Thanks for your ideas.
I've been asking around outside the computer, too. Also been looking at installations, old and new.
I think everyone is right, at the right time. Here's my theories.
Michael hit it on the head for green lumber. It will cup like crazy as it dries out, even in this very wet climate. Not only will it cup and hold water, the decking has a built in see-saw for creaking and working fasteners.
Heart up is the only way for green wood, or heart out for fascia.
The other argument for heart up is when sapwood is present, which rots regardless of species.
Kiln-dried or air-dried, then milled seems to make a difference. Treated decking, which must be dried before dunking in major chemicals, actually cups the other way in our humidity.
As for splinters and shaking, the heart does in some species, treated yellow pine is the worst I've seen, and varies per lot.
As for car deck T&G overhead on ceilings, if it's dry or not, seems like heart up makes sense to avoid shaking and splintering on the visible side, the sap side.
Anyone else have any theories?
Zach
