Cats love a bit of the outdoors, so to provide it in a safe manner - where they can't escape, and other cats can't get it - we have 'meshed in' our courtyard. You can get professional cat-mesh jobs like these guys (and many more - just google), but we rent. So we had to come up with an option that did no damage, could be taken down when we leave, and was cheap. It also had to be STRONG.
It has taken several iterations to achieve Alcatraz. I have never before seen a cat traverse across a ledge, hanging by his front paws and swinging the dangling body side-to-side in order to inch across. And then chew through 5 layers of bird netting! I even know of a Korat who chewed through the professional cat mesh. The upshot is that we now have chicken wire. It is nailed into the wooden fences, and strung along the walls via wire that attaches to metal stakes. We used zip ties to 'knit' the chicken wire together, including an intricate lacing through the tree branches to eliminate that escape route. (Our first blocking attempt was a bin lid ringing the trunk, but after 9 months, smart Kato figured out how to somehow get around it.) The courtyard is now the perfect outside retreat and is much loved by felines and humans alike - the humans like it because it is one more element that makes for a contented cat.
It has taken several iterations to achieve Alcatraz. I have never before seen a cat traverse across a ledge, hanging by his front paws and swinging the dangling body side-to-side in order to inch across. And then chew through 5 layers of bird netting! I even know of a Korat who chewed through the professional cat mesh. The upshot is that we now have chicken wire. It is nailed into the wooden fences, and strung along the walls via wire that attaches to metal stakes. We used zip ties to 'knit' the chicken wire together, including an intricate lacing through the tree branches to eliminate that escape route. (Our first blocking attempt was a bin lid ringing the trunk, but after 9 months, smart Kato figured out how to somehow get around it.) The courtyard is now the perfect outside retreat and is much loved by felines and humans alike - the humans like it because it is one more element that makes for a contented cat.