How to fix a door that won't latch

Diagnose it in two minutes

Rub a little lipstick, chalk or a dry-erase marker on the end of the latch bolt, then close the door gently so the latch touches the strike plate. The mark shows exactly where the latch is hitting. Now you know whether it is high, low or just short of the hole.

Fix 1: tighten the hinges

1. Tighten every hinge screw, on the door and on the frame.
2. If a screw in the top hinge spins without biting, replace it with a 3-inch screw driven through the jamb into the wall framing. This pulls the top of the door back toward the frame and lifts the latch side.
3. Close the door and check the latch again.

This single fix solves many latching problems, because a sagging top hinge is the most common cause.

Fix 2: adjust the strike plate

If the latch is only slightly off, file the inside edge of the strike plate opening with a metal file until the latch drops in. For a bigger miss, unscrew the strike, extend the mortise in the jamb with a chisel in the direction you need, fill the old screw holes with glued wood slivers or toothpicks, and remount the plate. Adjustable strike plates are also available and make future adjustments easy.

Fix 3: shim a hinge

If the latch hits low, a thin cardboard shim behind the bottom hinge leaf on the frame side tilts the door up slightly. A shim behind the top hinge does the opposite. Shim one hinge at a time and test after each change.

Fix 4: free up the latch

If the latch bolt is slow to spring out, remove the knob or lever, clean the latch with a dry lubricant such as graphite or a silicone spray, and reinstall it. If it still sticks, a replacement latch costs little; take the old one to the store to match the backset (the distance from the door edge to the centre of the knob hole).

Exterior doors

On exterior doors, new weatherstripping that is too thick can push the door back so it will not latch without slamming. Moving the strike plate slightly toward the stop usually fixes it; see door weatherstripping. A split or soft frame around the strike is a different job: see door frame repair.

Wet winters and condo doors

On the coast, doors take on moisture from October to April and shrink back in summer. A door that misses its latch in January may be fine in July, so do the gentle fixes first: tighten the hinges and adjust the strike before taking wood off the door. If it does need planing, seal the bare edge straight away, or it will swell more next winter than it did this one.

In a condo, the door from your suite to the hallway is normally fire-rated and has to close and latch by itself. If it will not, tell your building or strata manager rather than adjusting it yourself; a suite door that does not latch is a fire-safety problem for the whole floor.

When to call someone

If the door has warped, the frame is out of square, or the problem keeps returning each season, the fix may involve planing the door, resetting the frame, or replacing the door. See door frame repair, interior door replacement cost and how to fix a squeaky door.