I wanted a door that was easy to seal, thick enough not to have warping problems, large enough to pass through easily and have a more secure lockset. It is simply two pieces of 1/2 inch birch plywood laminated together with 1x2 trim all the way round to cover the plywood edges and stiffen it up a bit more. It's a little on the heavy side but swings nice, has nice solid shutting sound and helps with tongue weight. The wife appreciates the locks.
The little overhang trim over the door helps divert rain. The underside of the overhang has a 1/8" groove cut into the underside to keep the water from creeping toward the door gap.
