The problem: The door slab on a 8′ high front door with 3′ radius top unit has bowed out to the exterior of the house to the point that the door is very difficult to close. The door slab and frame were produced from a local door and millwork shop. The slab consists of 1 3/8″ white pine boards glued together with V-grooves 6″ on center. Because this unit is for the front door, I knew the slab would be subjected to different moisture contents on either side of the door. To further complicate things, the front door is set back approximately 4′ from the front of the house in a 3-sided all stone covered entryway. The lot is heavily populated with trees and the house is located in a very humid climate. I took precautionary measures regarding the door slab during the construction of the house. I kept the slab in my heated/cooled garage until 2-days before the painter needed the slab. The slab was stained and sealed on all exposed edges before installation in the doorframe. Despite careful handling, the moisture and air temps have caused the door to bow significantly. Unfortunately, the door style contains no horizontal braces or rails to keep the door straight across its face.
Anyone have a similar problem, along with advice on how to straighten and stabilize?
Replies
Scooter,
Sorry about that, but it's a common occurrence with exterior slab/solid wood doors. Hence the development, adoption, and popularity of the frame and panel door. Even frame and panel doors alter their shape and dimension to some degree when exposed for long periods of time to a humidity differential such as you describe.
If you live where this difference exists all year round…………..not good………at least not for getting that door to behave itself.
Out of curiosity, how long did it take for the door to achieve it's current condition once it had been hung?
Is the door made of quartersawn stock?
Sounds to me like you already know the causes of the problem and therefore already know the cure……..the moisture content of the wood must be equalized on both sides of the door. No amount of any finish can completely eliminate the phenomenon that your door is suffering from, but only forestall its arrival. If the condition of high exterior humidity is only seasonal , forestalling it may be all that's necessary. Before it could have its total effect on the wood, the humidity condition would begin to reverse itself and alleviation would be at hand.
Since your door is recessed and not exposed to rain or UV, multiple coats a high quality oil-based poly should serve you as an effective moisture barrier. I would never recommend this for an exterior door that is exposed to rain and/or UV, but your situation is different. Sikkens varnish would also be an excellent choice as would spar varnish or an oil-based marine varnish. Remember………….equal coatings on both sides of the door. In this case perhaps four coats of finish.
Shellac offers very high resistance to moisture vapor, which is what you're after, but may not be a good choice of finish if the door ever gets wet with water droplets as it responds badly to water droplets. Yeah I know, sounds contradictory, but those are the facts.
No matter what finish you choose, you must make certain that its compatible with the existing finish if you don't strip the door first. Check with the maker of the door if they did the finishing.
The first thing you need to do is return the door to a flat condition prior to adding any type of finish. This, I suspect is going to require that you remove the door and store it in a lower humidity environment until it once again flattens out. If you do remove it, you can get it flat again faster by removing any finish that's on it now.
If this exterior high humidity is a constant year around condition, you could alter the consequences to some degree by mounting a tight-sealing quality storm door, if you don't already have one, and then leave the prime door open as much as possible exposing that exterior side to the drier ACed air of the interior for as long as possible and to the high humidity for as little as possible. You could accelerate the benefits of this by circulating air over that side of the door with an appropriately positioned fan blowing at a low to moderate pace. Are you or your wife home alot? The combination of the storm door and the fan might allow you to get the door flat again while it's still mounted.
As for any notion of using batons/rails to restrain the door………….yes, it can be done, but it must be done right or it'll cause the door to split. You can't totally prevent this door from changing dimensionally, but you can "herd" that movement to some degree, effectively cohearsing most of "would-be" cup into lateral movement. If this happens, there must be somewhere for that wood to grow into. That may be part of your problem now......the swollen wood has crammed itself against the jamb, forcing itself into a bow...???
"Since your door is recessed and not exposed to rain or UV, multiple coats a high quality oil-based poly should serve you as an effective moisture barrier."
Test at the Foreset Product Lab show that a finish is not really a moiture barrier. It just a retarder. It will just slow done the problem not fix it.
Bill, bill, bill....
Recommend that you read the post again. I've clearly stated that no finish can totally prevent the absorption of moisture and have stated so many times before. "Effective moisture barrier" means just that.......an effective barrier.....not a moisture absorption preventer. The phrase "effective moisture barrier" is used by every author who ever wrote a book on the subject.
Are we in a contentious mood today? Knowledge is power, but only if applied in a timely fashion.
no finish can totally prevent the absorption of
moisture
Now then..........before someone corrects the above statement, let me reword............... No finish can totally prevent the exchange of moisture/water vapor.
Yes, it's a two-way street with moisture/water vapor.......the in of it and the out of it.
Knowledge is power, but only if applied in a timely fashion.
Thanks for the detailed reply. As to:
"Out of curiosity, how long did it take for the door to achieve it's current condition once it had been hung? " I noticed the door had a bow 3 to 4 weeks after the customer took possession in December. I knew immediately the heated interior was responsible for the door movement.
"Is the door made of quartersawn stock?" Good question, one I should have asked, and looked for. When the door arrived I checked the top and bottom to assess the joint quality in the door construction. The boards used were of slightly different widths, I presumed the shop cut out all defects and utilized the straightest and clearest boards to make the slab. The V-grooves were cut in after glue-up.
"That may be part of your problem now......the swollen wood has crammed itself against the jamb, forcing itself into a bow...??? " Fortunately, the door has bowed as a result of the moisture difference and not swollen to the point that opening the door is an issue. The door lock is having difficulty engaging the strike plate. I am contemplating, as a temporary solution, to move the strike plate out to allow the bolt to engage easier. Right now is not a good time to be removing the door, unless of course I construct another 8' high door slab with a 3' radius top. If this were a standard size front door, installing a temp door while addressing the bowed door would be very easy. However, I need to have the bowed door out of its frame for as short a time as possible. I know my customer does not want to look at a mishmash of materials to represent a temp door. Any ideas? Strategies?
I've never tried this but, it seems to me that a possible solution might be an adaptation of the "fixing warped doors" article on page 34 of the Nov. issue #150 of FHB. A twisted steel rod is inserted into the bottom of the door, could be done in about 1/2 hour with a drill and a routerI'm thinking a machine shop could conform the proper steel to your application as you are going to need some serious tension to straighten up an 8' door. As for why the door warped? You did everything right, proper storage, sealed endgrain, but a 1 3/8" exterior door, 8' tall, constructed in the fashion you described is just begging for trouble. The door should be minimum 2" and of panel construction but we all know that customers would like to save a dollar or two, and Designers are more concerned with "looks" than function and we always end up holding the bag.
sometimes board sometimes knot