood.
It is however the part size and construction that is not correct.
You don’t need to treat cedar, but it does last slightly better if you do. If you had pine, I would be much more concerned, as the wood is not nearly as resilient. You haven’t done anything wrong - it is fine untreated.
it is hard to understand exactly what you are describing with the broken frames. If you mean some combs have broken and slumped down into the hive- it will be nearly impossible for the bees to repair them in a way that is useful for you the beekeeper. They will continue using parts of the broken comb- attaching them to other combs- and building in any gaps that are left. the end result will be comb all over the place and frames that cannot be pulled out like books in a shelf. You really need all your combs to be like books neatly arranged side by side. It sounds like you might need some help from an experienced beekeeper to go through the hive removing the damaged comb and replacing it.
I actually recommend that novice beekeepers use frames with wire and foundation- especially in brood boxes when they are first being established. Foundationless combs can be great but they can also cause issues if they are not built out correctly and evenly. Using foundation can really help in easily and quickly establishing a very manageable brood box with even frames with a high percentage of worker sized cells.The initial expense of wax foundation soon pays for itself in the form of a perfect brood box that is easy to manage.
Jack- thank you this is advice is extremely helpful. I’m going to get one frame with wire and foundation but I have to order for it to be delivered. They say they can’t guarantee it won’t crack bc it’s brittle. If it cracks, will the bees manage? Will it counter act the benefit of getting a frame with foundation?
Thanks for you expert help!
I am thinking there is a bit of confusion about what is advising and the way you are reading it. What Jack is explaining is to use a frame that is wired and has foundation already in place in the frame fitted into the top bar slot and melted to the wire. Maybe your thinking of buying a sheet of foundation separately to the wired frame, and that is brittle and flexible as it is not supported and protected by the frame.
I understand that as you have one hive you don’t have the gear to make up and wire frames so that is where a local bee keeper can help you out who is happy to sell you a made up brood frame already wired and with the foundation already in place… I wouldn’t expect that to arrive thru the post or a courier without being damaged.
Cheers
If you buy foundation, you are going to have to discard the comb which fell out. Are you sure that you want to do that?
If it cracks, the bees will manage, as long is it is still aligned with the frame. If it isn’t, they may get creative, and then you could have the same problem that you already have.
Why not rubber band the piece that fell out back into your existing frame? It isn’t that hard to do. 
The whole story:
3 weeks ago I was in the brood box doing a check. I took the frame on the side out and leaned it up against the front of the hive (something I learned in some video/from a beekeeper/somewhere in my self taught beekeeping) so I could easily pull the rest of the frames out. However where ever I learned this from perhaps doesn’t use frames without foundation. The comb that the bees built was heavy and it slowly broke off as I was looking at the other frames. Because my frames (from flow hive) are foundation-less, it was very heavy full of honey and brood, and the bees had not completed the entire comb (it was not attached to the bottom of wooden frame) is why it broke. It was devastating and I’m a beginner and it made me cry. But alas that’s what happened. My question is:
I see the bees have not rebuilt this frame. What would you experienced beekeepers do at this point? I just took of the honey super.
Thank you for your help. I know it was a poor mistake
What did you do with the comb? Is it still in the frame, or did you throw it out?
If it is still in the comb, make sure it is straight, with rubber bands if necessary to hold it in line with the frame.
If you threw it out, just leave the frame in the hive. No need to buy a new frame or foundation, etc. They probably will not rebuild until there is another nectar flow - in your climate, that will likely be around April next year. Even if you give them foundation, they likely won’t use it until Spring.
@JoannaD What Dawn has said is very true. If the comb in the frame is repairable the bees will do it but not use the cells along a fracture for brood but will use the rest of the frame. Using rubber bands to hold everything together till the bees can repair it more permanently is a good move.
As with a lot of bee keeping there is more than one way to get to the same end result, When I am making up a new hive I wire my frames and fit bees wax foundation and it works well for me. with two possible issues, don’t buy foundation that might be of Chinese origin as they are buggers for blending bees wax with paraffin wax for more profit as paraffin is much cheaper. The other issue is that even locally produced foundation may contain some toxins, and there is no way to know if it is present. Over here I only buy from the one producer of foundation who is in a big-way and so far his wax is good.
Cheers
Hello there Joana,
don’t worry to much- mistakes happen. Yes: when you have a foundationless frame you have to be very careful how you hold it- It needs to be kept in a vertical orientation as it is very delicate and will break easily if gravity can pull it to either side. As you found. Once it has been attached at the sides and the bottom it become much stronger- after a year of use in a brood box it will be very strong once bee cocoons have strengthened the wax.
So- it sounds to me like you just have a gap where it was - and the easiest solution would be to slip in a new frame of foundation with wires. You could also put in a plastic frame coated with wax in a pinch (I prefer natural but plastic does work too).
You could salvage the comb as dawn has suggested by rubber banding it into an empty wooden frame: however it takes a little skill and maybe reading to work out how to do this well- and it depends ont he state of the piece/s of comb if it is worth it or not.
To see how rubber banding should be done- the video linked int he article below shows the best method I have ever seen- the trick is the rubber bands he uses to push the comb pieces up to the top bar of the frame. I have copied this method with brilliant results. After the bees repair an re-attach the comb they chew the bands off and throw them out the front door of the hive:
I kept the comb - out of interest to show my kids. But it’s full of dead bees and is that sanitary? I had left it in front of the hive for a couple days after it broke so the bees could take from it what they wanted.
I think I wont use an elastic to put it back. It looks old and gross now, having sat outside and now is 3 weeks old.
I may purchase a wooden frame with foundation. with wires. They can use it in early spring.
Thank you!
Bees love gross wax. Seriously! They will clean it up in no time. Just rubber band it in the right way up, so that the cells slant slightly down towards the center of the comb. If you put it in upside down, the bees can’t fix it.
What I would do in your situation is to find a local bee group or a helpful bee keeper and buy a wired frame with foundation fitted and put it into the outer position of the brood box today.
The brood cluster won’t be disturbed and they will build out the comb when it suits them to first be used for stores but then the inner half of the frame is available for the queen to lay in come Spring.
As you haven’t said, but I assume, the brood box has a gap left from the missing frame and that is not good for the colony. They will build wonky comb which will only make a bad situation worse.
Cheers
@JoannaD don’t be too hard on yourself As with all new ideas and new efforts, unforeseen problems happen! The same comb collapse happened to me too, and it killed my queen 
which I didn’t know until I found an open queen cell later on!
Dawn and Peter gave you all the important points you need to go forth from here, but I’m replying to add a bit of context that I hope will help. When Flow went about putting together their amazing kit, they weren’t only focused on the harvesting of honey - they wanted to provide a whole package with equipment and information to support beginner beekeepers in the best way possible, for an international audience. A lot of newer ideas about how to control varroa mites were being discussed, after data from a couple decades of widespread miticide use showed bad effects on bees. Many well-known beeks promoted using foundationless frames, so bees would build cells to their natural size, as an important component of non-toxic mite-management. So, the Flow brood boxes all came with foundationless frames, and they released a nice set of instructional videos to point out details like how to lift and manipulate these frames, and also how to fit them with foundation instead.
When you’re a beginner, some of that info gets lost and it’s hard to appreciate the inevitabilities of physics until you witness them in action 
You can keep letting the bees build natural-sized cells, but it’s clear that the large vertical space of deep frames needs to be supported in some way - so if you opt for foundation, you can choose ‘small cell’ kind. Or, you can modify your frames with more structure like I did, by affixing 3 bamboo skewers inside the frame, spaced across vertically.
Good luck & let us know how things go! 
This is very informative thank you Eva
Hi Dawn- I did the rubber banding- how does this look to you? the bees started to build a bit of foundation in place of the broken comb. I had to break the broken piece a little to fit it into the space in the frame. It seems like it’s going to be so wonky! But boy do I love an experiment like this.
Thanks for your encouragement!
Joanna
Jack- Do you think this rubber banding is any good or should I take it out?
Well done, your banding looks great! Very proud of you for trying so hard.
Hi Joanne…back to your original post…it’s unfortunate that this damage occurred at this time of year…i.e. after the honeyflow and just before winter. Your bees will not repair the damaged frame now unless you do some supplementary feeding (sugar syrup)…or you could save a full frame from your or another beekeeper’s hive and place it in the space. Your idea of an in hive feeder also has merit as I know some commercial beekeepers in my area (Alberta) winter their colonies with feeders in place. Just make sure the brood area is intact (frames moved together) and you should be adding feed if your single brood box doesn’t weigh 50-80 lbs…this is usually done in the month of September as bee dormancy hasn’t set in yet.
May I also recommend that you consider changing over to either plastic foundation or totally molded plastic frames…although politically incorrect, the plastic foundation/frames give you structural integrity that you can rely on that may come in useful down the road.
I am continually rotating brood frames into honey supers and vice-versa and I know I could be courting disaster by using wax foundation frames (especially un-wired) in my extractors…this happens much less frequently with plastic foundation/frames.
Plastic frames also give you the option of reconditioning…so at a certain point in their life you can just scrape the frame content right down to the plastic foundation without damaging the frame…the bees love this and rebuild it with relish.
Often the contents of the frame contain beebread which is an excellent natural supplement and I feed that back to the bees in the fall and spring…in the photo you can see that I left a strip of original brood cells down the center for comparison’s sake.Living in Canada, you may or may not have issues with bears. The photo shows what happens this time of year. I saw the bear and it was huge…walked right by my extracting room when I was working. I had left a stack of empty honey supers outside overnight but they were very close to a running generator so I thought the bear would stay away…wrong! The solid molded plastic frames had been worked over by the bear but absolutely no damage to the frame other than comb being crushed. In my mind this was the ultimate test.
For a biological control of varroa, I use one drone foundation bait comb (you can purchase plastic foundation that is drone cell size which varroa prefer or build your own) on the outside position of my brood box.
I hope this may help…and good luck with getting that hive through winter.
Doug
Fantastic post, Doug. Thank you so much for weighing in.
