hello all, I have a dutchwest wood stove with the vent going straight up, replaced last year due to tree falling on my house. my contractor has been here every time it rains heavier than a drizzle to reseal the pipe at the roof fleshing & storm collar. they were just here again this morning to put tape on for temporary seal. my ? is what is the best way to stop pipe from leaking? it seems contractor does not know how to do it.