Step1
Design your cat jungle gym on paper. Before you do anything else--even before you buy materials--know what you want your jungle gym to look like. If you have a design in your head, committing it to paper will help work out the kinks. Do an image search on the Internet and browse some pet stores for ideas.
Step2
Purchase materials from your local hardware store. The amount of material and the money you spend will depend on how serious you are about your jungle gym.
Step3
Build a large and heavy base. This is extremely important! People build cat jungle gyms themselves for two main reasons. One is money and the other is their distrust of the strength of a store-bought gym. Use a cheap, thick wood for your base. Plywood will work as long as it's more than 1/2" thick. Pine will also work, or just about any wood that's strong and thick. It is a good idea to glue or screw two or more pieces together. Cats can be rambunctious when they want to be. A solid base will allow the cats to play rough without injuring themselves.
Step4
Construct the first and second floors of your jungle gym. Screw the wood you have purchased in place, testing its strength as you go. If you are building a square, box-shaped room in your jungle gym, make sure the wood you use is secured in the base. As with the base, any kind of wood or hard cardboard can be used, although for this portion of the jungle gym, 1" x 2" or 2" x 4" boards seem to work well. As long as you have a heavy base, you are free to construct the cat jungle gym you have envisioned in your mind (and in your drawings)! Just don't build too high. Many cat jungle gym experts discourage more than three floors. Even the most stable base will weaken the higher you build.
Step5
Use your imagination to incorporate cardboard into your cat jungle gym. If you have access to a thick piece of tube cardboard (such as the kind you might mail posters in), this will work well as a scratch pole for your gym. Secure the tube cardboard in the base. Also, cats love to hide. If you have a more flexible piece of cardboard, create a cylinder-shaped tunnel for them to play and sleep in. Just make sure your holes are big enough. Allow a hole at least 6-7 inches in diameter, more if your cat is chubby!
Step6
Cover your entire cat jungle gym with carpet or a similar material. A strong glue is best for attaching the carpet, but a nail gun will also work. The combination of these two things is probably best. The carpet will act as both a safety pad and a scratch pad.
Step7
Go over the entire jungle gym very carefully before you allow your cats to have their fun. First, make sure all the pieces are secured to the base and that no wood or cardboard is loose. Second, ensure that all the carpet has been properly attached and is free from wet adhesive or nails sticking out. Finally, run your hands over every inch of the cat jungle gym, feeling for snags, pokes, splinters, sharp corners or edges.
