Fast forward to this past week. I finish up some BIG barn doors of Spanish Cedar. (Is Royal cedar any different? This stuff isn't quite as aromatic as some SC I've worked with). Same design, same issue. This time the doors are to be painted (rather than oiled like the Doug Fir), so we go ahead and caulk the seams and the triangular openings where the panel enters the groove of the rail. They then get primed, and will be painted on site.
For the painted doors I'm guessing the caulk will hold up "fairly" well, but it will most likely fail within 4 or 5 years I'd guess. Is there a better way to do this? My idea would be to seal the grooves of the rails and stiles with epoxy. Then drill small weep holes in the bottom rail. Bevel the the exterior edge of the bottom rail so water flows away. Even slope the groove in the bottom rail so water flows towards the weep holes on the outside. I'm going to Barnes and Noble to do some research, but was wondering if anyone has any ideas. Thanks.