I've been agonizing over whether I did the right thing when I spread 5200 over a long crack in the skin of the deck just after a downpour. I had been hoping to do it after a bit of a dry spell, but none had been forthcoming and in the meantime the darn thing gets another soaking 2 or 3 times every day. So I finally just did it.
Did I seal in a bunch of water which will now destroy the rest of the deck coring?
Maybe so, but I don't know that there was any better option available to me. Well, we'll see. Maybe it'll be a good DIY project to tear it up and replace the core in couple months if things get a little drier