In my experience, there is no way to stop a cat that has a carpet ripping tendency. We have a 9-year old siamese (Max) who does it despite all our efforts to stop him. His half-brother (Sam) is no trouble at all and only rips the scratching board. Max though rips the board and the carpets. He seems to be totally deaf if we shout at him when he's in a ripping session. we've tried squiting a water spray at him but that only works till the next time and risks making a mess.
My daughter had an ordinary moggy that ripped the back out of a brand new sofa.
If anyone has any bright ideas, I too would be interested to hear but I don't have any great hopes.
#3 cat, Max, is a lifelong carpet scratcher ripper, and this, along with his dislike of my neighbours dog, is the main reason they didn't object when he decided to adopt me, better my carpets being full of holes than theirs.
Orange peel, or any citrus peel will do, placed in any fav scratching spot works if you can put up with the house looking untidy with peel scattered about. There are various anti scratch sprays available, but the few I've tried had little effect, certainly less than putting pure, neat lemon juice down, but even this is proven less effective than peel.
For all Max seems dead set on digging down to Australia when he's in one of these moods, the damage he's caused pales against that my #1 cat, Bola, caused to the dining room carpet after I accidentally locked him in overnight. He'd been determined to, and damn near succeeded, in digging his way out under the door. I could have cried when I saw the state of the carpet in the morning, but it's taught me to make sure no cats are in any room if I'm going to close the door at night.
Ian