Sealing edges of trailer. What putty or caulking do you use?

Butyl tape is good for about 10 years then should be replaced. Both under the trim and around the windows. In the interim, screw tightening every year will help prevent leaks and prolong the life of your RV. The trim strips can be removed after pulling the "RV Vinyl Insert" out. New butyl tape and new "RV Vinyl Insert" are inexpensive. Lots of screws will come out too easily.. Use toothpicks and carpenter's glue to restore the screw holes so the screws will bite...new screws are a good idea, too!