Doing a tub room addition cabinet . I purchased two raised panel tall and narrow cabinet doors last month. Both about 11 inches wide. One is 2 ft high, the other about 4 1/2 feet high. Oak. They are painted now . The 4 1/2 ft high one has warped out away from the cabinet at the top and bottom about 1/8 – 3/16 inch. the other one is still flat , as are the old matching ones in the same room (15 years old) and all the cabinets at my moms house – perfectly flat – 40 years old.
What causes this warping????
Replies
Wain,
There's numerous potential causes for this. Here's a couple…….
1- If the cabinet on which it is installed is not vented to, or insufficiently vented to, the room in which it lives……. the air exchange and consequent humidity levels will be different on the two sides of the door and voila…………..over a period of days and weeks, the door warps. Actually, it's the panel doing the warping in the case of a frame and panel door. This would occur in an unvented cabinet even if the wood was at EMC to start with. The effect is going to be more pronounced in a bathroom situation and I'm sure you can see why.
For cabinets that must live in an environment of changing humidity levels and/or those cabinets which will not be open or closed much, I always figure out a way to provide passive venting in the interior of the cabinet to insure that this humidity related warping doesn't take place. On kitchen cabinets tho, I usually do nothing for passive venting because the opening and closing of the doors and drawers during the course of the day/week provides for sufficient air exchange.
2 - If you used a latex primer and paint, it is absorbed into the wood cells causing them to swell and then when it dries……….voila……the wood is now set to this condition. You must realize that the wood lacks total cellular uniformity (it will absorb different amounts in different areas) and that the application of the latex paint will not be absolutely uniform and consequently the door can/will move as assuredly as if you'd sprayed it down with a water mist.
Depending upon what has occurred here, it might be possible to get that door to straighten out some or all, by simply letting it stand open for ten days/two weeks. If this resolves the warping, then I'd try to figure out a way to provide cabinet venting to the room so that it doesn't occur again. Frequently, this means doing some sort of decorative cut out, but you may be able to provide unseen venting depending on your particular situation.
Generally, the larger a door is, the more prone to this phenomenon it is.
The reason the 40-year-old cabinets are straight yet may be because of venting (passive or active) or the fact that they may be finished with shellac, which is a great barrier against water vapor exchange. I wouldn't use it for the finish coat in a bathroom setting because it has little resistance to damage from water droplets, but you could apply a coat or two as a sealer/primer and then apply your topcoat of choice over that. I'd advise that if oil-based poly (an excellent choice for a bathroom) would be your finish of choice that you buy dewaxed shellac flakes and mix your own or buy shellac off the shelf. If you buy off the shelf, pour the shellac into a lidded glass jar (store in a dark place, not in direct sunlight) and wait about a month for the wax to settle out. Then using a turkey baster or the like, draw off the good shellac from the top leaving the wax undisturbed on the bottom. Using "waxed shellac" can interfere with the adhesion of oil-based poly. Better safe than sorry.
Knowledge is power, but only if applied in a timely fashion.
Edited 12/23/2002 11:20:49 AM ET by GOLDHILLER
Goldhiller,
I enjoyed reading your post. Are you a painter? It seems you've spent a lot of time analyzing this problem, and in your opinion, it seems to be a question of proper sealing of the wood, and venting.
As a woodworker, my knee-jerk reaction was to analyze the construction of the door. For example, is it a true floating-panel door, or just some sort of solid construction that only looks like a rail and stile door with a raised panel. Also, I would have looked at the cut of the wood: is it plain sawn, or quarter sawn, since quarter sawn seems to be much more dimensionally stable. Finally, I'd wonder about the moisture level in the door components at the time it was fabricated (i.e., was it still a bit on the wet side?).
Have you explored these wood-related factors as well? Are they secondary to painting/sealing issues? I'm interested to get your input on this, since I'm always looking for ways to improve the quality of my work.
Thanks,
Ragnar
Thanks.
The wood seemed dry when i got it. It true raise panel with floating center panel. Do not know how to determine how it was sawn.
My guess its the humidity difference problem. I can vent the cabinet without ruining it. Odd the 2 foot high one is still flat tho??
The non warped 40 year old cabinets were in a kitchen, and were also well covered with some type shiny "varnish".
I will try leaving the door open and apply some clamp force to try to bend it back.
will also add the vents
any other ideas?
Thanxxxxxx!!!!!.
Wain,
This is just for academics, seeing how your oak is already painted....
But you can tell the difference between quarter sawn and plain sawn lumber by observing the grain pattern on the wide face. If you see lines which resemble a topographical map, it's plain sawn. If the lines are straight and parallel to each other, it's quarter sawn. Oak, when quarter sawn, will also show "ray flakes" (part of the grain structure of oak). This type of wood is what some people refer to as "tiger oak".
In softwoods, quarter sawn is the same as "vertical grain", and plain sawn is the same as "flat grain".
Typically, quarter sawn (vertical grain) is used for door rails and stiles, since it is less prone to warping, cupping, etc.
Ragnar
Your knee-jerk was the same as mine. My first thought was about the milling of the door stock, and whether or not the wood was seasoned/acclimated properly at the time of assembly. It's been my experience that interior cabinet venting is not an issue unless lighting or heat source proximity(ovens) come into play. In *this* case, the door is in a bathroom(I think) and any moisture conditions would be outside the door. If the door was taking on moisture from the exterior side, the bow of the door would be the opposite of what was stated.
You are correct - is in bathroom tho a big one but not in the shower room (next room).
Bow out is at the top and bottom, bows away from the face frame.
If the door is taking moisture on the exterior of the door, it would be bowed in at the ends as the unequal moisture expands the outside of the door.
In spite of all the other good info shared here on this subject, it has been my experience that the taller a thin cab door is in relation to it's width, the more likely it is to warp. I've had quite a few at 14w x 39h take a yank. I also buy cab doors from a company. They will make them as big as you mention but won't gaurantee them over a certain H/W ratio. I know because I did one with them abouyt the size of yours and had to sign a waiver and take the risk myself..
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
you're right about the H/W relation and tendencies to warp. On taller doors it helps to use thicker stock to help resist warping or twisting. Many times additional hinges will keep a tall, narrow door flat.
Ragnar,
Thirty years ago, I made my living primarily as a furniture/cabinet maker but I was also fabricating custom architectural millwork on request. About twenty years ago, I began branching out into the remodeling, renovating and restoration of homes as I had become somewhat bored with just building furniture and cabinets. And I wanted bigger things to build, I guess. Today this includes most facets of homebuilding/restoration/remodeling, exclusive of major concrete projects (as I can't justify the expense of a backhoe and forms) and we (there's just two of us) don't install HVAC as a normal business service. I still build furniture and cabinets for my clients on request as well as for friends and myself……primarily during the winter months.
When it comes to furniture, cabinets, or most any article made of wood…………. engineering, finishing and venting are pretty much inseparable if you want the piece to "behave" and survive intact for generations. Do these things well and success is at hand. That last statement is based on the assumption that the wood you are using is either kiln dried or at EMC when you begin and that both sides are evenly exposed to the atmosphere during both the milling and construction phases of the project. For instance, don't stack those boards dead on top of one another while you go do something else for even a couple of days or you may well live to regret it. These are a number of fundamental lessons that one learns early on if you're to become a successful custom fabricator as there's no one else to pass the buck on to, if the final product is "wanting" as regards warping, cupping or splitting itself asunder. The wood will let you know if you're treating it appropriately or not and it doesn't give a hoot how long or hard you argue with it or what your plans may have been.
I only spent perhaps a minute analyzing Wain's problem as I've seen this sort of thing over and over again and it's based on pretty simple to understand principles of wood physics. My own early ill-conceived pieces and projects suffered from such fates until I learned. But yes, my response to Wain was "shooting from the hip" and based on a few basic assumptions including that the wood was evenly dry on both sides when he installed the doors. To do otherwise would have meant an even longer post. Let me say this tho…….. even an originally flat plywood door will have the same response resulting from uneven moisture exposure…….just to a somewhat lesser degree , which may or may not be controllable by the frame in which it resides..........depends on the thicknesses of the parts involved and the differential of moisture. After all, plywood is still comprised of wood cells.
And I'll add this……….I think that "shiny varnish" he's referred to may likely be shellac because that's what it looks like. A test in an inconspicuous area with a little denatured alcohol on a rag will tell him. Alcohol dissolves shellac, usually in a minute or two. Another possibility, judging from the age of the cabinets, would be spar varnish, which wouldn't readily dissolve under the alcohol.
Then again, you may know all this already.
Knowledge is power, but only if applied in a timely fashion.
In the future if I want a latex top coat what do I seal it with?
Thanks for the details in your post.
Wain,
A coat, or better yet........two coats, of oil-based primer should help prevent the absorption of the latex paint into the wood and will provide a better vapor barrier as well. I have a number of true frame and panel cabinet doors in this house that are 14" wide by 72" tall that remain dead flat year round although they have a latex top coat. Oil primer was used and the cabinets are vented.
Back on the subject of venting….vents needn't be huge or unsightly and can usually be hidden from view with a bit of planning, but again not all cabinets will require them. Sometimes the necessary venting can be incorporated into the design or is already inherently provided by the design of a piece and so nothing further is necessary.
Whether or not a cabinet will require passive venting is something I determine kind of on of a case-by-case basis if I can know or imagine ahead of time whether or not a sufficient amount of active venting will take place. But one thing is for sure...it never hurts to provide for passive vents and should be seen as an insurance policy against cupping and warping. In a bathroom environment, one can expect large differentials of water vapor and so the proper choice of finish and the consideration of venting is ever more important. Even the proximity of a cabinet to a shower stall will effect how much potential exists for undesirable consequences. The closer the cabinet is to the source of the steamy air in the bathroom, the more you're asking of the finish in resisting absorption. Consider too how much difference there would be between a bathroom that serves two adults and one that serves two teenagers known for their hour long hot showers. Sometimes we're asking a lot of the finish and the wood.
Consider that theoretically, one should be able to take a piece of milled flat lumber and hang it from a cord in the center of the bathroom, devoid of any finish whatsoever and that board would remain flat all year around.
Here's one to chew on…….you can theoretically even out the moisture absorption on interior and exterior of a non-vented cabinet whose doors are not often opened simply applying more coats of the same finish to the exterior than to the interior.
Knowledge is power, but only if applied in a timely fashion.
Wain, ignore all the above. Most problems like this are caused by not holding your mouth right.
Joe H
As a framer I should probably stay out of a discussion on warped cabinet doors. After all my remedy to the warped door would be to nail it shut on the high side and wedge it out on the side that is touching and let it set for a few days or longer. Framers don’t work with perfect wood. If we had wanted perfect wood we would have left it in the forest! I would guess that the wall the cabinet is mounted to is actually “to straight”.
Mr. Jalapeno
" I would guess that the wall the cabinet is mounted to is actually “to straight”.
That's a good point, and something that should be checked *before* the cabinet is installed, but may be part of the problem. When I build cabinet doors, they are glued and clamped in a flat frame, and checked for flatness after initial sanding. If they aren't flat then, I won't waste anymore time on it and make a fresh one. If the cabinet when mounted in or on the wall has any twist to because the wall is out of plane, it shows up in the doors(I'm talking inset doors here). There are some tricks to compensate for minor cases of twist, but I'm sure you know this already.
Trying to reverse bend the doors would most likely be only a temporary fix.