Build a stepladder cat tree.,
Convert a bookcase.,
Buy wall shelves for your cats.
You can buy a new stepladder, or you can use a ladder you have lying around. Measure the ladder and the place you plan to store your tree house. If you are using an old ladder, clean it thoroughly before bringing it into your home. You might want to paint your ladder a cheerful color.
Add boxes. Lash or glue a box or two to some of the steps.
Add a pillow. You may want to string up a sort of hammock between the sides of your ladder and put a pillow on it for your cat to sit. If your cat doesn’t like rocking, fix a piece of wood or a platter between the rungs.
Make sure your ladder is balanced. If your cat or cats are sitting on one side, your ladder should not fall over or collapse on them.
, Pick a bookcase you are not using, or buy a new one. If it is sturdy enough to stand on its own, you do not have to modify it much. Otherwise, use furniture straps to tie it to the wall. Cut holes in each shelf large enough for your cat to slink through. Cut carpet squares to fit each shelf, and fix them in place with glue, nails, or staples.
Buy a low-pile carpet to discourage your cats from chewing it. Cut the carpet into squares or rectangles to fit the shelves.
, Sturdy shelves can be fixed to your walls in “steps” or zig-zags for your cats to climb. Measure your cat’s reach and leave the right amount of space for your cat to get from shelf to shelf. Attach cloth or carpet squares to the shelves so your cats can get a grip on them. Add a pillow to one or two of the shelves for cat comfort.
Glue, nail, or staple everything you are putting on the shelves, as your cat may knock them off otherwise.