Exterior doors that do not shut tight pose a security problem as well as being aggravating. Over time screws work loose inside wood jambs due to the changes in air temperature. Wood contracts and expands under heat and cold, causing the wood around the screws to separate. Adjusting an exterior installed door so that it shuts tighter usually involves simple adjustments to the hinges or strike plate. Sometimes it is necessary to use longer screws to secure hinges to the frame.
Things You'll Need
Close the exterior door slowly while watching the bottom of the door. If you notice the lock side of the door is lower than the hinge side, make adjustment to the hinges.
Open the door halfway and ask a friend to grab the door handle and pull up on it slightly. Tighten the screws securing the upper hinge to the door frame opening with a Phillips screwdriver. If the screws will not tighten, remove them and use new screws that are the same diameter as the old ones and at least 1 inch longer. This extra length gives the screws new wood to bite into when tightening.
Tighten the remaining hinge screws into the door jamb as necessary. Open and shut the door and check the operation. This usually resolves most issues with an exterior door not shutting tightly enough.
Shut the door slowly and notice where the latch makes contact with the strike plate, if the door still does not shut tightly. The latch might be hitting the plate too high or too low or might not be fully engaging the hole in the strike plate.
Loosen, but do not remove, the screws securing the strike plate to the door jamb with a Phillips screwdriver. Move the strike plate as necessary to line up with the door latch. Move the strike plate so the inside curve of the plate rests flush against the door jamb. Retighten the securing screws.
If these small adjustments do not resolve the problem, you might have a door frame that is out of level due to the settling of the home. This type of repair should be done by a professional since the door must be removed and the door frame readjusted to the home.