Fix a Door That Won't Stay Shut

If a door won't stay shut, fixing it is a trial-and-error process. Here's the process:

1. Check to see if the latch bolt is sticking. If it is, try lubricating it with silicone.
2. Use a level to find out if the door is hung level. If it's not a perfect fit, adjust the hinges.
3. If it is hung correctly, examine the wear marks on the strike plate on the door frame to determine if it's out of alignment. For slight misalignment, make the strike-plate hole bigger with a file. For a larger misalignment, move the strike plate or replace it with a larger one.
4. If everything lines up and there's still a gap between the door and the frame, move the strike plate closer to the latch by inserting a wooden shim behind the strike plate.