How do I stop my dog from tearing up the carpet?

Blocking off the area won't work, because he will either somehow find a way to get to it again, or chew on another area of the carpet. DO NOT, and I repeat, DO NOT EVER HIT YOUR DOG! That will only make him fearful of you, if not aggressive. The old method of rubbing their nose in the mess is proven not to work either, because the dog does not understand what they did wrong. Sometimes they do, but they don't speak english. They can only tell one thing. When you're happy with them, and when you're not happy with them. They do not understand what they did wrong at all. To your dog, chewing on the carpet is probably almost like a daily routine. It's something he might do to relieve stress, or a number of other reasons. Try taking him to a dog park to play with other dogs, or take him on long walks to tire him out. If you catch him doing it again, lure him away with a treat, or simply stick a toy right between him and where he is chewing. At some point, he might get the message, or he may not. If you have to, you might have to keep him locked in a separate room whenever you're gone. If he keeps doing it, even with all the distractions you might try, in the end it might be simpler to contact a professional trainer. Either way it goes, good luck. Puppies are very hard work!