The ends of the weatherboards, where they meet the corner/end-cap trim, needs to be sealed with polyurethane prior to painting, for weatherproofing.
This is essential, but a pain to do. Its hard to get it neat on the under edge of the boards, and its a bit tedious. Oh well, you’ve just gor to do it right if you want things to last.
I tried several tools to smooth out the goo, but in the end a finger is the best. All the nail in the trim needs to be punched in and filled also. I am using a exterior filler that is sandable and paintable.
