Student Exchange Programs

I am an exchange student to the US. I don’t know much about the American culture. My roommate gets up early. He enters and exits the room very frequently, about 6 times in half an hour. The handle of door cannot be rotated from outside. My roommate just lets the door close by itself, which makes a big noise to me. I am awakened in this way almost every morning. When I come back to dorm very late, I always keep a small gap at the edge of door, keeping it not completely closed. Thus I can enter or exit the room with no sound. Is my behavior appropriate in the American culture ? Is it common that people shut the door of a dorm loudly ? If so, I will try to get used to it. If not, can you tell me how to say it to my roommate? I am shy.
I just keep a gap when going out to wash my hands or brush my teeth. I will definitely close the door when I’m ready to go to bed. I rotate the handle finally to close it quietly.