Door Rail Attachments and Wood Movement

Advice on gluing large-dimension door rails so as to allow for expansion and contraction of the lumber. October 27, 2009

I am making a 2 1/2" thick quartersawn Douglas fir entry door. The bottom rail is 12" wide on which I am using double 4" wide tenons. How do I deal with wood movement? I know of some door makers who would glue the whole 12" width of the rail. That seems risky to me. I was thinking of gluing the top tenon and pegging the bottom tenon in an elongated hole. What is the standard practice here?

Forum Responses
(Architectural Woodworking Forum)
From contributor G:
You might want to glue the bottom tenon to direct wood movement of the rail upwards. That way if the rail swells it will not change the height of the door or rub too hard on the threshold.

From contributor C:
Your idea is on track. The accepted rule of thumb is to fix the center portion of the wide rail or member with glue and tight dowels or tenons. The shrinkage in measured movement will be one half as much. Think about it. Then the outer third of the wide rails can be doweled and glued. We like to sand a waist on the dowels so the rail can expand and contract a little.

From contributor M:
I couldn't agree more.

From contributor L:
I tend to agree, in theory. But in reality there is probably a center stile that will prevent upward expansion/movement in the door. I would probably glue it solid because of this. Otherwise all the movement will go down and tend to bind the door on the threshold. Unless you were using modern weatherstripping which is about 3/8" tall and ugly as all get out.