Wish I'd read your post on the undercoat thing BEFORE I glued and screwed those first two pieces in place! The rest of the floor is in much better shape so won't likely have any problem. Oh, well. Live and learn. If I'm back doing this next fall again because of Rot or mold problems I guess I'll do that! I'm hoping a good heavy coat of Kilz (or two) will discourage that for a long time to come. That and of course re-sealing all the edge joints on the pop-top where it appears to me things must be leaking and anywhere else I suspect water will get in.