Easy Fixes for Door Lock Issues

Maintaining your door locks will help keep your home and possessions safe. Many issues are easy to fix with a little elbow grease and know-how.

Check your alignment

Mortise locks have a stout rectangular bolt that fits in a recess in the door frame. The edges of the recess are usually reinforced with a metal plate, called a strike plate. If the bolt won't go into the recess or if your key is hard to turn when locking and unlocking the door, the likelihood is that something is out of alignment.

• Examine the gap between the edge of the door and the frame — it should be consistent all the way along. If the gap gets wider towards the bottom, the door has probably slumped on its hinges, making the lock catch on the bottom of the recess.
• To remedy, unscrew the bottom hinge of the door from the frame and pack it with stiff paper (try a piece of playing card or greeting card) until the gap is even.
• Lift the door by its handle and see if the lock now engages. If it does, your hinges are worn and due for replacement.
• If you don't want to take on this job, you can enlarge the lock recess instead; use a metal file to file away at the lower lip of the hole in the strike plate until the bolt fits into the hole.

Tighten up the fit of your lock

If your door rattles when it is locked, the lock itself may be loose or the recess for your mortise lock may be oversize, allowing the door to move in the wind.

• Fit a piece of weatherstripping on the inner edge of the door frame so that it pushes the door back slightly and makes the lock contact the striker plate.
• Tighten the screws that secure the lock on the edge of the door. If they won't tighten, replace them with longer screws, or put matchsticks in the holes to give the existing screws more to bite on.

Light it up with luminous paint

Paint a ring around your door lock using some luminous paint — this can be bought from hardware shops and is often used commercially to identify doors and fire exits.

Secure your home quickly

Some sliding patio doors and sliding windows have complex locking mechanisms. If yours fails, there's an easy way to secure your home while you sort out the problem.

• Measure the distance between the inner edge of the sliding door and the frame, and cut a piece of wood or an old broom handle to this length. Fit the wood into the track in which the doors slide; it will prevent anyone from opening the door.
• Check there's no debris on the track that might be stopping the door from closing; squirt a little WD-40 along the track and wipe it clean with a cloth. Check that the door hasn't slipped off its rollers; if it has, you'll need to lift it back into position.
• Some doors and windows can be adjusted up or down on their rollers — look for a hole on the edge of the door near the bottom, which may be covered by a plastic cap. There'll be one on both edges. Turn the adjusters with a screwdriver — usually clockwise for up and counterclockwise for down — until the door lock aligns properly.