Tall Cabinet doors - Warp prevention

We have a pair of 8'x4'x4' built-in cabinets flanking our fireplace. It's an old house and when it was restored about 30 years ago, they made 8'x2' doors out of tongue and groove siding to give is a rustic look. As you might guess, the doors have warped and will not close properly.

I'm going to rebuild them inside and out. One will become a wine bar and the other just storage. The new design will feature 2' 6" doors on the bottom, 4' door in the middle and 1' doors on top. Face frames will consume the missing 6". Planned construction is 1x3 rails and stiles with a 1/4' plywood or MDF insert. The 4' door will have a center stile for extra support and I plan to use three hinges.

My question is will this be sufficient to prevent the large doors from warping over time? If not, are there any good solutions/techniques.

You are on the right track with all that you describe at least in regards to down sizing the doors. Next to the fireplace is the real cause for drama. Likely you get a pretty extreme change in moisture content from summer through a winter of fireplace use. It will be wise to start with 5/4 stock (or heavy 4/4) and properly dress that down to your finished thickness. You will need to flat joint your stock. The flatter and straighter your frame stock the better your end result. This kind of goes without saying but surprisingly folks seem to think they can buy 1x stock at the store and build nice straight anything 3/4" thick.

Also, I would be inclined to use 3/8" or 1/2" panels - MDF before plywood. The chance of getting flat 1/4" plywood panel is not great and a twisting panel will have an effect on how the door hangs. You don't say if you are building inset or overlay doors but next to a fireplace I think the overlay doors will hide more error (if it develops). One more thing is to plan what you will use for catches. Unless you are using self closing euro hinges, a top and bottom catch (at least on the taler doors) will be well worth the effort. There is no shame in needing to use a pair of good catches :). Finally a proper paint job or other finish will help mitigate the extreme conditions. Be certain to properly seal all your end grains and even coat your solid stock face, backs and edges.

Thanks Sam. That all makes sense. I was definitely leaning toward MDF. The mounting will be inset as that is the style of the original cabinets and we are trying to restore the original look. I will use catches though as that is also consistent with the original.

One other question... Biscuits versus mortise and tenon? I have a new biscuit joiner I've been wanting to try.

I love biscuits but not as a door frame joint. I think there is at least one Creeker who will tell you great success stories using biscuits that way.

The kitchen cabinets in my house use an interesting technique to avoid warping. I've not seen it elsewhere, for reasons that will be clear, but it might be applicable to your situation because it does have a rustic look. I'll try to describe. Build a standard solid glued up oak cabinet door (overlay). Mold any desired decorative profile on the edges. Now, using a very thin kerf (1/16) slitting saw, kerf the panels from top to bottom with the depth set to about 2/3 panel thickness. The kerfs are spaced variably about 3-4 inches apart. now flip panels over and kerf the back the same way, with each kerf on the back about 1/2 inch over from the kerf on the front. Finally, screw horizontal battens to the back of the door. The pairs of kerfs, one on front, one on back, provide flexibility in the panel and allow the battens to hold the door dead flat. The doors are stained a very dark brown, and each of the kerfs is chamfered slightly. The effect it gives is reminiscent of a shutter made of separate boards battened together. It's definitely rustic, but attractive in the right setting. I have several tall pantry cabinets with doors that are 4 or 5 feet tall and they are dead flat summer and winter. I know this cries out for a photo or sketch, and I can post one when I get some time if there is interest.

Paul F.