Solid walnut bedroom door

[Wayne Watling]

Hi,

I'm designing a solid wood bedroom door and wanted to run it past the forum members before settling on the final design. See attached photo for details.

The main question I have is with regard to wood movement, and also whether you see any other issues with this type of design in general.

The 13 inner rail pieces will have 1" deep (1/2" wide) grooves cut on all four sides. I'll use 2 1/8" wide splines to hold it all together, two long splines for the sides (one of which will be glued into the stile. The splines that fit into the 13 inner rail pieces will be glued into one side of the rail only to allow for some movement. I don't anticipate too much horizontal movement because the wood grain runs in all the same direction. There will be movement up and down the door so I was thinking of leaving a 1/4" gap between the top spline and the stile it fits into. To allow for this movement I'd also have to make the 1/8" gap (the gap which visually separates all the pieces) a little wider between the top rail and inner rail.

The main rails and stiles will be milled to 1 1/2" in thickness and the inner rails will be 1 1/4" in thickness.

Thanks for comments, Wayne.

[Jim Becker]

Your biggest challenge is going to be with seasonal wood movement vertically with the "panel" and it's clear you understand that is a factor in that dimension. Side to side is less of an issue than vertically based on the orientation in your diagram. I wonder if T&G with deep grooves and shorter tenons that don't seat fully might be better than splines? You should be able to calculate the wood movement mathematically...I don't have the numbers handy but they are readily available...but it's important to take into consideration where in the "cycle" things are at the time of build.

[Jerry Miner]

You are wise to be considering wood movement here. I had a client once who designed his own door with similar horizontal panels ---but without expansion room---and had it built in a shop in a very dry climate, then shipped it and installed it in a different climate zone, where the panel expanded and pushed the top rail beyond the top of the stiles by about 3/8"

IMHO, a 1/16" gap for expansion at each panel would be plenty (1/16 x 14 = 7/8")

But I think you'd do better to use a T&G joint rather than groove-and-spline. Here's why:

Groove-and-spline will create a small "through-hole" at each end of each panel--where the horizontal spline meets the vertical spline. Light will show through these holes. T&G joinery would eliminate these holes.

[Kevin Jenness]

You would be better served by fixing the rails in place while allowing for movement at each horizontal joint. As it is any gain in moisture content will force a significant vertical expansion in the entire panel area. Assuming flatsawn walnut and a seasonal MC change of from 6 to 10% in a non-air-conditioned space you should plan on movement of about 3/4" (http://www.woodweb.com/cgi-bin/calculators/calc.pl). Your allowance should reflect the actual MC at assembly and the expected conditions in service.

I was involved in building a batch of doors of similar design in flatsawn white oak. We used 14mmx70 Dominos in all the rail to stile joints, which accurately located the rails with a consistent horizontal reveal. We used t&g, but splines are fine if accurately cut to length. I would recommend gluing the horizontal splines in prior to cutting the rails to length and grooving the ends. You could adapt your joinery to achieve the same result by decreasing your horizontal spline width to 2", temporarily clamping your inner rails together with the appropriate spacers, and gluing the vertical splines into the rail ends. I would do that before final assembly, and I would glue the long spline to the stiles as well. You may have some issues with squeezeout given your 1/8" reveal between the rail ends and stiles. Using t&g and spline tenons would economise on labor.

[Brian Holcombe]

Using splines seems ok, but I would probably float the splines and join each plank to the stile. Allow a gap for expansion at each spline. If you want a consistent reveal around the panels then create a small notch at each shoulder that is similarly sized to the amount of the gap left between each panel.

[Wayne Lomman]

I agree with tongue and groove joints all round. To allow for the movement, assemble it with a moderately dense foam strip in the bottom of every groove to take the rattle out of it and keep the joint gaps even. You can get a suitable foam strip that's usually used for draught excluding around windows and doors. Cheers

[Jim Becker]

I agree with tongue and groove joints all round. To allow for the movement, assemble it with a moderately dense foam strip in the bottom of every groove to take the rattle out of it and keep the joint gaps even. You can get a suitable foam strip that's usually used for draught excluding around windows and doors. Cheers

I'll add that I'd probably pre-finish these components before assembly to insure that as they expand and contract, there will be no obvious finish lines.

[Wayne Watling]

Here is a little more detail and info that may not be obvious from the initial post.

A critical aesthetic design component is the 1/8" gap which surrounds ALL components. I don't want seasonal wood movement to change that gap in a noticeable way (I'm probably asking too much with that requirement). With that in mind, the expansion must take place throughout the whole panel area rather than at one end or the other. So each inner rail needs to have room enough to expand tangentially (by a max 1/32", probably closer to 1/64"). This is all kiln dried to 6% flat sawn material and the current household humidity is around 30%. I expect the MC to rise 1-2% throughout the summer.

By using either the spline or T&G method a small hole might become visible on each side (inside the gap) of the inner rail with any expansion. The shiplap method would resolve that but it creates another visual problem, in that both sides (back and front) of the door would look different.


I wonder whether space balls or some of that closed cell weatherstripping material would hold up given the weight of the inner rails, the lower pieces might crush. Another option would be to have a middle fixed rail which would divide the whole problem up into two smaller problems.

Wayne.

Wayne and Jim, I like the idea of the foam.

[Wayne Watling]

I'll add that I'd probably pre-finish these components before assembly to insure that as they expand and contract, there will be no obvious finish lines.

Yes I agree, definitely intend to do that thanks.

[Ben Abate]

Hopefully I'm reading your last post correctly about the stacking of the panels Would it benefit you to affix one panel every so many to ensure all the weight is not always on the bottom panel? Every third or fourth panel be attached by dominos so the Space Balls or whatever aren't crushed? I don't believe it would noticeable if one panel moved 1/64 and another moved 1/32. I love the design

[Brian Holcombe]

Use quarter sawn material and join every piece, as I mentioned previously, and you will maintain that 1/8" space around every piece.

A reveal is furniture/cabinet speak for an intentional gap.

Typically these doors are made with the panel members being the same thickness as the outside frame. It's s very heavy design (literally) but the gaps around the panel members do make it an interesting design.

[Ben Abate]

Here is a thought if wood movement is a worry to you. Now i'm sure you thought of veneering but as I think if it I built a pocket door for our master bath and veneered it. I had a gap the entire way around and used inlays to off set the black gap. With how you are describing the build process you could veneer the panels from MDF and keep a gap as you like. Understandingly my process was a vertical look and you want a horizontal look but I believe you will be less concerned in the end. My door is solid mahogany frame with the MDF core panel veneered with Sapele, Holly and Maple with a painted black gap. And yes the bottom and top rails are mohogany but they lightened up and the flash really makes it look more so than it is.

Just saying.

[Wayne Watling]

Hi Brian,

Quarter sawn material is about 25% more expensive but I think it can be done with flat sawn and the right design. I started the design with a uniform thickness but the weight for the sliding door was going to be too heavy for the hardware I have, and besides I like the appearance of insetting the inner panels by 1/8". I thought of the word 'reveal' too but when I looked it up the definition didn't quite match so I stuck with 'gap' lol.
In your previous post you talked about joining each plank to the stiles, I have an idea which I'll post next, stay tuned. And thanks.

[Wayne Watling]

Hi Ben,

Hopefully I'm reading your last post correctly about the stacking of the panels Would it benefit you to affix one panel every so many to ensure all the weight is not always on the bottom panel? Every third or fourth panel be attached by dominos so the Space Balls or whatever aren't crushed? I don't believe it would noticeable if one panel moved 1/64 and another moved 1/32. I love the design

I do have a Domino but I'm not sure how I could make it work with this design but you gave me an idea.
I'm thinking of pinning every second inner rail through the center with a walnut dowel (visible from one side of the door only) through a fixed tongue. That would hold them in place vertically from where each piece could expand in both directions maintaining an equal sized gap all around, at least visually it would be hard to see any variation. As I mentioned before the horizontal movement is not an issue as the grain is all running in the same direction.

Here is a thought if wood movement is a worry to you. Now i'm sure you thought of veneering but as I think if it I built a pocket door for our master bath and veneered it. I had a gap the entire way around and used inlays to off set the black gap. With how you are describing the build process you could veneer the panels from MDF and keep a gap as you like. Understandingly my process was a vertical look and you want a horizontal look but I believe you will be less concerned in the end. My door is solid mahogany frame with the MDF core panel veneered with Sapele, Holly and Maple with a painted black gap. And yes the bottom and top rails are mohogany but they lightened up and the flash really makes it look more so than it is.

Just saying.

I did think about veneering but decided to explore solid first, I think it can be done with solid. In the end I have veneering as an option if I can't get it to work. Thanks for your input. Wayne.

[Wayne Watling]

I think this will work. A vertical spline pinned through each inner rail by a single walnut 1/4" dowel and seated into each stile. This will keep the inner rails evenly spaced and allow for expansion at the same time. All the gaps will be filled with closed cell weather stripping type material to allow for individual expansion of each inner rail.

Wayne.

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