Cat Deterrent

How I can prevent my cat from scratching at the door of my roommate to get in? I tested the deterrent sprays.
My cat has always had problems with the doors closed. I am sure that is something territorial. However, when my roommate moved, she keeps her door closed. So my cat sitting and meowing loudly (which is the only time he meows) and scratches on the door to enter I have tried to deter spray, put aluminum foil and double standards pages, but nothing works. I even tried to barricade the door with something, but ends up finding out how to upload it or behind it and keep scratching. Treatment putting it in my room, but he scratches at my door to let out and the carpet is stolen up in both places. My cat will not so this behavior. Please post any advice or suggestions. I am getting my last nerve at this!
go to a pet center and buy one of these zero positions of great things throughout the game for him, if fails, then there is much you can do but let out into the street, the concrete way, trees, fences, etc, etc gring help for their claws.
Cat Deterrent