I am going to tear out the nasty-looking framing in there now, and redo it with some nice poplar. I was thinking of taking 2 1"x8" by poplar boards and putting a nice graduated routed edge on each of them, and then gluing them together, such that I'd have 1.5" on each side of the opening, bringing it down to 72".
Will the glue hold the pieces together? Of course I'll tack and screw them as well, but I want them to look like one piece with no separation. The area is covered by a large overhang, so it only gets splashed rain from the patio, hardly ever direct rain.
Should I consider a polyurethane glue instead?