I pulled the rear corner caps off the roof of my 2006 Fleetwood Santa Fe to see where the dripping water was coming from. What looks like plastic duct tape covers the big holes in the roofing material at the corners. Is there a better material or technique for closing these holes than duct tape? Any suggestions for sealing material to use between the aluminium roof and the plastic corner cap would also be appreciated. I used Geocel Pro Flex RV for the Yakama rails to roof seal and results seem good. I would like to stay with Geocel in other parts of the roof if possible.