I'm building an 12'x18' freestanding deck.
For support boards I'm joining a 10' to an 8' 2x6 using truss plates. The 8' board is dry and measures are as expected (5.5"x1.5"x8'), however, the 10' boards are quite wet and it's dimensions are enlarged (5 3/4"x1 5/8"x10'1/4").
Should I try to center both boards leaving a step-edged joint all around, or should I join them such that one edge is flush across both boards while the other has a 1/8" step?
Thanks

Hmm. This is a tough one and I don't think I can give you any good advice here. You might want to call the store that you purchased the lumber from to see what they have to say.

Deckman