Use a Rubbermaid Tote that's about 8" high (can't remember the capacity), & use a utility knife to cut a squarish or wider piece out of one end to make the 'threshold' lower for your older cat.

Cut a similar doorway, only make it really huge so the cats can see inside & feel comfortable going in there, in the bottom of a really big Tote & set the other one inside & put the litter in the smaller box.

You can put the top on the larger box if you want & if the cats will go inside;
it'll keep the litter from being kicked all over the place.

When you go to the store for these boxes, put the smaller one inside the larger one to be sure it'll fit.

Be sure to clean your concrete floor like you have OCD.
Concrete is porous, & it's hard to get the urine or ammonia smell out of it.
Use bleach, & rinse it thoroughly before the cats walk on it.

We had the same problem and it was solved by purchasing a box with a larger usable area (cleaned daily/not high sided/no cover).

Same here. Larger box, not high sided, cleaned twice a day.

Turned out an under the bed storage box is big enough, easy to fit in my space, and has enough room the cats can move around and squat without hitting their tails on the wall. That seemed to be part of the deal. They're proud of their tails, and make quite the effort to keep them clean.

For those who mention larger box can you tell me how large yours is? I have two very jumbo boxes and I'm wondering just how large you are referring to and if it's larger than what I have.

I measured this years model for you. It's 34" X 16", with 10" clearance on the wall side and a min. of 12" on the three other sides. Slightly smaller than previous boxes but seems to be working okay. I'll probably go back to a tiny bit bigger next time. It almost looks cramped for my bigger boy. He has to make quite the point of facing north / south...the long direction ... then fails to cover sometimes. That didn't happen before. Sides are below tail height.

I got the idea from a gal that does rescue work with cats, through her vet. She has a room for them and a kiddie swimming pool for the litter. Beach front property baby. :D

You can use a plastic tote, as mentioned above, but get a really tall one, and just cut a circular or square opening in the side. Then you can just leave the top open.

There are a lot of diy litter boxes online using totes.

This worked for me. It didn't matter how large the box itself was because my elderly cat will invariably perch on the very edge, no matter the size. I clean the box twice a day, but I don't think she likes the feel of the litter on her feet to squat in the middle. So in lieu of fitting her with little kitty slippers, I finally kept the "normal" sized litter box I had, but I put it in the middle of an overturned cover from a large Rubbermaid storage bin.

The cover itself is not very deep so she had no objection to stepping over it. At least this way when she misses, it all stays in the cover which I take outside and spray off with the hose. Actually I have 2 of the covers so one is always clean to swap out in case I don't have the time or inclination to go outside and spray it off. I live in AZ so the weather is rarely prohibitive. Unless you consider 110 degrees prohibitive!

PhoneLady - I did something like that with a previous geriatric cat when I had to have a litterbox in another location. I found a great big tray that is supposed to go under a dog kennel. That idea worked but space constraints would limit where I could used something like that. Same issue with a kiddy pool if you can't turn a room into a cat bathroom.

I have this problem, too, because my 'big boy' likes to pee in the corner of the litter pan. I am at my wit's end...bought a huge rubbermaid pain, 2 feet x 3 feet, and he STILL backs his butt into the corner and hangs his tail over the edge of the pan, and sometimes pees with such a force it shoots a foot out (if he is facing in....shooting over the mat I put under the pan, out front, on the carpet)....I can't buy a covered pan because of this, but he was going under the desk, I guess he felt safe under there, so we ended up putting it under the desk because of that...I'm thinking I may have to buy some of those rubber cat mats and tape them up the sides of the desk and the wall , tucking it under the pan, with a matt under them, creating a rubberized cave to catch the pee, to keep from having the urine smell permeating our house, because unfortunately the room their litter pans are in has (now permanently ruined, but we are not financially in a place to replace it, so we are continually cleaning it) carpet in it. The one they pee in is surrounded by pee. Really wishing I had known when we moved in and replaced the linoleum and carpet in the kitchen/living area with hardwoods that we had spent a bit more and continued it into the front bedroom/den that our litter pans in, as our older cats soon passed away and we and the new kittens developed different habits....and had we known this would be one, we would have had an easier time of cleaning pee off hardwoods than out of carpet. Or at least, protecting the hardwoods from it.

Lisa,

Since your litter boxes are under a desk, it's possible your big boy is peeing over the top of the litter box because he's unable to position himself in a sitting position to pee. Imagine yourself trying to pee when you can't get into a squatting position.

I would move the litter box out from under the desk, block off access under the desk, then place the box where the cat feels secure. Maybe place some type of screen in front of the litter box. If you have more than one cat, and only one litter box, that's probably why he chooses to go under the desk. You need at least one box for each cat and don't place the boxes side by side. Place them in different areas of the house to prevent sneak attacks when one of them is using a litter box.

No, it is a tall, wide desk he was going under to pee in the corner anyway, so we put the large litter pan in there...I have been corrected by my husband, who uses that desk and has witnessed him using that pan since we switched to it (larger, 2 feet by 1 1/2 feet and 8 inches deep) and put it where he had taken to peeing (after properly cleaning the carpet, walls, desk, etc). He squats in the middle, but stays his pee with such force it spatters over the end, and as he is 15 + lbs and LOOOONNNNGGGG..... I may try turning it lengthwise so the long end sticks out, perhaps he will move more to the outside end when peeing, then maybe his spray (he IS fixed, BTW) will stay more contained.

So on talking it out, as I write this, perhaps you are right, I just wasn't thinking it all the way through...I will try re-orienting the box long way in and . Also had the thought of putting the inside end inside a sideways rubbermaid container to protect the wall and carpet, too....can just wash that off when cleaning the litter pan. :)

I like the idea of the adult pads and also the under the bed tote....Will be doing some shopping....

- Try placing a shower curtain under the litter box to catch the cats spraying over the side of the litter box. My senior cat can't stoop and therefore pees over the box sides. When he pees, I usually lay a papertowel or even experimented with a newspaper (which worked great) over the pee to wick it. Then when I scoop the box, I pick up the "wicked" paper.

I’ve had this problem with my cat even when she was a baby. Even when she was tiny, she always had to be on the edge of the litter box, she positions her bottom at the edge and sprays a foot or two behind her. I hate it!! I put down a “potty pad” for dogs Which helps with the constant scrubbing. But its a nightmare, six years of this and I don’t know how to fix it

I am having the such a problem with my male cat. He will not squat to pee just stands there, gets in the box and pees all over the walls, floor, etc. We have taking him to the vet nothing wrong plus he didn’t always do this and really nothing has changed in his life so just don’t know. We have changed litters, tried different box’s nothing. We just last night cut an entrance into a tall rubbermaid and just before our eyes he came and peed standing up which went over the top. I don’t know what to do we clean the boxes 2 times as day. The basement smells and i just don’t know how to break this habit. Such a nightmare!

I know you said youve tried all types of different boxes, but i finally fixed the problem with Getting a top entrance litter box. If that hasn’t worked for you, I used to use those puppy potty training pads and put them around where she would pee. It’s not the best solution but it was better than mopping 3 times a day

The only box I have found that they can spray all over inside and the urine does not come out is: Petphabet Covered Litter Box, Jumbo Hooded Cat Litter Box Holds Up to Two Small Cats Simultaneously,Extra Large. Amazon carries it. Has been working for years for two of my boys who could pee over the top of a Rubbermaid high sided container! Plus the only product I have found to actually REMOVE the smell of cat urine COMPLETELY is Charlie's Soap Indoor/Outdoor Concentrate! Take pee smell out of everything including grout! I have been doing rescue for 30 years and have tried everything. This is the only thing that truly works. Plus it is totally safe.

Our litter box is big enough for our cat, but when she goes. she sits sideways, so a lot of times she'll pee outside the box. Any ideas?

We had similar problems with our cat who started to pee over the litter box edge and got pee all over our floors and walls. We tried various high-sided litter boxes, but they were never high enough. We finally found this product on Amazon here, which was these plastic shields that we attached to our open top litter box to extend the height by about 10 inches, so far it's working great. Hope this helps! https://www.amazon.com/dp/B09XJHQ7PZ