If your door isn't closing properly, there is a little space on the top, and it moves when you pull upward on the doorknob, you've got a sag. The movement isn't actually in the door but in the jamb, which is the vertical board that holds the door hinges to the doorway. It can become loose and pull away from the stud behind it over the years as the weight of the door drags on it. The solution is often as easy as driving longer screws into the jamb hinges so the door isn't just anchored to the jamb, but also to the stud behind it.

1. Step 1

   Open the door and stand facing the jamb.

2. Step 2

   Use your screwgun to remove all but one of the screws that hold the top hinge to the jamb. Generally, there will be three screws, so you'll remove two them. Make sure the very top screw is one of the ones you take out.

3. Step 3

   Stick the point of your first three-inch wood screw into the top hole that's been left from the removal of the hinge screws. Position your screwgun on the head of the new screw. Before you drive it in, grip the door handle with your free hand and pull firmly upward to lift the sagging door as high as it will go. Drive in the screw while continuing to pull up on the door.

4. Step 4

   Repeat the process for each of the other screw holes, filling them with three-inch screws while pulling up on the door. Then take out the one screw that you didn't earlier remove, and replace it with a three-inch screw as well.

5. Step 5

   If your door has three hinges, repeat the process with the middle hinge. It isn't necessary to do the bottom hinge.