Planning to make a 3-layer exterior door

[petertay15]

Plan to make an exterior door, something like this photo. I'm assuming it needs a middle layer for strength. Would 1/2 inch or 3/4 inch BB plywood be a good choice? If so, should the outer layer boards be glued to the plywood? Not sure how to allow for seasonal expansion with boards on plywood.
Thanks for your thoughts. --Peter

[JGrout]

here is how to do it

[petertay15]

Thank you for the link. --Peter

[jteneyck]

I'm building an exterior door right now following Joe's basic process.  It's very straight forward and the stub mortise and tenon can be cut with a dado blade, no fancy tools/machines required.  Now that I'm building one like this I look at every door I pass to see how it was made.  To my surprise, most all of the exterior doors I saw during a recent vacation used some variation of the applied moldings Joe uses to hold in the panels.  I always thought the panels were captured in a dado.  Nope, they use a much better approach.  As Joe pointed out, the moldings allow you to prefinish the panels and around the inside of the exterior moldings before installing the panels. 

I think Joe described gluing and nailing in the inside moldings, but I plan to screw them in place so that the panels can be removed for refinishing, or replacement should that ever become necessary. 

Some of the doors I saw were in the "cottages" in Newport, RI, you know, the ones built by the Vanderbuilts and their friends around the turn of the 20 th century.  I was really surprised to see that every door I looked at was some kind of stave core construction meaning they had veneer skins glued onto the stiles; couldn't see the edges of the rails so I don't know about them.  I don't what kind of glue they were using in the late 1800's, but it was good enough to survive until 2017.  

John