When a screen door becomes warped, it usually does so because of excessive force being exerted on it, such as slamming the door shut or even not properly propping it open. The good thing is that warped screen doors are easy enough to repair as long as you know what you are doing.
Step 1 - Figure Out Where the Warp Is
You want to figure out which part of the door is hitting the doorjamb first—top or bottom. This will show you where the door is warped.
Step 2 - Do the Quick Fix Method
Place a pencil between the doorjamb and the door in the location of where the door is striking the doorjamb first. Leave the pencil in place for 30 minutes. Take the pencil out to see if the door has started to straighten. If the door has begun to straighten, but is still slightly warped, you will want to repeat the pencil in the door method. Do this a few more times until the screen door is no longer warped.
Step 3 - Remove Door
If the warp is too bad, the pencil method will not work, so you will need to move onto a different method. You will need to remove the door from its hinges using the correct tool, such as Allen wrenches or screwdrivers. Lay the door flat on the ground when you are done.
Step 4 - Remove Hardware
You will want to remove the screws that hold the edging of the screen door in place as well as the edging itself so that you expose the wood lining inside the door. If there are any locks or handles going through the wood, remove them.
Step 5 - Remove the Wood
Use a flat-head screwdriver to pry the wood out of the screen door.
Step 6 - Measure Wood
Measure the old piece of wood that you took out of the screen door. Using those measurements, you will need to purchase a new piece of wood that is roughly the same size, you might need to cut it to make it fit.
Step 7 - Replace the Wood
Once you have cut the wood to the exact measurements of the old wood, you will want to place it back inside the screen door.
Step 8 - Add Finishing Touches
If you had holes in the wood for locks or a handle, you will need to duplicate those holes in the wood so that everything fits correctly. Replace the edging to your screen door.
Step 9 - Apply Clear Sealant
Apply a thin bead of clear sealant to the seams in the door so you can protect the wood from the weather.
Step 10 - Fix the Door
Once the door is put back together and the sealant has dried, affix the door to its hinges.