On my Beneteau,it's caulking. I just redid the swim platform on my boat which was essentially a teak surface glued to the Fiberglas deck. The glue was coming loose, so I peeled it up completely. I was surprised to discover that it was comprised of individual solid teak strips and not a laminate. The caulking was easy to peel out as it was fairly well aged. After I reattached the teak which was held together from the underside with staples, I re caulked everything. I masked all of the surfaces where I did not want caulking (the stuff is messy), caulked all of the joints and the perimeter. I smoothed out the joints with a wet finger,wearing latex gloves. I peeled the tape after about an hour, and the joints came out perfectly. It looks like an original factory installation. It's still a pain to do.
I'm tempted to say that my next boat will either remain "tearless", or I'll have to get rich so I can hire someone to do the maintenance. I'm getting to old for this, and my sons live too far away to help....