Tape covering joints on outside of MH

I have a 2000 Harney Riata. It is made with the bottom half of the coach made first and set on the chassis. Then the top half was made and set on top of the bottom half. There is a joint where they come together and there is a 1/2 inch wide white plastic type tape covering this joint all the way around the motor home. I would like to replace a 12 foot run of this tape but I don't know what it is called, or what to order. I asked Camping world what it was called but they were not much help. Can anyone tell me what the official name of this is so if I ask someone they will know what I am talking about? Thanks for all replies. Gary