Gaps for molding on a frame and panel door?

[Michael Panis]

Hi Folks,

This is not a question about leaving a gap for panels on a frame and panel door.

I'm building pocket doors that will (hopefully) match the historic doors in my house. Rather than raised panels, the panels are flat and framed with molding. Pictures are below.

My question is whether I should be leaving a gap between the molding and the rails and stiles to allow for wood expansion. My plan has been to nail the moldings to the door frame (not the panels) and my inclination is NOT to leave any gap. My reasoning is that the tight structure of the door will not allow much expansion inward. I would expect the rails and stiles to expand out. The two lock rails and mullions might expand, but here I would expect them to push the middle of the molding, not the corners.

I would look at my existing historic door for guidance, but over the years previous owners have put enough finish on them that the moldings have become attached to the panels. As the panels moved with the seasons, so did the moldings.

Any thoughts?

---Mike

[Jerry Miner]

Mike--

No need to leave gaps. The door construction will keep the panel openings pretty stable in dimension. It's the panel that can move (if it's solid lumber. If it's plywood, then it will be stable, too, and you can glue and nail at will.

[Mel Fulks]

We used to run a groove in panel opening perimeter. Then put a spline in the groove (dado) that was same thickness as panel edge. Moulding rested on the spline and panel was sized about a 1/16th smaller all around. That allowed some panel movement and kept moulding flat and uniform.

[Michael Panis]

Hi Mel,
If I understand what you are suggesting, instead of the panel actually extending into the frame, only a spline extends into the frame. The panel floats, parallel with the splines, and is sandwiched in place with the mouldings. The mouldings also hide the gap.

Is that what you are talking about?

I don't think that would affect expansion from the frame, but that is exactly what I am doing with the upper panels. They will be glass.

Thanks,

---Mike

[Mel Fulks]

That's right Michael. We just did that with wide applied mouldings ,and company had been doing that for a couple generations and I never saw any returns.

[John TenEyck]

Sort of what Mel said if you are using solid wood panels; put splines in all your frame members, as thick as your panel, and have them project out about 1/2". Then glue and nail your molding into that rabbet on one side, flip the door over, set your panel in place with room for expansion across the grain, and nail in the molding on the other side. If you are using plywood panels there are more options but you could do it the same way.

John

[Joe Calhoon]

We do as Mel suggests. On square stuck doors we always have the groove and just fill it. It is also possible to do a reverse square cope and stick as one of the pictures show. These methods give a good bearing surface that the applied moulding can be glued and nailed to. We never glue or nail to a solid panel but would not be a problem with a ply panel. We Hoffman dovetail the mouldings and apply them as a frame. That keeps the joints tight.
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[J.R. Rutter]

Nice use of the Hoffman, Joe. I've never thought about reversing the cope and stick. Good stuff.