How to Fix a Plywood Door From Warping

Remove the door from its hinges. Place a layer of plastic sheeting on a worktable table and then place the door on top of the plastic. The door should be placed so that the convex side -- the bowed out side -- is facing up.

Wet several large towels with hot water. Place them across the part of the door that is bowed. Cover the door with a sheet of plastic.

Place two small towels in the areas where the clamps will be applied to protect the surface. Clamp the door securely to the worktable. If the door is small, such as a kitchen cabinet, clamping at either end should be sufficient. If the door is large, you might want to clamp it on all sides.

Optionally, you can wrap the door in an electric blanket at this point to keep the towels warm enough for the moisture to penetrate the wood. Or, run a hot iron over the warped area with a towel in between the plywood and the iron. The idea is to force moisture and heat into the wood to soften it and help to bend back into shape.

Let the door sit on the worktable for a minimum of 24 hours. Check the area under the wet towels occasionally to see if the plywood door is flattening out. Re-wet the towels if necessary.

Check the door after 24 hours to see if the door has flattened out. If so, remove the wet towels and plastic and turn the door over. Place a heavy weight, such as brick or a couple of 2-by-4s on the area that was warped and then re-clamp the door. Allow the door to dry out for at least 24 hours.