A DIY Formula to Create the Purrfect Multi-Cat Cardboard Box Condos

Things have been a little hectic over at the Xavier household with the new addition to the family – Bjorn, a stray from our neighbourhood who just wouldn’t leave our property to the point where we eventually took him in.

The little fella’s come with his own set of problems, from vomiting issues to ridiculously dreadlocked hair (and a few pretty darn tangled mats left over after the vet shaved him). He’s been adjusting ridiculously well to life indoors, and most of the issues have resolved themselves, or at least made significant headway. The one thing I really still want is for Avery, our previously only-child cat, to be a lot more comfortable with Bjorn’s presence in the house.

The two have certainly made a lot of headway in terms of the squabbles between them dying down, but when Avery’s particularly moody – say, right before he gets fed – he often takes out his agitation on Bjorn, leading me to sometimes separate them. I keep them completely separate by placing Bjorn in his fully decked out room whenever we leave the house for prolonged periods of time, but luckily Thomas and I work from home, so they get plenty of monitored interaction time, which again, I definitely think has helped them make progress toward accepting one another.

I’ll go over all the things I’ve done to try to foster some positive energy between the two (one of which includes decking out a cat room for the two to spend time together in), but one main thing I found has helped is to place a lot of hiding places for kitties in the spots their fights tend to frequent. I feel like having enough of these mini-territories for each cat to spread out and stake claim to are great, but they don’t prevent fights altogether by any means, which is why I’ve also found it important to have “escape routes” with any cat house/condo I’ve created for these two cats with cardboard. This means two doors – at least – in every single cardboard house.

I’ve got a bunch of these spread in the areas of the house the cats frequent and am planning to make a slew more as they get thrown up in by Bjorn (infrequently now, but still may) or peed in (sadly happened in my favourite cat condo for the two, since Bjorn associates cardboard boxes with litter boxes a little and will at times pee in one – again – really infrequently).

Here’s a sample of Avery sitting in one of my cat condos for the two fellas, this one upstairs in the hallway –

My formula for creating multi-cat condos for cats that sometimes squabble is as follows:

1. Cut out your first door. This door can go on any side of the box, though if the side of the box is large enough to fit a door + plenty of extra “blank” space, the door should be positioned off to the side (left or right), rather than the middle. The door itself needs to be big enough for the cat, plus considerable wiggle room.
2. Once you’ve got door #1 cut out:
   If you positioned your first door on the left, shift your box once to the right and cut out another door on this side; position the second door on the right of this side.
   If you positioned the first door on the right, shift your box once to the left and cut out another door on this side of the box; position the second door on the left of this side.
3. Add a “window” in the blank space next to each of the cat doors, making these varied sizes, shapes, and at different heights.

Yes, I’m so sorry if this was confusing – it was hard to explain (I tried!), and if you can make heads or tails of my instructions – that’s it!

(Also, pleaseohplease if you have a better way of describing what I’m trying to say, leave me a summary in the comments; would love to make sure these instructions aren’t clear as mud!).

The way I have the doors makes a sort of L shaped runway for the cats to go through, and they naturally do flow in one door and out the other, which is amazing to watch. Both cats have often quite literally run in and out, through the box, rather than taking time to sit inside their cardboard cat condos. I feel this proves the pathway creates a pretty natural flow for them to follow, and in my head, I get the sense this may help lessen the likelihood of a cat feeling “stuck” or trapped if another comes in to pick a fight and the first needs to flee.

Now for some pictures. Here’s my favourite of the two multi-cat cardboard box houses I had in the downstairs hallway –

Too bad it died a death-by-cat-urine, but it will live on in my memory nonetheless. Loved this one, and Avery and Bjorn both used it a considerable amount before it suffered Bjorn’s fatal blow.

Here’s the second of the two placed downstairs; so far still living:

This one is meant exclusively for Bjorn, who is about half the size of Avery. Didn’t make the doors big enough for Avery to be comfortable getting into, hoping Bjorn would take more of a liking to it and stick to using it, so Avery could have the larger more often to himself. Seems to have worked (pre-large condo fatality).

As you can see, it really doesn’t matter what size cardboard box you use, or even which side you have up. So long as the box can fit the cat, you can make it work, and honestly, I find the odder the shape, the more adorable the end result.

I personally don’t tape up the bottom of the cardboard boxes at all, just fold the box down three flaps on top of each other, then tuck under the last flap the same way you would were you to close a packing box without tape. I then test to see if the side I want “up” can hold itself. Sometimes the inside of the box falls because it’s not taped up nicely inside, and if that happens, I choose the “fallen” side as the base of the condo.

You can do things up however you want, changing up shapes and sizes, and you can add plenty more doors or windows as you please. I’ve just found this to be a good general formula for creating multi-cat cardboard boxes my kitties love, and so I’ll continue to use it as a baseline for the future cat condos I’ll be making for my furries.

Any tricks you’ve learned about making great cardboard cat houses for multiple cats?