I've been making quite a few exterior doors recently and am wondering about the design and its ability to weather the elements over time. On three different jobs the owner has wanted frame and panel doors, the panels consisting of individual planks with a chamfer of 45d on each edge. So what you end up with is a panel that has a series of grooves running down it. The rails and stiles are made up of stave-core veneered with the respective wood (Spanish/Royal cedar or Douglas Fir). In any event, the panel floats inside the frame, and where the groove from the panel runs into the rail there's a triangular opening the will allow water to collect in the groove of the bottom rail. Even if there was no groove in the panel, water would still seep into the rail at the seem, since it's not been sealed or anything. IAE, I asked if we were putting weep holes in the bottom rail. What about the triangular openings - are we going to plug them? No. Doors get installed, a few weeks later they're being hosed off and water flows down the groove, collects in the bottom rail, and flows out the other side into the house.
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.
JP