Why your door will not latch, and the three fixes

Find out which one you have

Close the door slowly until the latch bolt touches the strike plate, and stop there. Now look at where the bolt is pointing. That one look answers most of it.

• The bolt hits above or below the hole. The door has dropped or lifted. That is hinges.
• The bolt hits the plate flat, short of the hole. The door is not closing far enough. That is the stop, the weatherstrip, or paint build-up.
• The bolt lines up but the door springs back open. The latch is catching the edge of the plate. That is the strike plate, and it is the easiest of the three.
• It latches but the door rubs the frame on the way. The frame has moved. That one needs a bit more thought.

Fix one: the hinge screws

Open the door, take hold of the handle and lift. If it moves, even a little, the top hinge has lost its grip. This is by far the commonest cause, and the reason is simple geometry: the top hinge carries most of the weight of the door, and the screws that came with the hinge are usually about three quarters of an inch long. They reach the jamb and nothing behind it.

The fix is to get a screw into the framing behind the jamb instead. One three-inch screw through the top hinge, driven in until it is just snug and no further, pulls the door back up into square. Over-tighten it and you drag the jamb inwards, which trades one problem for another.

If the holes themselves have gone soft and the screw turns without biting, the hole needs filling before anything else will hold. Wooden toothpicks or a glued hardwood plug, trimmed flush, then redrill. Filler on its own will not take a load.

Fix two: the strike plate

Rub a little lipstick or a soft pencil on the latch bolt, close the door against the plate, and open it again. The mark on the plate shows you exactly where the bolt is landing and how far out you are.

If it is out by a sixteenth of an inch, a file on the edge of the strike hole is enough. If it is out by an eighth or more, the plate comes off and moves, and the screw holes get plugged first so the new position holds. Shifting a plate without plugging the old holes is why the same door comes loose again a year later.

Fix three: the jamb has moved

Houses settle, and houses in the South Bay have had plenty of reasons to. If the gap between door and frame is wide at the top and tight at the bottom, or the door rubs in one spot halfway down, the frame itself is no longer square.

Here the right answer is usually to adjust what is adjustable — shim behind a hinge, move the strike, ease a high spot — and leave the frame alone. Re-hanging a door into a moved frame is a much bigger job than it looks, and on a hollow-core interior door it is rarely worth the money.

What about planing the door?

Taking wood off is the last resort, not the first, and it is permanent. Before anyone reaches for a plane, the hinges should have been tightened and the strike checked. A door that was planed to fix a hinge problem ends up with a gap you can see daylight through once the hinge is finally put right.

What this costs if you would rather not

This is the best-value visit on my list, because nobody ever has one door. By the time I am in the house, the bathroom door that sticks, the bedroom one that will not latch and four kitchen cabinet doors hanging crooked all get sorted in the same hour or two. In the older streets of Willow Glen and Cambrian that is the normal outcome.