Can I fix a warped plywood door?
November 28, 2009 4:45 PM   Subscribe

How to straigten a warped plywood door?

Our contractor fabricated a wooden bypassing sliding door to replace a rotting garage door. It's marine-grade plywood with cedar lap-joint siding glued and screwed to the street-facing side. Looks great, but one side of one of the doors is warping badly, I'd say about two inches. This affects the functionality of the door, making it difficult to slide the door open and shut.

Is it possible to remove the warp in the door permanently? When I see how other barn-type doors are constructed I always see a combination of wood and bolted-through metal braces -- yeah, that's how it should have been engineered to start with, but of course I didn't know that when we started.

If I added braces now, could I slowly remove the warp by gradually tightening the bolt (or would the wood split)? Or, would I be better off removing the door, applying damp cloths to both sides of the bend, lay it on a flat surface, and place sandbags on the bowed side?
posted by Izzy to Home & Garden (7 answers total)
I've never heard of anyone "removing" warp from a board which isn't screwed pretty firmly in place already. Rather than getting rid of the warp, you simply put enough tension on the board to make it lie flat.

You really want to get rid of it, I think you have to replace the board in question. This is almost always cheaper and less of a pain. Since it's presumably a multi-section door--most garage doors are--see if you can salvage or replace the siding and stick it on a new back board.
posted by valkyryn at 4:58 PM on November 28, 2009

I'm interested in a couple of things:

You say the door is made of plywood with cedar siding over it. Is there any kind of frame or is it just these pieces of wood?

Second, how does this door slide? Does it go into a gap? ...across the face of the garage? ...behind the opening inside the garage?

There are a couple of things that can be done depending on these factors.
posted by Old Geezer at 5:25 PM on November 28, 2009

Which side is warping? Or I should say which way is it bowing? Warping can occur for several reasons, the most common being one side of the board (or door) is absorbing more moisture than the opposing side. How old are the doors?
posted by archaic at 5:37 PM on November 28, 2009

Is the ply splitting?
posted by Max Power at 5:47 PM on November 28, 2009

Not sure by looking at it...but you can unwarp it by screwing it to something flat. At least partly unwarp it. So this would be reinforcing it the way it should have been made in the first place.
posted by sully75 at 7:12 PM on November 28, 2009

Response by poster: Old Geezer: inside-facing is marine ply, outside facing is cedar lap. The door is hung on rollers at the top, and these slide on a track mounted on the top of the frame. Door slides (sort of) on the inside of the frame. There's no channel at the bottom (lame, I know, but I didn't know this when we started), and no rollers to help things along.

Arcahic: it's warping toward the outside (warm side)--moisture could be the culprit, but this is LA, so perhaps not that big of a factor? The doors are one year old.

Max Power: The ply is sound.

posted by Izzy at 11:59 AM on December 3, 2009

Best answer: It sounds to me like the cedar is absorbing moisture while the plywood is not.
Figuring out a way to flatten door and then seal the weather side would seem to
be the answer. Of course how you flatten it is the hard part, I have seen screen doors
un-warped with a threaded rod and turnbuckle combination. I am not sure if that would
work in this case. Sometimes clamping or screwing a strongback (thick piece of wood or
metal) to the back can straighten a door, but that would limit its utility as a sliding door.
Good luck.
posted by archaic at 4:03 AM on December 4, 2009

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