The really important parts are the protection of the cats from predators and the weather, and their ability to come and go in it, as they please. That frame is a short term solution that can work very well, if you site it correctly. Long term, a pergola screened porch type structure attached to the home, with a portion of it roofed, and a portion of it open, would be the best for humans and cats to enjoy the outdoors together.

Your pic really frightens me for the welfare of your cats. Poor kitties, this looks akin to locking them in a hot car where the temps will climb and there is no escape for them. Even on a 70°F day, in a car it will take only 20 minutes to reach 100°F inside; your arrangement may add another 10 minutes. Without conditioning the space with A/C, there is no material that will protect them from the outside heat combined with the cement walls and stone ground. Just drop the entire idea, OK? I really think your cats could die in there quickly on a day that is just 75 degrees, much less Arizona hot.

Deer netting is a relatively inexpensive covering that cats shouldn't be able to go through.

I agree with some of the above concerns, but will add that what you really need to do is have a situation where you have a concrete or fixed base for the structure. My neighbor has a chicken coop that coyotes/raccoons/rats have breached at various times. They had to pour a concrete "rim" around the enclosure, deep enough that burrowing wildlife couldn't breach it by digging, and anchoring the enclosures on top of the concrete. I wouldn't underestimate coyotes, especially. And yes, using the wire mesh that Verbo recommends.

Her beautiful chicken coop has a tree over it, as well, for shade, and I'm sure you plan on providing plenty of shade, and water for your kitties as well. I can tell that you love and care for your kitties.

"I'm sure you plan on providing plenty of shade, and water for your kitties as well. I can tell that you love and care for your kitties"

@Mrs. S - the OP's pic of the site shows no opportunity for shade whatsoever. And, as @User pointed out, the OP's selection of site for the Catio shows no grass or soil, but all rock and stone, and it's "a horrid location for a cat there, stuck between 2 heat holding wings of a house with no breeze". Please say where in the OP's posts that you "can tell you love and care for your kitties". I am seeing a heat trap, and no consideration of what this enclosure will be for the cats.

Can't see the other side of the yard, but what will the cats be looking at and watching? It appears if you add a shade cover on the arched roof, they will not be able to see up over the fence into the trees, because I'm thinking an opaque cover would need to extend all the way down to the horizontal bar to wrap around it to keep it tight, which would cover most of the opportunity to look out when they are up high on whatever stands/towers you furnish. Unless you just want to bungee cord a tarp and look jerry-rigged.

Another thought, since the space is so big for domestic cats, the tubing enclosure can just have wire/screen mesh on the entirety. Then your stands/towers inside it can have the real roofs. With an open roof the tubing can be used for hanging plants and stuff for human use while reducing the scale down for the cats.

Though if Murphy and KitKat are Bengal Tigers, I got nothing.

I appreciate all the people who responded, thank you. Honestly my only intention for asking was to gain insight on good materials to enclose the frame in the photo with. The photo was intended to give a better insight with a visual of the Frame only. It by no means implied anything further was set in stone already. OF COURSE, they will have SHADE. Yes, they will have all the fun\functional\ comfy amenities we can provide for them. We aren’t just throwing them out of the house into a cage to not bother ourselves. Murphy WANTS to be outside all day. I’m doing my best to find a good compromise so HE IS HAPPY. He is used to living in a forest with MORE REAL wild PREDATORS than people around him. He goes in/outside all day long, I am his own revolving door service. He is very vocal on it! And it’s his CHOICE TO GO OUT. We have done this for 13 years & he has survived just fine. I with out fail make sure he is inside every night at dark. My neighbors know him. And are well accustomed to hearing me calling him to come home at the top of my voice. He has given me a few times He scared the begeezus out of me, missing curfew & coming back a little late. But never has he been hurt. BUT .. We have to be in the “city “ now for a while. It’s too dangerous to let him roam outside of the back yard on his own. Like he is USED TO. I fear people hurting him more than I had to fear the chance of mountain lions getting him at home. I love this cat. I saw a graphic online that said “I would throw people in front of Zombies first, in order save my cat “. It made me laugh because it’s TRUE. I totally would for him. So everyone please let your concerns for the cats being some how harmed by our stupidity. Of not giving them shade... or grass or whatever else. Please rest assured these are two very much loved, protected & are healthy happy kitties for good reason. I just needed help because I’m not familiar enough with the materials out there to know which is the best one to pick. For just an example: I think chicken wire could “work” but I know after a while it begins to look pretty “ratty”. Just From seeing people’s chicken coops over the years. I don’t want that. But I’m not financially able to spend a small fortune on this temporary structure either. Nor do I have a lot of construction experience...there is some + good common sense usually. Like I know I need to fabricate a door/gate on one end. But I have to figure out HOW to do it first.. I don’t just already know how to frame it in. And nor do I already know what kind to get. Or if the affordable one I see on “Offer Up” can be modified to work either. Without creating an even
Harder task than it’s worth. I’m trying to avoid costly mistakes of having to figure it out wrong as I go ...starting at zero.
So please if I don’t respond directly to all things asked or incorrectly assumed, it’s not personal. I still appreciate the sentiment. That being said now.. I do have some individual reply’s to make. My sincere Thanks to all! 😊

I also am in Arizona. I had cat fences in Utah before living here but it was a lot to maintain after snow. So, what I did at this house was screen in a covered back porch and have a lot of cat things out there for them to climb on and go to and it's much easier. I had the company who did mine use animal screening so they cannot scratch it up and other animals can't get to them. So ask about that where you shop for it. It's just called "animal screen". You could put that around the entire thing along with something else over the roof part for shade. I have a ceiling fan on my porch but it gets up to 120 here in the summer and those cats still like to be out there. I have to make them come in during the middle of the day in summer because it scares me. Just be mindful that they don't always know what's best and maybe make them come inside for part of our brutal summers. I think the animal screening will work well for you.

Fantastic idea - using the green house frame. FWIW, these are actually cheaper than the wood catio kits. Google deer fencing - deerbusters.com is co. I bought from. This is a heavy black plastic mesh with 2x3 squares that will last forever, affordable, and easily zip tied to structures. Its not the flimsy easily ripped animal fence sold at big box stores. Check out aluminet reflective shade cloths for draping over and attaching to the top during hot weather. These are amazing- I use them over my car for car camping in the summer and they actually work. I would not use them or any other fine mesh directly over the frame as ambitious cats could probably climb or rip them. They cannot climb the deer fence - too wiggly to get a foot hold. YOu could also get clear plastic tarps to have on hand for rainy periods! You can either attach the strucure directly to house or buy or construct tunnels from say a basement window to the enclosure. Cats soon come to appreicate that its their own space, and if they are free to come and go on their own schedule they will love you for it! Be sure to have multiple levels inside for cats to climb. Include potted edible grass and catnip (be sure any other plants are not toxic to cats). What fun! Please post your progress and/or final result!

ETA - just read your story about Murphy and just wanted to add that I so appreciate what you are doing to give this cat a great life. I think above posters like many of us are just cat lovers and worry worts- dont forget other people are reading so the cautions while not applicable to you are good for anyone thinking of building something similar.

Your cat sounds just like my Orange, who had a life of roamiing and sowing his wild oats prior to being picked up, thrown in the slammer and neutered, prior to my adopting him. He could not adapt to being indoors the rest of his life - he tore out screens and jumped off roofs to get outside, once injuring himself.

The first three hours in the new catio he inspected every square inch looking for the way out, and when he couldnt find it he immediately settled down and was as excited to go out in it in the morning as he was to roam around the neighborhood. I think he liked the security and other cats not being able to get in. Once the door was left open by mistake and I found him sitting in the doorway just looking out! He even caught mice in there.

My animal screen isn't flimsy. I've got one hard hitter that is determined to get out, and has escaped and clawed many enclosures in the past., but he can't tear this one up. So, I'm sure there are different degrees of quality. I had a screen company do mine so I don't know where they got it from. It's black and feels different than a screen but looks like one.