When a door latch won’t catch, It’s because the latch doesn’t align with the hole in the strike plate. Sometimes you can clearly see the misalignment. If not, do the “lipstick test” (Photo 1).Tighten the hinges first.
If you find that the latch contacts the strike plate too high or too low, make sure all the door’s hinge screws are tight. If that doesn’t solve the problem, try this trick: Remove one of the screws on the jamb side of the hinge and drive in a 3-in. screw. The long screw will grab the wall framing and draw in the whole doorjamb slightly. To raise the latch, do this at the top hinge. To lower the latch, do it at the bottom hinge.Enlarge the strike plate hole.
If long screws don’t solve the too-high or too-low problem, measure the misalignment of the lipstick marks on the strike plate. If the latch misses the strike plate hole by 1/8 in. or less, remove the strike plate and enlarge its hole with a file (Photo 2). A half-round file (sold at home centers and hardware stores) matches the curve of the latch hole.Move the strike plate.
If the latch contacts the strike plate at the correct level but doesn’t go in far enough, or if the latch strikes more than 1/8 in. too high or too low, you’ll have to reposition the strike plate. You can move it up or down and in or out. Use a sharp chisel to enlarge the strike plate mortise (Photo 3). Then hold the strike plate in place and drill new 1/16-in. holes for the screws. Install the strike plate and fill the gap in the mortise with wood filler. Remove the strike plate to paint or finish the patch.