Replacing Teak Decks . . .
We are just finishing removal of our teak decks. We have a Nauticat and True Blue is right, they are fastened down to a solid fiberglass subdeck (no coring). The screws penetrate the subdeck and eventually leak through. Not as bad as some boats but after removing the headliner in the aft stateroom, there were waterstains evident.
We installed 1/4 inch closed cell foam with two layers of polypropylene cloth. WEST System adhesives and Perfection nonskid surface. Decks are cooler to walk on, cooler inside and they look great. This work was labor intensive but not real expensive. It will make the boat more valuable and extend her life.