Hello all. I am currently in the process of replacing my a/c with a 2 stage Trane package heat pump. The contractor is installing a roof duct to set the unit on. He says that he can do it without aroofer, but I am concerned because he will have to cut a hole in my roof over my den and I would lose a lot in case of a roof leak. Is this something a/c companies usually tackle on there own, and what steps should he take to make sure that it is done correctly? thanks for your replies.